1
|
Shu N, He Y, Zhang Y. Research progress on measurement methods and clinical applications of corneal elastic modulus. Exp Eye Res 2024; 245:109974. [PMID: 38897271 DOI: 10.1016/j.exer.2024.109974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 06/21/2024]
Abstract
Various corneal diseases are strongly associated with corneal biomechanical characteristics, and early measurement of patients' corneal biomechanics can be utilized in their diagnosis and treatment. Measurement methods for corneal biomechanical characteristics are classified into ex vivo and in vivo. Some of these methods can directly measure certain corneal biomechanical parameters, while others require indirect calculation through alternative methods. However, due to diversities in measurement techniques and environmental conditions, significant differences may exist in the corneal mechanical properties measured by these two methods. Therefore, comprehensive research on current measurement methods and the exploration of novel measurement techniques may have great clinical significance. The corneal elastic modulus, a critical indicator in corneal biomechanics, reflects the cornea's ability to return to its initial shape after undergoing stress. This review aims to provide a comprehensive summary of the corneal elastic modulus, which is a critical biomechanical parameter, and discuss its direct, indirect, and potential measurement methods and clinical applications.
Collapse
Affiliation(s)
- Nanqi Shu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, Jilin Province, China
| | - Yuxi He
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, Jilin Province, China
| | - Yan Zhang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, Jilin Province, China; Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China.
| |
Collapse
|
2
|
Cehelyk EK, Syed ZA. Long-term outcomes of corneal crosslinking. Curr Opin Ophthalmol 2024; 35:315-321. [PMID: 38700950 DOI: 10.1097/icu.0000000000001054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
PURPOSE OF REVIEW This manuscript summarizes contemporary research from 2018 to 2023 evaluating long-term (≥2 years) outcomes of corneal crosslinking (CXL) for progressive keratoconus (KCN). RECENT FINDINGS The standard Dresden protocol (SDP) has been utilized clinically since the early 2000 s to treat ectatic disorders, primarily progressive KCN and postrefractive ectasia. Various modifications have since been introduced including accelerated and transepithelial protocols, which are aimed at improving outcomes or reducing complications. This review summarizes data demonstrating that the SDP halts disease progression and improves various visual and topographic indices (UDVA, CDVA, Kmax, K1, K2) up to 13 years postoperatively. Accelerated and transepithelial protocols have been found to be well tolerated alternatives to SDP with similar efficacy profiles. Studies focusing on pediatric populations identified overall higher progression rates after CXL. All protocols reviewed had excellent safety outcomes in adults and children. SUMMARY Recent studies revealed that SDP successfully stabilizes KCN long term, and a variety of newer protocols are also effective. Pediatric patients may exhibit higher progression rates after CXL. Further research is required to enhance the efficacy and ease of these protocols.
Collapse
Affiliation(s)
| | - Zeba A Syed
- Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
| |
Collapse
|
3
|
Tholvsen M, Makdoumi K. The impact of interrupted corneal collagen crosslinking (CXL) treatment. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06505-x. [PMID: 38888803 DOI: 10.1007/s00417-024-06505-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 03/21/2024] [Accepted: 05/01/2024] [Indexed: 06/20/2024] Open
Abstract
PURPOSE To evaluate progression of keratoconus in patients where CXL treatment was interrupted due to insufficient swelling of the cornea. METHODS A retrospective review was conducted of all patients with keratoconus diagnosis who underwent CXL at the Department of Ophthalmology, Örebro University Hospital (USÖ) during the years 2010-2017. In total 377 eyes of 280 patients were screened for inclusion. In 17 eyes (15 patients), the treatment was interrupted due to insufficient swelling of the cornea. Patient journals were reviewed and keratometry examinations were analysed for long-term progression. RESULTS Eleven eyes (nine patients) were included in the study. Five eyes showed no signs of progression after the interrupted CXL treatment. In one eye progression continued, however, first after a period of a number of years, indicating a delayed course of clinical progression. CONCLUSION This study indicates that debridement of the corneal epithelium and riboflavin administration without intense UVA radiation may slow or arrest the progression of keratoconus, likely due to photosensitisation from ambient light.
Collapse
Affiliation(s)
- Marit Tholvsen
- Department of Ophthalmology, Falu Hospital, Falun, Sweden
- Center for Clinical Research, Dalarna, Uppsala University, Uppsala, Sweden
| | - Karim Makdoumi
- Department of Ophthalmology, Faculty of Medicine and Health, Orebro University, Orebro, Sweden.
| |
Collapse
|
4
|
Patel RP, Kabbani J, Angunawela R, Bizrah M. A Standardized Protocol of Simultaneous Transepithelial Phototherapeutic Keratectomy (PTK) Followed by Corneal Collagen Crosslinking for Keratoconus. Cornea 2024:00003226-990000000-00578. [PMID: 38900717 DOI: 10.1097/ico.0000000000003595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 05/05/2024] [Indexed: 06/22/2024]
Abstract
PURPOSE To report outcomes in patients with progressive keratoconus who underwent a standardized protocol of transepithelial phototherapeutic keratectomy (t-PTK) laser followed by accelerated corneal collagen crosslinking (CXL). METHODS All patients with progressive keratoconus undergoing our protocol at a London clinic between 2019 and 2023 were included. The protocol involved t-PTK at 58-μm central ablation depth at a 9-mm treatment zone on the Schwind Amaris 1050RS platform. Preoperative K readings of 43.0D (both K1 and K2) were inputted for all cases. Patients then underwent CXL with a pulsed-light accelerated protocol (30 mW/cm2 for 8 minutes of UVA exposure time with 1 second on/1 second off). RESULTS Seventy-nine eyes from 55 patients were included with an average follow-up of 12 months (range 6-24 months). Both mean uncorrected distance visual acuity (UDVA) and best spectacle-corrected visual acuity improved significantly from 0.42 preoperatively to 0.29 postoperatively (P < 0.01) and 0.11 to 0.06 postoperatively (P < 0.01), respectively. The refractive cylinder reduced significantly from -3.07D to -2.63D (P < 0.05). The mean Km improved from 46.15D to 45.44D (P < 0.01) and mean Kmax from 54.03D to 52.52D (P < 0.01). 77% of eyes (n = 61) exhibited Kmax improvement postoperatively, and 56% showed an improvement in UDVA (n = 44). 16% (n = 13) had worsening of vision, but of these, only 1 patient had visual loss of more than 2 lines. No eyes had corneal haze reported at the final follow-up, and none required additional treatment. CONCLUSIONS This standardized simultaneous t-PTK and CXL protocol is safe and effective for the treatment of progressive keratoconus, providing visual, refractive, and topographic improvements.
Collapse
Affiliation(s)
- Radhika Pooja Patel
- Imperial College Healthcare NHS Trust, Western Eye Hospital, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Jamil Kabbani
- Royal Surrey County Hospital, Guildford, United Kingdom
| | - Romesh Angunawela
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- OCL Vision, London, United Kingdom; and
| | - Mukhtar Bizrah
- Imperial College Healthcare NHS Trust, Western Eye Hospital, London, United Kingdom
- Harley Vision, St John & St Elizabeth Hospital, London, United Kingdom
| |
Collapse
|
5
|
Hira S, Klein Heffel K, Mehmood F, Sehgal K, Felix De Farias Santos AC, Steuernagel Del Valle G. Comparison of refractive surgeries (SMILE, LASIK, and PRK) with and without corneal crosslinking: systematic review and meta-analysis. J Cataract Refract Surg 2024; 50:523-533. [PMID: 38288954 DOI: 10.1097/j.jcrs.0000000000001405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/22/2024] [Indexed: 04/24/2024]
Abstract
Corneal crosslinking (CXL) is used for treating keratoconus and post-laser in situ keratomileusis ectasia. However, refractive surgery is not usually performed with prophylactic CXL. Therefore, we performed a meta-analysis comparing outcomes of refractive surgeries with vs without prophylactic CXL. We systematically searched databases for studies comparing refractive surgeries for myopic correction with vs without prophylactic corneal crosslinking. Review Manager 5.4.1 was used to perform statistical analysis. We included 2820 eyes from 28 studies. Compared with refractive surgery alone, surgery with prophylactic CXL resulted in decreased central corneal thickness, corrected distance visual acuity logMAR, and safety and efficacy indices. There were no significant differences in postoperative uncorrected distance visual acuity of 20/20 or better at ≥12 months and other visual outcomes among both groups. More randomized controlled trials with standard crosslinking protocols are needed to analyze the prophylactic use of crosslinking with refractive surgeries.
Collapse
Affiliation(s)
- Sara Hira
- From the FMH College of Medicine & Dentistry, Lahore, Pakistan (Hira); Federal University of Pelotas, Pelotas, Brazil (Klein Heffel); Department of Ophthalmology, Fatima Memorial Hospital, Lahore, Pakistan (Mehmood); Teerthanker Mahaveer University, Moradabad, UP, India (Sehgal); City University of São Paulo, São Paulo, Brazil (Felix De Farias Santos); University of Iowa, Iowa City, Iowa (Steuernagel Del Valle)
| | | | | | | | | | | |
Collapse
|
6
|
Salvador-Culla B, Afsara A, Roper N, Mulroy J, Galankova L, Duncan H, Tabibian D, Lamarca-Mateu J, Figueiredo FC. Accelerated Corneal Crosslinking to Arrest Progression of Corneal Ectasia: A Prospective Multicenter Study. Eye Contact Lens 2024; 50:126-131. [PMID: 38345049 DOI: 10.1097/icl.0000000000001065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2023] [Indexed: 02/21/2024]
Abstract
OBJECTIVES To report the results of epithelium-off accelerated corneal collagen crosslinking (accelerated corneal crosslinking [ACXL]) in patients with progressive keratoconus. METHODS This prospective, nonrandomized, noncomparative, interventional, multicenter clinical study included all patients who underwent ACXL, either continuous (c-ACXL; 9 mW/cm 2 , 10', 5.4 J/cm 2 ) or pulsed (p-ACXL; 2″ON/1″OFF, 30 mW/cm 2 , 4.5', 5.4 J/cm 2 ) between January 2014 and May 2017. Best-corrected visual acuity, sphere, cylinder, spherical equivalent, and topographical keratometry data were collected preoperatively and at 1, 3, 6, 12, 18, and 24 months postoperatively. RESULTS Ninety-six eyes of 78 patients were included. The mean age was 20.8±4.4 years (14-33) for c-ACXL and 26.7±7.7 years (12-37) for p-ACXL. The mean best-corrected visual acuity was 0.4±0.4 for c-ACXL and 0.01±0.1 for p-ACXL preoperatively, and 0.3±0.3 ( P =0.0014) and -0.01±0.1 ( P =0.1554), respectively, at the last follow-up. The subjective sphere and spherical equivalent did not show statistically significant differences between the time points ( P >0.05). The subjective cylinder showed significant differences ( P =0.0013 for c-ACXL; P =0.0358 for p-ACXL). Keratometric values (K steep , K flat , and SimK) remained stable, with no statistically significant differences ( P >0.05). No major complications were noted. CONCLUSIONS Both c-ACXL and p-ACXL are equally safe and effective ACXL protocols in stabilizing the progression of keratoconus and can be considered alternatives to the conventional Dresden protocol.
Collapse
Affiliation(s)
- Borja Salvador-Culla
- Department of Ophthalmology (B.S.-C., A.A., N.R., J.M., L.G., H.D., D.T., F.C.F.), Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom; Centro de Oftalmología Barraquer (B.S.-C., J.L.-M.), Instituto Universitario Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain; Department of Ophthalmology (D.T.), University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland; and Biosciences Institute (F.C.F.), Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Cronin B, Gunn D, Chang CY. Oxygen-supplemented and topography-guided epithelium-on corneal crosslinking with pulsed irradiation for progressive keratoconus. J Cataract Refract Surg 2024; 50:209-216. [PMID: 38381615 PMCID: PMC10878465 DOI: 10.1097/j.jcrs.0000000000001339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 02/23/2024]
Abstract
PURPOSE To investigate the effects of customized topography-guided epithelium-on crosslinking (epi-on CXL) with oxygen supplementation on procedural efficacy and corrected distance visual acuity (CDVA) in patients with progressive keratoconus (KC) at 1 year. SETTING Private eye clinic, Brisbane, Australia. DESIGN Retrospective, single-center, nonrandomized case series. METHODS Topography-guided epi-on CXL using the Mosaic system was performed on patients with progressive KC. Oxygen goggles; transepithelial riboflavin; and pulsed, high UV-A irradiance (1 second on, 1 second off; 30 mW/cm2) were applied to enhance oxygen kinetics and bioavailabilities of riboflavin and UV-A. Guided by baseline topography, a higher UV-A dose (15 J/cm2) was applied to the area of steepest anterior curvature with decreasing fluence (as low as 7.2 J/cm2) toward the outer 9 mm. Postoperative CDVA and maximum keratometry (Kmax) were evaluated. RESULTS 102 eyes (80 patients) were followed for 11.5 ± 4.8 months. At the latest follow-up, mean CDVA (logMAR), mean K, and Kmax (diopters [D]) improved from 0.18 ± 0.28, 46.2 ± 3.8, and 53.0 ± 5.67 at baseline to 0.07 ± 0.18, 45.8 ± 3.7, and 51.9 ± 5.56, respectively (P < .001). 3 eyes (3%) lost more than 1 CDVA line, and another 3 eyes (3%) had increased Kmax greater than 2 D. 43 eyes were followed for at least 12 months (n = 43): mean CDVA, mean K, and Kmax improved from 0.19 ± 0.33 logMAR, 46.5 ± 3.5 D, and 53.6 ± 5.67 D to 0.07 ± 0.17 logMAR, 46.0 ± 3.5 D, and 52.33 ± 5.49 D, respectively (P ≤ .002). No complications were observed. CONCLUSIONS Tailoring oxygen-supplemented epi-on CXL with differential UV-A energy distributions, guided by baseline topography, in patients with KC seems to be safe and effective. At 1 year, study reports sustained improved CDVA and corneal stabilization.
Collapse
Affiliation(s)
- Brendan Cronin
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Gunn); Medical Affairs, Burlington, Massachusetts (Chang); Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania (Chang)
| | - David Gunn
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Gunn); Medical Affairs, Burlington, Massachusetts (Chang); Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania (Chang)
| | - Clark Y. Chang
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Gunn); Medical Affairs, Burlington, Massachusetts (Chang); Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania (Chang)
| |
Collapse
|
8
|
Gupta AS, Yu Y, Orlin SE, VanderBeek BL. Real-world socioeconomic determinants of corneal crosslinking in a national cohort. J Cataract Refract Surg 2024; 50:217-223. [PMID: 37847112 PMCID: PMC10878448 DOI: 10.1097/j.jcrs.0000000000001340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/24/2023] [Accepted: 10/08/2023] [Indexed: 10/18/2023]
Abstract
PURPOSE To characterize recent socioeconomic trends in patients with keratoconus/corneal ectasias undergoing corneal crosslinking (CXL). SETTING A deidentified administrative medical claims database comprised commercial and Medicare Advantage health claims from across the United States. DESIGN Population-based retrospective cohort study. METHODS This study identified 552 patients with keratoconus/corneal ectasia who underwent CXL and 2723 matched controls who did not undergo CXL based on Current Procedural Terminology coding from a U.S. national insurance claims database from 2016 to 2020. For each patient, characteristics, including sex, race, age, household net worth, education level, insurance plan type, and geographic region, were extracted. Multivariate logistic regression was conducted to determine the odds of undergoing crosslinking. RESULTS Age 30 years or older (odds ratio [OR], 0.34, P < .001) was associated with decreased likelihood of undergoing CXL. Sex, race, education, and patient income were not associated with odds of undergoing CXL. Patients with health maintenance organization insurance had lower odds of undergoing CXL (OR, 0.64, P = .047). Geographically, patients on the east coast (OR, 0.37, P < .001) and Lower Midwest (OR, 0.31, P < .001) had statistically lower odds of undergoing crosslinking. CONCLUSIONS This is the first study to identify socioeconomic determinants of CXL, and it highlights that geographic location and insurance type may limit accessibility to patients.
Collapse
Affiliation(s)
- Angela S. Gupta
- From the Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania (Gupta, Orlin, VanderBeek); Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (Yu); Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek); Leonard Davis Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek)
| | - Yinxi Yu
- From the Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania (Gupta, Orlin, VanderBeek); Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (Yu); Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek); Leonard Davis Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek)
| | - Stephen E. Orlin
- From the Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania (Gupta, Orlin, VanderBeek); Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (Yu); Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek); Leonard Davis Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek)
| | - Brian L. VanderBeek
- From the Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania (Gupta, Orlin, VanderBeek); Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (Yu); Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek); Leonard Davis Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania (VanderBeek)
| |
Collapse
|
9
|
Friedrich J, Sandner A, Nasseri A, Maier M, Zapp D. Accelerated corneal cross-linking (18mW/cm2 for 5 min) with HPMC-riboflavin in progressive keratoconus - 5 years follow-up. Graefes Arch Clin Exp Ophthalmol 2024; 262:871-877. [PMID: 37672103 PMCID: PMC10907430 DOI: 10.1007/s00417-023-06225-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 08/15/2023] [Accepted: 08/26/2023] [Indexed: 09/07/2023] Open
Abstract
PURPOSE To evaluate long-term results of accelerated corneal cross-linking (ACXL) in patients with progressive keratoconus, seventy-four eyes of 53 patients with progressive keratoconus (documented Kmax progression > 1D/a) who underwent ACXL (18mW/cm2 for 5 min) were included in a retrospective observational clinical study. The investigation focused on tomographic and keratometric parameters, refractive data, and visual outcomes at 5 years follow-ups. METHODS Corrected distance visual acuity (CDVA), slit lamp, and Pentacam® examinations were conducted, including assessments of thinnest corneal point (TP), minimum radius (Rmin), corneal astigmatism, and maximum anterior keratometry (Kmax). These examinations were performed two weeks before the surgery and, on average, 56 months after the surgery. In a subgroup of 24 eyes, Pentacam® examination data from an intermediate visit at 12 months until the final visit was evaluated to confirm continuous stability. The ACXL protocol included corneal abrasion, hydroxypropylmethylcellulose (HPMC)-riboflavin eye drops administered every 5 min for a total duration of 30 min, and irradiation with 18mW/cm2 for 5 min using riboflavin eye drops applied every minute during the irradiation process. Intraoperatively, minimal corneal pachymetry of > 400 µm was ensured in every patient. RESULTS After 56 months, all values exhibited statistically significant changes (paired t-test; CDVA p = 0.002; Kmax p < 0.001; Rmin p < 0.001; astigmatism p = 0.03; TP p < 0.001). In the subgroup analysis of 24 eyes, which included tomographical and keratometric parameters, no statistically significant changes were observed during the last 12 months of observation (paired t-test; Kmax p = 0.72; Rmin p = 0.67; astigmatism p = 0.72). Treatment failure was strictly defined as an increase in Kmax (> 1D) during the 5-year follow-up and was observed in only 3 eyes (4%). CONCLUSIONS ACXL is an effective and safe treatment for patients with progressive keratoconus. Our results demonstrate improvements in functional and tomographical outcomes even after high-energy ACXL (18mW/cm2 for 5 min) over a long-term period of 56 months. Our analysis indicates stable conditions in previously progressive keratoconus, particularly during the final year of the observation period. The treatment failure rate was 4%.
Collapse
Affiliation(s)
- Julia Friedrich
- Klinik und Poliklinik für Augenheilkunde, Klinikum rechts der Isar, TUM, Munich, Germany.
| | - Alexandra Sandner
- Klinik und Poliklinik für Augenheilkunde, Klinikum rechts der Isar, TUM, Munich, Germany
| | - Ali Nasseri
- Technische Universität München, Munich, Germany
| | - Mathias Maier
- Klinik und Poliklinik für Augenheilkunde, Klinikum rechts der Isar, TUM, Munich, Germany
| | - Daniel Zapp
- Klinik und Poliklinik für Augenheilkunde, Klinikum rechts der Isar, TUM, Munich, Germany
| |
Collapse
|
10
|
Hacıağaoğlu S, Akkaya Turhan S, Toker E. A comparison of conventional and accelerated corneal crosslinking: corneal epithelial remodeling and in vivo confocal microscopy analysis. Int Ophthalmol 2024; 44:87. [PMID: 38363414 DOI: 10.1007/s10792-024-03020-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 01/09/2024] [Indexed: 02/17/2024]
Abstract
PURPOSE To evaluate the effect of conventional and accelerated corneal crosslinking (CXL) on visual acuity, corneal topography, corneal epithelial thickness, and subbasal nerve morphology in progressive keratoconus patients. METHODS In this prospective and randomized study, twenty eyes of 20 patients were treated with conventional CXL (3 mW/cm2, 30 min, C-CXL) and 19 eyes of 19 patients were treated with accelerated CXL (9 mW/cm2, 10 min, A-CXL). The spherical equivalent, uncorrected visual acuity, best-corrected visual acuity, keratometric measurements, demarcation line measurement and epithelial thickness mapping analyses, and subbasal nerve morphology with in vivo confocal microscopy (IVCCM) were evaluated at baseline and at postoperative months 1, 3 and 6. RESULTS At postoperative 6 months, a significant improvement was observed in all keratometric values in both treatment groups (p < 0.05). All epithelial thickness indices, except central, temporal, and inferotemporal thickness, were reduced at 1 month postoperatively in both treatment groups. The epithelial map uniformity indices (standard deviation and difference between min-max thickness) were significantly lower than the baseline values at all time points after CXL in both treatment groups (p < 0.001). Compared with the preoperative values, there was a significant decrease in all IVCCM parameters at 1 month postoperatively (p < 0.05). At 6 months postoperatively, corneal nerve fiber density and corneal nerve branch density recovered to preoperative values in the A-CXL group, whereas corneal nerve regeneration was not complete in the C-CXL group. CONCLUSION Both conventional and accelerated CXL treatments appear to be effective in halting the progression of KC. Corneal epithelial irregularity slightly improves after CXL. The regeneration of subbasal nerves is faster after A-CXL treatment.
Collapse
Affiliation(s)
- Sezer Hacıağaoğlu
- Department of Ophthalmology, Bahçeşehir University, Sahrayıcedit Mah. Batman Sk. No:66, 34734 Kadıköy, Istanbul, Turkey.
| | - Semra Akkaya Turhan
- Department of Ophthalmology, Marmara University, Marmara Üniversitesi Pendik Eğitim ve Araştırma Hastanesi, Fevzi Çakmak Mah. Muhsin Yazıcıoğlu Cad. No:10 Pendik, Istanbul, Turkey
| | - Ebru Toker
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, United States
| |
Collapse
|
11
|
Vilares-Morgado R, Ferreira AM, Cunha AM, Moreira R, Torrão L, Neves-Cardoso P, Pinheiro-Costa J. Transepithelial Accelerated Crosslinking for Progressive Keratoconus: A Critical Analysis of Medium-Term Treatment Outcomes. Clin Ophthalmol 2024; 18:393-407. [PMID: 38348140 PMCID: PMC10860395 DOI: 10.2147/opth.s450916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 01/24/2024] [Indexed: 02/15/2024] Open
Abstract
Purpose To report the 4-year outcomes of transepithelial accelerated corneal collagen crosslinking (TE-ACXL) in the treatment of eyes with progressive keratoconus (KC). Methods Eyes of patients who underwent TE-ACXL (6mW/cm2 for 15 minutes) for progressive KC and presented 48 months of follow-up were included. Corrected distance visual acuity (CDVA), keratometry measurements (Kmax, maximum keratometry, Kmean, mean keratometry and Astg, corneal astigmatism), thinnest corneal thickness (PachyMin), and topographic, and tomographic indices (specifically the posterior radius of curvature from the 3.0 mm centered on the thinnest point of the cornea (PRC), and the D-index) were analysed preoperatively and every 12 months after TE-ACXL, up to 48 months. Progression after TE-ACXL was considered when eyes presented ≥1 criteria: (1) increase of ≥1D in Kmax or increase of ≥0.75D in Kmean or increase of ≥1D in Astg; (2) reduction of ≥0.085 mm in PRC; (3) decrease ≥5% in PachyMin. Results 41 eyes from 30 patients were included, with a mean age at crosslinking of 20.90±4.69 years. There was a significant increase in Kmean (+0.64±1.04 D, p<0.001; +0.98 ± 1.49 D, p<0.001; +1.27±2.01 D, p<0.001; +1.13±2.00 D, p=0.006) and a significant decrease in PRC throughout follow-up (-0.12±0.22, p=0.002; -0.15±0.24, p<0.001; -0.17±0.43, p=0.021; -0.16±0.43, p=0.027). PachyMin decreased significantly at 36 and 48 months (-8.50±15.93 μm, p=0.004; -7.82±18.37, p=0.033). According to our progression criteria, there was a major progression rate throughout follow-up (57.1%, 61.1%, 58.8%, and 67.9%, respectively). Surgery and follow-up were uneventful in all subjects. Eleven eyes (26.8%) required further procedures, ≥36 months after the initial TE-ACXL, due to persistent progressive disease. Conclusion TE-ACXL proved to be a safe therapeutic option for progressive KC. However, its efficacy is deemed unsatisfactory, as a notable proportion of affected eyes may continue to advance within a 4-year timeframe, necessitating additional procedures to halt the disease's course.
Collapse
Affiliation(s)
- Rodrigo Vilares-Morgado
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
| | - Ana Margarida Ferreira
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
| | - Ana Maria Cunha
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
| | - Raúl Moreira
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
| | - Luís Torrão
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
| | - Pedro Neves-Cardoso
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
| | - João Pinheiro-Costa
- Department of Ophthalmology, Centro Hospitalar Universitário de São João, Porto, Portugal
- Department of Surgery and Physiology, Faculty of Medicine of Porto University, Porto, Portugal
- Department of Biomedicine, Faculty of Medicine of Porto University, Porto, Portugal
| |
Collapse
|
12
|
Naranjo A, Manche EE. A comprehensive review on corneal crosslinking. Taiwan J Ophthalmol 2024; 14:44-49. [PMID: 38654993 PMCID: PMC11034691 DOI: 10.4103/tjo.tjo-d-23-00055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 09/01/2023] [Indexed: 04/26/2024] Open
Abstract
Corneal crosslinking (CXL) represents a paradigm shift in the management of corneal ectatic disorders. Before CXL was introduced, patients would need specialty contact lenses and possible corneal transplantation. CXL involves a biochemical reaction in which ultraviolet A light is used in conjunction with Riboflavin to form crosslinks in between corneal stromal collagen. This leads to strengthening and stabilizing of the collagen lamellae, resulting in mechanical stiffening of the cornea. Multiple protocols have been proposed including epithelium on versus off and varying light intensity and duration of treatment. All protocols appear to be safe and effective with few reported complications including infection, stromal haze, scarring, and endothelial toxicity. Overall, CXL has demonstrated to halt the progression of the disease clinically and in keratometry readings and improve the quality of life for patients. It is a minimally invasive, cost-effective procedure that can be performed in an outpatient setting with a fast recovery time and long-lasting results.
Collapse
Affiliation(s)
- Andrea Naranjo
- Department of Ophthalmology, The Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California, USA
| | - Edward E. Manche
- Department of Ophthalmology, The Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California, USA
| |
Collapse
|
13
|
Deshmukh R, Shrivastava AK, Vaddavalli PK. Prevailing practice patterns in keratoconus among Indian ophthalmologists. Indian J Ophthalmol 2023; 71:3229-3234. [PMID: 37602613 PMCID: PMC10565949 DOI: 10.4103/ijo.ijo_595_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/19/2023] [Accepted: 06/30/2023] [Indexed: 08/22/2023] Open
Abstract
Objective The past few years have seen a rapid advancement in the management of keratoconus (KC). However, there is no prescribed standard of care for the management of KC. This study evaluated the prevailing practice patterns among Indian ophthalmologists in the diagnosis and treatment of KC via an online survey. Methods This was a survey-based cross-sectional study in which a questionnaire (Supplement 1) was created. Questions pertaining to the practicing experience, setting of practice, and training background were asked in addition to the investigations done and decision making in KC management. Responses were collected via Survey Monkey (Survey Monkey, Palo Alto, California, USA) and statistical analysis performed using R software (4.1.3). Results The survey was answered by 273 ophthalmologists. Pentacam was the most used topographer (195 users), followed by Orbscan (41 users), Sirius (34 users), and Galilei (3 users). The lowest limit of pachymetry for performing collagen crosslinking (CXL) was 400μ for most practitioners. More than half the respondents (50.55%) did not perform photorefractive keratectomy (PRK) or intracorneal ring segment (ICRS) implantation in a suitable patient. Accelerated 10-minute protocol (9 mW/cm2 for 10 minutes) was the most commonly (54.21%) used for CXL, followed by Dresden protocol (3 mW/cm2 for 30 minutes) (36.63%). When a patient was unsuitable for CXL, 55.31% surgeons advise contact lens (CL) trial, 35.16% surgeons advise keratoplasty, 26.74% surgeons perform stromal augmentation, and 7.69% surgeons advise spectacle correction. Corneal scar was the most common indication (49.45%) for performing keratoplasty. Conclusion Topography remains the most used diagnostic modality for initial diagnosis. Optical coherence tomography and epithelial mapping are increasingly being used for early diagnosis of KC. Not all ophthalmologists were comfortable performing ICRS or PRK. When patients are unsuitable for CXL, CL trial remains the most frequently advised option followed by keratoplasty.
Collapse
Affiliation(s)
- Rashmi Deshmukh
- Cataract and Refractive Services, LV Prasad Eye Institute, Hyderabad, Telangana, India
| | - Alok Kumar Shrivastava
- Cataract and Refractive Services, LV Prasad Eye Institute, Hyderabad, Telangana, India
- Sri Innovation and Research Foundation, Ghaziabad, Uttar Pradesh, India
| | - Pravin Krishna Vaddavalli
- Cataract and Refractive Services, LV Prasad Eye Institute, Hyderabad, Telangana, India
- Shantilal Sanghvi Eye Institute, Hyderabad, Telangana, India
| |
Collapse
|
14
|
Deshmukh R, Ong ZZ, Rampat R, Alió del Barrio JL, Barua A, Ang M, Mehta JS, Said DG, Dua HS, Ambrósio R, Ting DSJ. Management of keratoconus: an updated review. Front Med (Lausanne) 2023; 10:1212314. [PMID: 37409272 PMCID: PMC10318194 DOI: 10.3389/fmed.2023.1212314] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 05/30/2023] [Indexed: 07/07/2023] Open
Abstract
Keratoconus is the most common corneal ectatic disorder. It is characterized by progressive corneal thinning with resultant irregular astigmatism and myopia. Its prevalence has been estimated at 1:375 to 1:2,000 people globally, with a considerably higher rate in the younger populations. Over the past two decades, there was a paradigm shift in the management of keratoconus. The treatment has expanded significantly from conservative management (e.g., spectacles and contact lenses wear) and penetrating keratoplasty to many other therapeutic and refractive modalities, including corneal cross-linking (with various protocols/techniques), combined CXL-keratorefractive surgeries, intracorneal ring segments, anterior lamellar keratoplasty, and more recently, Bowman's layer transplantation, stromal keratophakia, and stromal regeneration. Several recent large genome-wide association studies (GWAS) have identified important genetic mutations relevant to keratoconus, facilitating the development of potential gene therapy targeting keratoconus and halting the disease progression. In addition, attempts have been made to leverage the power of artificial intelligence-assisted algorithms in enabling earlier detection and progression prediction in keratoconus. In this review, we provide a comprehensive overview of the current and emerging treatment of keratoconus and propose a treatment algorithm for systematically guiding the management of this common clinical entity.
Collapse
Affiliation(s)
- Rashmi Deshmukh
- Department of Cornea and Refractive Surgery, LV Prasad Eye Institute, Hyderabad, India
| | - Zun Zheng Ong
- Department of Ophthalmology, Queen’s Medical Centre, Nottingham, United Kingdom
| | - Radhika Rampat
- Department of Ophthalmology, Royal Free London NHS Foundation Trust, London, United Kingdom
| | - Jorge L. Alió del Barrio
- Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
- Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain
| | - Ankur Barua
- Birmingham and Midland Eye Centre, Birmingham, United Kingdom
| | - Marcus Ang
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore, Singapore
| | - Jodhbir S. Mehta
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore, Singapore
| | - Dalia G. Said
- Department of Ophthalmology, Queen’s Medical Centre, Nottingham, United Kingdom
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Harminder S. Dua
- Department of Ophthalmology, Queen’s Medical Centre, Nottingham, United Kingdom
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Renato Ambrósio
- Department of Cornea and Refractive Surgery, Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- Department of Ophthalmology, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Darren Shu Jeng Ting
- Birmingham and Midland Eye Centre, Birmingham, United Kingdom
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
15
|
Ross AKM, Schlunck G, Böhringer D, Maier P, Eberwein P, Reinhard T, Lang SJ. Characterization of the Immediate and Delayed Biomechanical Response to UV-A Crosslinking of Human Corneas. Cornea 2023; Publish Ahead of Print:00003226-990000000-00318. [PMID: 37335854 DOI: 10.1097/ico.0000000000003336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/26/2023] [Indexed: 06/21/2023]
Abstract
PURPOSE Keratoconus leads to visual deterioration due to irregular astigmatism and corneal thinning. Riboflavin-based corneal UV-A crosslinking (CXL) induces novel intramolecular and intermolecular links resulting in corneal tissue stiffening, thereby halting disease progression. The purpose of this study was to analyze the immediate and delayed biomechanical responses of human donor corneas to CXL. METHODS CXL was performed according to the Dresden protocol to corneas not suitable for transplantation. Biomechanical properties were subsequently monitored by measuring the Young modulus using nanoindentation. The immediate tissue response was determined after 0, 1, 15, and 30 minutes of irradiation. Delayed biomechanical effects were investigated with follow-up measurements immediately and 1, 3, and 7 days after CXL. RESULTS Young's modulus indicated a linear trend in direct response to increasing irradiation times (mean values: total 61.31 kPa [SD 25.53], 0 minutes 48.82 kPa [SD 19.73], 1 minute 53.44 kPa [SD 25.95], 15 minutes 63.56 kPa [SD 20.99], and 30 minutes 76.76 kPa [SD 24.92]). The linear mixed model for the elastic response of corneal tissue was 49.82 kPa + (0.91 kPa/min × time [minutes]); P < 0.001. The follow-up measurements showed no significant delayed changes in the Young modulus (mean values: total 55,28 kPa [SD 15.95], immediately after CXL 56,83 kPa [SD 18.74], day 1 50.28 kPa [SD 14.15], day 3 57.08 kPa [SD 14.98], and day 7 56.83 kPa [SD 15.07]). CONCLUSIONS This study suggests a linear increase of corneal Young modulus as a function of CXL timing. No significant short-term delayed biomechanical changes posttreatment were observed.
Collapse
Affiliation(s)
- Andrea K M Ross
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Günther Schlunck
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Daniel Böhringer
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Philip Maier
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | | | - Thomas Reinhard
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Stefan Johann Lang
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| |
Collapse
|
16
|
Wagner FM, Sekundo W. Iatrogenic Keratectasia after Refractive Surgery - Causes, Prophylaxis, Therapy. Klin Monbl Augenheilkd 2023; 240:783-794. [PMID: 37348513 DOI: 10.1055/a-2073-8478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Iatrogenic keratectasia is induced thinning and protrusion of the cornea after laser refractive surgery. Known risk factors include an excessively thin postoperative residual stromal bed, a thicker flap, or preoperatively undetected evidence of preexisting subclinical keratoconus. The rate of post-refractive ectasia in eyes without identifiable preoperative risk factors is 20 per 100 000 eyes for photorefractive keratectomy, 90 per 100 000 eyes for laser in situ keratomileusis, and 11 per 100 000 eyes for small incision lenticule extraction. Traditional screening tools for preoperative risk include the ectasia risk score system and percentage of tissue alteration. More recent methods include corneal elastography and epithelial mapping, in addition to Artificial Intelligence methods for data analysis. Therapy includes contact lenses, cross-linking, implantation of intracorneal ring segments, penetrating or lamellar keratoplasty, and, in early studies, implantation of corneal lenticules.
Collapse
Affiliation(s)
- Felix Mathias Wagner
- Universitätsaugenklinik Mainz, Mainz, Deutschland
- Universitätsaugenklinik Marburg, Marburg, Deutschland
| | | |
Collapse
|
17
|
Prasher P, Sharma A, Sharma R, Vig VK, Nirankari VS. Paediatric cornea crosslinking current strategies: A review. ADVANCES IN OPHTHALMOLOGY PRACTICE AND RESEARCH 2023; 3:55-62. [PMID: 37846374 PMCID: PMC10577868 DOI: 10.1016/j.aopr.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/13/2022] [Accepted: 11/16/2022] [Indexed: 10/18/2023]
Abstract
Background In the general population, 1 in 2000 people has keratoconus. Indians and other people from Southeast Asia have a higher incidence of keratoconus. Children with keratoconus typically present earlier in life and with a more severe disease. Rubbing the eyes has been identified as a risk factor. Children have a higher incidence and a faster rate of keratoconus progression. Visual rehabilitation in children with keratoconus is challenging. They have a low compliance with contact lens use. Many of these children require penetrating keratoplasty at an early age. Therefore, stopping the progression of keratoconus in children is of paramount importance. Main text Compared to treatment, keratoconus progression prophylaxis is not only preferable, but also easier. Corneal collagen cross-linking has been shown to be safe and effective in stopping its progression in children. The Dresden protocol, which involves central corneal deepithelization (7-9 mm), saturation of the stroma with riboflavin (0.25%), and 30 min UV-A exposure, has proven to be the most successful. Two significant disadvantages of the typical Dresden regimen are the prolonged operating time and the significant post-operative pain. Accelerated-CXL (9 mW/cm2 x 10 min) has been studied to reduce operative time and has been shown to be equally effective in some studies. Compared to accelerated CXL or traditional CXL, epi-off procedures, transepithelial treatment without the need for de-epithelialization and without postoperative discomfort, have been shown to be safer but less effective. Corneal crosslinking should only be performed after treating children with active vernal keratoconjunctivitis. Corneal opacity, chronic corneal edema, sterile infiltrates, and microbial keratitis have been reported after cross-linking of corneal collagen. Conclusions The "Dresden protocol", also known as the conventional corneal cross-linking approach, should be used to halt the progression of keratoconus in young patients. However, if the procedure needs to be completed more rapidly, accelerated corneal crosslinking may be considered. Transepithelial corneal cross-linking has been proven to be less effective at stabilizing keratoconus, although being more safer.
Collapse
Affiliation(s)
- Pawan Prasher
- Department of Ophthalmology, Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, Punjab, India
| | - Ashok Sharma
- Cornea Centre, SCO 2463 - 2464, Sector 22 C, 160022, Chandigarh, India
| | - Rajan Sharma
- Cornea Centre, SCO 2463 - 2464, Sector 22 C, 160022, Chandigarh, India
| | - Vipan K. Vig
- Amritsar Eye Hospital, GNDU Shopping Complex, Amritsar, Punjab, India
| | | |
Collapse
|
18
|
Abdel-Radi M, Abdelmohsen N, Abdelmotaal H, Abd El-Moneim MT. The effect of accelerated pulsed high-fluence corneal cross-linking on corneal endothelium; a prospective specular microscopy study. BMC Ophthalmol 2023; 23:163. [PMID: 37072730 PMCID: PMC10114460 DOI: 10.1186/s12886-023-02912-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 04/07/2023] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND Corneal collagen cross-linking (CXL) is a procedure utilized for halting keratoconus progression with different approved protocols. The current study aimed to assess the corneal endothelial changes following the relatively new accelerated pulsed high-fluence protocol of epithelium-off corneal cross-linking for the treatment of mild to moderate keratoconus. METHODS This prospective case series study enrolled 45 eyes of 27 patients with mild to moderate progressive keratoconus who underwent accelerated pulsed high-fluence CXL (pl-ACXL, 30 mW/ cm2 UVA at 365 nm wavelength, 8 min pulsed mode 1 s on / 1 s off with a total energy of 7.2 J/ cm2). The main outcome measures were corneal endothelial changes assessed by specular microscopy at 3 and 6 months postoperatively including endothelial cell density (ECD), coefficient of variation, percentage of hexagonal cells, average, minimum and maximum endothelial cell sizes. Demarcation line depth was assessed 1 month following surgery. RESULTS The mean age of the studied sample was 24.89 ± 7.21. The mean preoperative ECD (2944.6 ± 247.41 cell/mm2) showed non-significant reduction at 3 and 6 months postoperatively (2931.03 ± 253.82 and 2924.7 ± 224.88 cell/mm2, respectively, P-value = 0.361). There were no significant changes in the mean coefficient of variation, percentage of hexagonal cells, average, minimum and maximum endothelial cell sizes at 3 and 6 months following pl-ACXL (P-value > 0.05). The mean demarcation line depth 1 month after pl-ACXL was 214 ± 17.43 μm. CONCLUSIONS Corneal endothelial changes following accelerated pulsed high-fluence CXL were minimal with stability of endothelial cell count and non-significant morphological changes. TRIAL REGISTRATION Clinicaltrials.gov: NCT04160338 (13/11/2019).
Collapse
Affiliation(s)
- Mahmoud Abdel-Radi
- Department of Ophthalmology, Assiut University, Assiut University Hospital 6th floor, Assiut, 71516, Egypt.
| | - Naglaa Abdelmohsen
- Department of Ophthalmology, Assiut University, Assiut University Hospital 6th floor, Assiut, 71516, Egypt
| | - Hazem Abdelmotaal
- Department of Ophthalmology, Assiut University, Assiut University Hospital 6th floor, Assiut, 71516, Egypt
| | | |
Collapse
|
19
|
Blaser F, Zweifel S, Wiest MRJ, Bajka A, Said S, Barthelmes D, Muth DR. Severe Complications after Corneal Collagen Cross-Linking (CXL). Klin Monbl Augenheilkd 2023; 240:369-378. [PMID: 37164391 PMCID: PMC10129411 DOI: 10.1055/a-2040-4290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 01/22/2023] [Indexed: 05/12/2023]
Abstract
PURPOSE To present a case series of rare and severe complications after corneal collagen cross-linking (CXL) of keratoconus patients. METHODS Single-center descriptive case series covering the period of 2012 to 2022 at the Department of Ophthalmology at the University Hospital, Zurich, Switzerland. RESULTS We present four eyes of four patients that showed severe unusual complications within the first month after CXL. Three patients had been treated with the classical epithelium-off "Dresden" protocol. One patient had been treated with the accelerated epithelium-off protocol. One patient presented with extensive corneal edema due to rubbing the eye after treatment. Two patients showed a bacterial infectious keratitis: one due to Streptococcus pneumoniae and the other due to Staphylococcus hominis, Micrococcus luteus, and Streptococcus epidermidis. The latter of the two patients exhibited extensive infectious crystalline keratopathy. The fourth patient showed a severe ulcerative lesion where no infectious cause could be found. Therefore, an autoimmune keratolytic process had to be suspected. Apart from the corneal edema, which resolved ad integrum, the other complications resulted in permanent corneal scarring and thinning. One patient needed an emergency amniotic transplant. CONCLUSION Severe complications after CXL remain rare. Most common causes are complications that are not directly associated with the treatment as such. Those indirect complications occur after the treatment during the healing course of the epithelium. Associations with bandage contact lenses, topical steroids, atopic disease, and inappropriate patient behavior are often suspected. Correctly performed corneal scrapings with repeated microbiological analysis and a detailed patient history are essential for establishing the correct diagnosis, especially in complicated cases that do not respond to a standard therapeutic regimen. This case series supports the efforts that are currently taken to improve the CXL technique in a way that postoperative complications are further reduced. A more efficient epithelium-on technique might be a step in that direction.
Collapse
Affiliation(s)
- Frank Blaser
- Ophthalmology and Eye Clinic, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Sandrine Zweifel
- Ophthalmology and Eye Clinic, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Anahita Bajka
- Ophthalmology and Eye Clinic, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Sadiq Said
- Ophthalmology and Eye Clinic, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Daniel Barthelmes
- Ophthalmology and Eye Clinic, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Daniel Rudolf Muth
- Ophthalmology and Eye Clinic, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
20
|
Yang Q, Wang S, He Y, Zhang Y. The research progress on the molecular mechanism of corneal cross-linking in keratoconus treatment. Cont Lens Anterior Eye 2023; 46:101795. [PMID: 36549953 DOI: 10.1016/j.clae.2022.101795] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022]
Abstract
Keratoconus (KC) is a corneal anomaly that is manifested in a limited cone-like bulge with corneal thinning. Many molecules in the cornea change during the development of KC, including various components of the extracellular matrix, cytokines, cell connection, and cell adhesion-related proteins. Several treatment options are available, with corneal cross-linking (CXL) being the treatment of choice for early KC. However, postoperative complications have been reported in some CXL patients, mainly caused by corneal epithelial resection. Despite the fact that some novel approaches have helped to reduce some of the initial post-operative issues, their effectiveness seems to be inferior to that of the original CXL. To keep effectiveness while avoiding these negative effects, it is necessary to study the mechanism of CXL in KC treatment at the molecular level. This article provides a review of the molecular mechanism of CXL in the treatment of KC from four aspects: enzyme activity, signal transduction pathway, corneal-related proteins, and other KC-related molecules, further confirming the feasibility of CXL treatment of KC, providing new ideas for improving CXL.
Collapse
Affiliation(s)
- Qingyu Yang
- Department of Ophthalmology, 2nd Hospital of Jilin University, Changchun 130041, China.
| | - Shurong Wang
- Department of Ophthalmology, 2nd Hospital of Jilin University, Changchun 130041, China.
| | - Yuxi He
- Department of Ophthalmology, 2nd Hospital of Jilin University, Changchun 130041, China
| | - Yan Zhang
- Department of Ophthalmology, 2nd Hospital of Jilin University, Changchun 130041, China.
| |
Collapse
|
21
|
Muacevic A, Adler JR. A Comparison Between Cross-Linking Protocols in Patients With Progressive Keratoconus: A Review. Cureus 2022; 14:e31029. [PMID: 36475196 PMCID: PMC9718644 DOI: 10.7759/cureus.31029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2022] [Indexed: 01/25/2023] Open
Abstract
Keratoconus (KC) is a noninflammatory cornea disease leading to progressive thinning, causing it to change from its normal dome shape to a cone shape. One of the novel treatments of KC is corneal collagen cross-linking (CXL). Due to its importance, many studies have been conducted to compare corneal cross-linking protocols; this review article aims to discuss corneal cross-linking and compare its different treatment options, including Dresden, accelerated, and customized protocols in patients with progressive KC and their respective long-term outcomes. A search was performed in PubMed and Google Scholar with no language, dates, or study type restriction. Most of the results showed almost no difference between protocols over traditional cross-linking. However, published data are limited, long-term outcomes of novel age groups remain unclear, and further studies are needed.
Collapse
|
22
|
Wang L, Deng Y, Ma K, Yin H, Sun C, Tang J. Herpetic Keratitis Following Corneal Crosslinking for Keratoconus: A Case Series. Infect Drug Resist 2022; 15:6555-6562. [PMID: 36386417 PMCID: PMC9656390 DOI: 10.2147/idr.s389920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/02/2022] [Indexed: 11/10/2022] Open
Abstract
Background Corneal crosslinking is widely applied to enhance corneal biomechanical properties and delay the progression of keratoconus. The surgical procedure and application of ultraviolet A irradiation (UVA) during corneal crosslinking have been recognized to induce the reactivation of simplex herpes virus (HSV) but are rarely reported and poorly analyzed. Case Presentation We report the first case series of herpetic keratitis in 4 keratoconus patients undertaking corneal crosslinking, who were all clinically diagnosed at routine follow-up visits 3 days to 1 month after the surgery. Different from the typical new onset of secondary herpetic keratitis that mainly presents with epithelial lesions and severe eye pain, these patients all presented with stromal infiltrates and were generally asymptomatic except for vision blurring in 2 patients. All patients responded well to antiviral therapy, topical steroids, and epithelial nourishment medication, leaving corneal macula or nebula at the last follow-up visit. Conclusion Close follow-up is essential and the most effective way to diagnose herpetic keratitis after corneal crosslinking due to the lack of subjective symptoms. The prophylactic use of antiviral therapy on asymptomatic patients is controversial and should be evaluated based on long-term prognosis.
Collapse
Affiliation(s)
- Lixiang Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Yingping Deng
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Ke Ma
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Hongbo Yin
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Chengshu Sun
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Jing Tang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
- Correspondence: Jing Tang, Department of Ophthalmology, West China Hospital of Sichuan University, No.37, Guoxue Alley, Sichuan, People’s Republic of China, Tel +86 18980603835, Email
| |
Collapse
|
23
|
Akram S, Momin S, Malik B, Sirang Z. Outcomes of Epi-On Collagen Cross-Linkage Procedure Assessed in Progressive Keratoconus Patients. Cureus 2022; 14:e30664. [DOI: 10.7759/cureus.30664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2022] [Indexed: 11/06/2022] Open
|
24
|
Borchert GA, Watson SL, Kandel H. Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis. Asia Pac J Ophthalmol (Phila) 2022; 11:453-459. [PMID: 36094374 DOI: 10.1097/apo.0000000000000555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/17/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Keratoconus is a disorder that results in visual loss from increased corneal high-order aberrations and irregular astigmatism and reduces quality of life. The primary treatment for progressive keratoconus is crosslinking (CXL). Recently, it has been suggested that oxygen enhances the type II photodynamic reaction of CXL that is oxygen dependent. Our study investigated the effect of increased oxygen availability in epithelium-on CXL on visual acuity and corneal curvature. METHODS We searched PubMed, EMBASE, Medline, Web of Science, and Scopus databases on November 3, 2021. We included studies that reported increased oxygen availability during CXL in patients with keratoconus published within the last 10 years. A meta-analysis on the primary outcomes, maximum keratometry, and corrected distance visual acuity, was conducted. RESULTS The search yielded 108 publications which were screened and assessed for eligibility. Six studies were included in the systematic review and 5 studies were included in our meta-analysis of the outcomes of increased oxygen availability in accelerated CXL. The meta-analysis on data after 6 months of follow-up found a significant decrease in mean maximum keratometry of 1.2 diopter (95% confidence interval: 0.2-2.3; P =0.02) and an improvement in mean corrected distance visual acuity by 0.08 logMAR (95% confidence interval, 0.02-0.13; P =0.01). There were no serious adverse events reported. CONCLUSIONS Increasing oxygen during epithelium-on CXL improved visual acuity and produced corneal flattening without any serious adverse events in patients with keratoconus. The demarcation line depth was significantly higher with oxygen compared to the control group. Further data are required with a control group and long-term follow-up across a range of CXL protocols for implementation into standard clinical practice.
Collapse
Affiliation(s)
- Grace A Borchert
- Save Sight Institute, Discipline of Ophthalmology, The University of Sydney, Sydney, Australia
| | | | | |
Collapse
|
25
|
Gouldin AG, Brown ME, Puetzer JL. An inducible model for unraveling the effects of advanced glycation end-product accumulation in aging connective tissues. Connect Tissue Res 2022; 63:406-424. [PMID: 34706612 DOI: 10.1080/03008207.2021.1991333] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE In connective tissues there is a clear link between increasing age and degeneration. Advanced glycation end-products (AGEs) are believed to play a central role. AGEs are sugar-induced non-enzymatic crosslinks which accumulate in collagen with age and diabetes, altering tissue mechanics and cellular function. Despite ample correlative evidence linking collagen glycation to tissue degeneration, little is known how AGEs impact cell-matrix interactions, limiting therapeutic options. One reason for this limited understanding is that AGEs are typically induced using high concentrations of ribose which decrease cell viability, making it impossible to investigate cell-matrix interactions. The objective of this study was to develop a system to trigger AGE accumulation while maintaining cell viability. MATERIALS AND METHODS Using cell-seeded high density collagen gels, we investigated the effect of two systems for AGE induction, ribose at low concentrations (30, 100, and 200 mM) over 15 days of culture and riboflavin (0.25 and 0.75 mM) induced with blue light for 40 seconds (riboflavin-465 nm). RESULTS We found ribose and riboflavin-465 nm treatment produces fluorescent AGE quantities which match and/or exceed human fluorescent AGE levels for various tissues, ages, and diseases, without affecting cell viability or metabolism. Interestingly, a 40 second treatment of riboflavin-465 nm produced similar levels of fluorescent AGEs as 3 days of 100 mM ribose treatment. CONCLUSIONS Riboflavin-465 nm is a promising method to trigger AGEs on demand in vivo or in vitro without impacting cell viability and offers potential for unraveling the mechanism of AGEs in age and diabetes related tissue damage.
Collapse
Affiliation(s)
- Austin G Gouldin
- Departments of Biomedical Engineering; Orthopaedic Surgery, Virginia Commonwealth University, Richmond, Virginia, United States
| | - M Ethan Brown
- Departments of Biomedical Engineering; Orthopaedic Surgery, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Jennifer L Puetzer
- Departments of Biomedical Engineering; Orthopaedic Surgery, Virginia Commonwealth University, Richmond, Virginia, United States
| |
Collapse
|
26
|
Xanthopoulou K, Milioti G, Daas L, Munteanu C, Seitz B, Flockerzi E. Accelerated corneal crosslinking causes pseudoprogression in keratoconus within the first 6 weeks without affecting posterior corneal curvature. Eur J Ophthalmol 2022; 32:2565-2576. [PMID: 35535408 DOI: 10.1177/11206721221099257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To evaluate the effectiveness of epithelium-off (epi-off) accelerated corneal crosslinking (A-CXL, 9 mW/cm2, 10 min) in adult keratoconus (KC) patients. METHODS The study included 151 KC corneas (124 patients) after A-CXL. The parameters best corrected visual acuity (BCVA) and the tomographic readings (Pentacam HR, Oculus, Germany) were analysed at 24, 12 and 6 months preoperatively, prior to surgery; and 6 weeks, 6 months, 1, 2 and >2 years postoperatively. The demarcation line was assessed by anterior segment optical coherence tomography (Tomey SS-1000, CASIA 2 (Tomey, Nagoya, Japan)). RESULTS Comparing pre- to postoperative findings 6 weeks after A-CXL with paired t-test, the anterior steep (46.8 ± 4.0|47.1 ± 4.1), flat (50.2 ± 4.3|50.6 ± 4.6) and maximal keratometry (57.6 ± 6.8|58.3 ± 6.8) increased (p < 0.05), while the thinnest pachymetry decreased significantly (459 ± 39|444 ± 42, p < 0.05). Lateron, however, there was a decreasing anterior flat (1, 2 and >2 years; p < 0.0001), mean (1 year; p = 0.01 and 2 years; p = 0.03) and maximal keratometry (1, 2 and >2 years; p < 0.0001). The posterior corneal keratometry readings did not change significantly until >2 years after A-CXL (MANOVA; steep, p = 0.008; flat, p = 0.027; mean, p = 0.007). The mean depth of the demarcation line was 242 ± 62 µm (53.6%). The preoperative logMAR BCVA (0.35 ± 0.02) decreased 6 weeks after A-CXL (0.39 ± 0.03) followed by a continuous improvement until the latest follow-up (0.18 ± 0.04). CONCLUSION A-CXL constitutes a successful method for KC stabilization. Signs of KC progression occur within the first 6 weeks postoperatively ("pseudoprogression"), but this is not indicative of the long-term effect.
Collapse
Affiliation(s)
| | - Georgia Milioti
- Department of Ophthalmology, 39072Saarland University Medical Center, Homburg, Germany
| | - Loay Daas
- Department of Ophthalmology, 39072Saarland University Medical Center, Homburg, Germany
| | - Cristian Munteanu
- Department of Ophthalmology, 39072Saarland University Medical Center, Homburg, Germany
| | - Berthold Seitz
- Department of Ophthalmology, 39072Saarland University Medical Center, Homburg, Germany
| | - Elias Flockerzi
- Department of Ophthalmology, 39072Saarland University Medical Center, Homburg, Germany
| |
Collapse
|
27
|
Gassel CJ, Röck D, Konrad EM, Blumenstock G, Bartz-Schmidt KU, Röck T. Impact of keratoconus stage on outcome after corneal crosslinking. BMC Ophthalmol 2022; 22:207. [PMID: 35524196 PMCID: PMC9077944 DOI: 10.1186/s12886-022-02425-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 04/22/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This study aimed to analyze if the outcome after corneal crosslinking (CXL) in progressive keratoconus patients depends on the stage at which the procedure is performed. This knowledge would help to improve success of CXL and to define surgery indications in those patients. METHODS In this retrospective study, 124 consecutive eyes of 100 patients with progressive keratoconus undergoing corneal CXL at the University Eye Hospital Tübingen were included. The eyes were graded according to modified Krumeich stages depending on induced myopia or astigmatism, corneal radii, minimum corneal thickness, and morphological changes. The observation period covered November 2008 to September 2018. Preoperatively, 12 and 24 months after CXL, the best corrected visual acuity (BCVA) was determined and astigmatism as well as tomographic parameters (Kmax, Kmin, central corneal thickness (CCT), minimum corneal thickness (MCT)) were measured by means of a Scheimpflug camera system. RESULTS BCVA results showed significant differences between the modified Krumeich stages at 12 months (p = 0.014) and at 24 months postoperatively (p = 0.032). Also, astigmatism differed significantly among the stages at 24 months after CXL (p = 0.023). However, no significant differences regarding astigmatism were detectable after 12 months. In terms of Kmax, Kmin, CCT, and MCT, no significant differences between the Krumeich stages were observed. CONCLUSIONS BCVA showed a significantly higher improvement after CXL in the early stage of keratoconus compared to a higher stage. However, the postinterventional tomographic values did not differ significantly between the different modified Krumeich stages. The significantly higher improvement in BCVA after CXL in the early stage might indicate that earlier intervention provides a higher subjective benefit to the individual. Further studies with larger sample sizes are needed to confirm these findings.
Collapse
Affiliation(s)
- Caroline Julia Gassel
- Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany
| | - Daniel Röck
- Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany
| | - Eva-Maria Konrad
- Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany
| | - Gunnar Blumenstock
- Institute for Clinical Epidemiology and Applied Biometry, Eberhard Karls University Tübingen, Silcherstr. 5, 72076, Tübingen, Germany
| | - Karl Ulrich Bartz-Schmidt
- Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany
| | - Tobias Röck
- Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany.
| |
Collapse
|
28
|
Qin X, Tian L, Zhang H, Zhang D, Jie Y, Zhang HX, Li L. Determine Corneal Biomechanical Parameters by Finite Element Simulation and Parametric Analysis Based on ORA Measurements. Front Bioeng Biotechnol 2022; 10:862947. [PMID: 35497338 PMCID: PMC9043460 DOI: 10.3389/fbioe.2022.862947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/23/2022] [Indexed: 11/14/2022] Open
Abstract
Purpose: The Ocular Response Analyzer (ORA) is one of the most commonly used devices to measure corneal biomechanics in vivo. Until now, the relationship between the output parameters and corneal typical biomechanical parameters was not clear. Hence, we defined the output parameters of ORA as ORA output parameters. This study aims to propose a method to determine corneal biomechanical parameters based on ORA measurements by finite element simulation and parametric analysis. Methods: Finite element analysis was used to simulate the mechanics process of ORA measurements with different intraocular pressure (IOP), corneal geometrical parameters and corneal biomechanical parameters. A simplified geometrical optics model was built to simulate the optical process of the measurements to extract ORA output parameters. After that, 70% of the simulated data was used to establish the quantitative relationship between corneal biomechanical parameters and ORA output parameters by parametric analysis and 30% of the simulated data was used to validate the established model. Besides, ten normal subjects were included to evaluate the normal range of corneal biomechanical parameters calculated from ORA. Results: The quantitative relationship between corneal biomechanical parameters and ORA output parameters is established by combining parametric analysis with finite element simulation. The elastic modulus (E) and relaxation limit (G∞) of the ten normal subjects were 0.65 ± 0.07 MPa and 0.26 ± 0.15, respectively. Conclusions: A method was proposed to determine corneal biomechanical parameters based on the results of ORA measurements. The magnitude of the corneal biomechanical parameters calculated according to our method was reasonable.
Collapse
Affiliation(s)
- Xiao Qin
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- Medical Science Research Center, Department of Otolaryngology, Peking Union Medical College Hospital, Shuaifuyuan 1, Dongcheng District, Beijing, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, China
| | - Hui Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Di Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Ying Jie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| | - Hai-Xia Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| | - Lin Li
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| |
Collapse
|
29
|
Comparison of Long-Term Outcomes and Refractive Stability following SMILE versus SMILE Combined with Accelerated Cross-Linking (SMILE XTRA). J Ophthalmol 2022; 2022:4319785. [PMID: 35265368 PMCID: PMC8901300 DOI: 10.1155/2022/4319785] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/28/2022] [Indexed: 11/18/2022] Open
Abstract
Purpose To compare the long-term safety, efficacy, predictability, and refractive stability following SMILE versus SMILE combined with accelerated cross-linking (SMILE XTRA), and to specifically study the regression patterns following the two procedures. Methods This retrospective study included 54 eyes of SMILE and 54 eyes of SMILE XTRA treated for normal and borderline cases of myopia/myopic astigmatism, respectively, based on certain predefined topographic features and risk factors. Patients in both the groups were matched for age and refractive error. The mean postoperative follow-up for the SMILE group was 22.18 ± 10.41 months and the SMILE XTRA group was 21.81 ± 10.19 months. Results At the end of follow-up, the mean sphere, cylinder, and SE reduced to −0.03, −0.09, and −0.08 D in the SMILE group and −0.06, −0.15, and −0.13 D in the SMILE XTRA group. 96% and 93% eyes remained within ±0.50 D in SMILE and SMILE XTRA groups, respectively, and 94% eyes maintained an UDVA of 20/20 or better in the SMILE as well as SMILE XTRA groups. Safety and efficacy indices for the SMILE group were 1.03 and 1.00. For the SMILE XTRA group, the safety and efficacy indices were 1.00 and 0.99. No eye in either group had postoperative ectasia or enhancement performed for significant residual refractive error. Conclusion Both the SMILE and SMILE XTRA groups exhibited comparable visual outcomes, safety, and efficacy. Contrary to the belief, combination of prophylactic CXL with SMILE did not result in a hyperopic shift in the long term. No eye in either group encountered postoperative ectasia; however, further follow-up is suggested to establish the long-term effects on refractive and corneal stability following SMILE XTRA, as all the eyes treated in this group were borderline.
Collapse
|
30
|
Wajnsztajn D, Shmueli O, Zur K, Frucht-Pery J, Solomon A. Predicting factors for the efficacy of cross-linking for keratoconus. PLoS One 2022; 17:e0263528. [PMID: 35113959 PMCID: PMC8812864 DOI: 10.1371/journal.pone.0263528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 01/20/2022] [Indexed: 11/19/2022] Open
Abstract
Purpose
To evaluate predictors for success in corneal crosslinking (CXL) for keratoconus in a large cohort and extended follow-up.
Design
A retrospective study based on a prospectively built database.
Methods
Participants underwent CXL for keratoconus from 2007 to 2018. Statistical analysis was performed for patients with at least 1-year follow-up. We analyzed effects of CXL type (Epithelium-on or Epithelium-off and Accelerated (9mW/cm2@10min) or Standard (3mW/cm2@30min)) and pre-operative factors including age, gender, baseline LogMAR visual acuity (LogMARpre), maximal corneal power (Kmaxpre), pachymetry, refractive and topographic cylinders, spherical equivalent (SEpre), mean corneal power (MeanK) and follow-up time on outcome measures. The outcome measures were the final change of Kmax (Delta Kmax) and the final change in LogMAR visual acuity (Delta LogMAR). A more negative Delta Kmax or Delta LogMAR represents a favorable effect of crosslinking.
Results
517 eyes had Kmax results, and 385 eyes had LogMAR results with more than one year follow-up. These eyes were included in the study. The mean follow-up time was 2.29 years. Mean Kmax decreased from 54.07±5.99 diopters to 52.84±5.66 diopters (p<0.001), and Mean LogMAR decreased from 0.28±0.20 to 0.25±0.21 (p<0.001). Non-accelerated epithelium-off CXL resulted in greater flattening of Kmax when compared with other protocols. Visual acuity improvement was similar when comparing different CXL protocols. Multivariate analysis showed four factors associated with negative Delta Kmax: high Kmaxpre, high SEpre, high MeanKpre, and non-accelerated procedure. Multivariate analysis showed three factors associated with negative Delta LogMAR: high LogMARpre, high SEpre, and Low MeanKpre. After excluding corneas with Kmaxpre >65 D or Pachymetry<400 microns, multivariate analysis showed that high Kmaxpre, high SEpre, and non-accelerated CXL were associated with negative Delta Kmax while high LogMARpre and high SEpre were associated with negative Delta LogMAR.
Conclusion
CXL for keratoconus is a highly effective treatment, as evident by its effects on the outcome measures: Delta Kmax and Delta LogMAR. CXL was more successful in eyes with high Kmaxpre, high SEpre, and high LogMARpre, which express disease severity. The non-accelerated epithelium-off protocol was associated with greater flattening of corneal curvature but did not show a better effect on visual acuity as compared to the other CXL protocols.
Collapse
Affiliation(s)
- Denise Wajnsztajn
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Or Shmueli
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ken Zur
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Joseph Frucht-Pery
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Abraham Solomon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
- * E-mail:
| |
Collapse
|
31
|
Yuan Z, Yu M, Li D, Zhang H, Li L. Protein expression changes in cornea after collagen crosslinking. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2022. [DOI: 10.1016/j.medntd.2022.100123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
32
|
Bhattacharyya A, Sarma P, Kaur H, Hafezi F, Bhattacharyya J, Kirubakaran R, Prajapat M, Medhi B, Das K, Prakash A, Singh A, Kumar S, Singh R, Reddy D, Kaur G, Sharma S. Short- and long-term safety and efficacy of corneal collagen cross-linking in progressive keratoconus: A systematic review and meta-analysis of randomized controlled trials. Taiwan J Ophthalmol 2022. [PMID: 37484615 PMCID: PMC10361434 DOI: 10.4103/2211-5056.361974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The purpose of the study is to evaluate the safety and outcomes of corneal collagen cross-linking (CXL) and different CXL protocols in progressive keratoconus (PK) population at short and long-term. MATERIALS AND METHODS A systematic review and meta-analysis was conducted. A total of eight literature databases were searched (up to February 15, 2022). Randomized controlled trials (RCTs) comparing CXL versus placebo/control or comparing different CXL protocols in the PK population were included. The primary objective was assessment of outcomes of CXL versus placebo and comparison of different CXL protocols in terms of maximum keratometry (Kmax) or Kmax change from baseline (Δ), spherical equivalent, best corrected visual acuity (BCVA), and central corneal thickness (CCT) in both at short term (6 months) and long term (1st, 2nd, and 3rd year or more). The secondary objective was comparative evaluation of safety. For the meta-analysis, the RevMan5.3 software was used. RESULTS A total of 48 RCTs were included. Compared to control, CXL was associated with improvement in Δ Kmax at 1 year (4 RCTs, mean difference [MD], -1.78 [-2.71, -0.86], P = 0.0002) and 2 and 3 years (1 RCT); ΔBCVA at 1 year (7 RCTs, -0.10 [-0.14, -0.06], P < 0.00001); and Δ CCT at 1 year (2 RCTs) and 3 years (1 RCT). Compared to conventional CXL (C-CXL), deterioration in Δ Kmax, ΔBCVA and endothelial cell density was seen at long term in the transepithelial CXL (TE-CXL, chemical enhancer). Up to 2 years, there was no difference between TE-CXL using iontophoresis (T-ionto) and C-CXL. At 2 and 4 years, C-CXL performed better compared to accelerated CXL (A-CXL) in terms of improving Kmax. Although CCT was higher in the A-CXL arm at 2 years, there was no difference at 4 years. While exploring heterogeneity among studies, selection of control eye (fellow eye of the same patient vs. eye of different patient) and baseline difference in Kmax were important sources of heterogeneity. CONCLUSION CXL outperforms placebo/control in terms of enhancing Kmax and CCT, as well as slowing disease progression over time (till 3 years). T-ionto protocol, on the other hand, performed similarly to C-CXL protocol up to 2 years.
Collapse
|
33
|
Brar S, Roopashree CR, Ganesh S. Incidence of Ectasia After SMILE From a High-Volume Refractive Surgery Center in India. J Refract Surg 2021; 37:800-808. [PMID: 34914554 DOI: 10.3928/1081597x-20210812-03] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE To report the incidence of ectasia after small incision lenticule extraction (SMILE) in a high-volume refractive surgery center in India. METHODS To derive the incidence of ectasia after SMILE, all eyes that underwent SMILE or SMILE Xtra (SMILE combined with prophylactic accelerated corneal cross-linking) from November 2012 to August 2019 were retrospectively analyzed. Furthermore, these cases were classified as being "normal" or "borderline" based on certain predefined criteria. Only eyes with a minimum follow-up of 12 months were included. RESULTS Of the total 7,024 eyes analyzed, 6,619 eyes underwent SMILE, of which 10 eyes developed ectasia at a mean interval of 21.3 months, making the incidence of ectasia after SMILE 0.15%. Of these 10 eyes with ectasia, 2 eyes had normal preoperative topography, whereas the remaining 8 eyes were borderline as per the predefined criteria. Retrospective data analysis revealed that 6,025 of 7,024 eyes were normal and thus suitable for a standard SMILE procedure, whereas 999 eyes were borderline, of which 594 eyes underwent SMILE and 405 eyes underwent SMILE Xtra. The incidence of ectasia in borderline eyes undergoing SMILE was 0.80% (8 of 999) versus 0% (none) for borderline eyes undergoing SMILE Xtra (chi square, P < .05). CONCLUSIONS The incidence of ectasia after SMILE in the early postoperative period was 0.15%, with borderline eyes accounting for most cases. Borderline eyes treated with SMILE Xtra did not progress to ectasia, potentially suggesting a protective role of simultaneous CXL. [J Refract Surg. 2021;37(12):800-808.].
Collapse
|
34
|
Wan MC, Qin W, Lei C, Li QH, Meng M, Fang M, Song W, Chen JH, Tay F, Niu LN. Biomaterials from the sea: Future building blocks for biomedical applications. Bioact Mater 2021; 6:4255-4285. [PMID: 33997505 PMCID: PMC8102716 DOI: 10.1016/j.bioactmat.2021.04.028] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 04/15/2021] [Accepted: 04/17/2021] [Indexed: 02/08/2023] Open
Abstract
Marine resources have tremendous potential for developing high-value biomaterials. The last decade has seen an increasing number of biomaterials that originate from marine organisms. This field is rapidly evolving. Marine biomaterials experience several periods of discovery and development ranging from coralline bone graft to polysaccharide-based biomaterials. The latter are represented by chitin and chitosan, marine-derived collagen, and composites of different organisms of marine origin. The diversity of marine natural products, their properties and applications are discussed thoroughly in the present review. These materials are easily available and possess excellent biocompatibility, biodegradability and potent bioactive characteristics. Important applications of marine biomaterials include medical applications, antimicrobial agents, drug delivery agents, anticoagulants, rehabilitation of diseases such as cardiovascular diseases, bone diseases and diabetes, as well as comestible, cosmetic and industrial applications.
Collapse
Affiliation(s)
- Mei-chen Wan
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Wen Qin
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Chen Lei
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Qi-hong Li
- Department of Stomatology, The Fifth Medical Centre, Chinese PLA General Hospital (Former 307th Hospital of the PLA), Dongda Street, Beijing, 100071, PR China
| | - Meng Meng
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Ming Fang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Wen Song
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Ji-hua Chen
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
| | - Franklin Tay
- College of Graduate Studies, Augusta University, Augusta, GA, 30912, USA
| | - Li-na Niu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, PR China
- The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan, 453000, PR China
| |
Collapse
|
35
|
van der Valk Bouman ES, Pump H, Borsook D, Severinsky B, Wisse RPL, Saeed HN, Moulton EA. Pain mechanisms and management in corneal cross-linking: a review. BMJ Open Ophthalmol 2021; 6:e000878. [PMID: 34901466 PMCID: PMC8633999 DOI: 10.1136/bmjophth-2021-000878] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 11/07/2021] [Indexed: 11/17/2022] Open
Abstract
Though corneal collagen cross-linking (CXL) is an increasingly available and effective treatment for keratoconus, few reports have considered its impact on pain-related physiology in depth. This comprehensive narrative review summarises mechanisms underlying pain in CXL and clinical care possibilities, with the goal of future improvement in management of CXL-related pain. Postoperative pain associated with CXL is largely due to primary afferent nerve injury and, to a smaller extent, inflammation. Chronification of pain after CXL has not been reported, even as long-term nerve damage without regeneration following standard CXL treatment is frequently observed. The lack of pain chronification may be due to the minimally invasive nature of the procedure, with its rapidly recovering superficial corneal wound, and to the positive anti-inflammatory changes of the tear film that have been described after CXL. Different CXL approaches have been developed, with the transepithelial epithelial-on technique (epi-on) associated with less postsurgical pain than the gold standard, epithelial-off technique (epi-off). After the first few days, however, the difference in pain scores and need for analgesics between epi-on and epi-off disappear. Patients experience relatively high-intensity pain the first few days post-CXL, and many strategies for acute pain control following CXL have been studied. Currently, no method of pain management is considered superior or universally accepted. Acute pain following CXL is a recognised and clinically significant side effect, but few CXL studies have systematically investigated postoperative pain and its management. This review aims to improve patient pain outcomes following this increasingly common procedure.
Collapse
Affiliation(s)
| | | | - David Borsook
- Brain and Eye Pain Imaging Lab, Pain and Affective Neuroscience Center, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Childrens Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Boris Severinsky
- Department of Ophthalmology, Emory Eye Center, Atlanta, Georgia, USA
| | - Robert PL Wisse
- Department of Ophthalmology, Univerisity Medical Center, Utrecht, The Netherlands
| | - Hajirah N Saeed
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - Eric A Moulton
- Brain and Eye Pain Imaging Lab, Pain and Affective Neuroscience Center, Department of Anesthesiology, Critical Care and Pain Medicine; Department of Ophthalmology, Boston Childrens Hospital, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
36
|
Karamichos D, Escandon P, Vasini B, Nicholas SE, Van L, Dang DH, Cunningham RL, Riaz KM. Anterior pituitary, sex hormones, and keratoconus: Beyond traditional targets. Prog Retin Eye Res 2021; 88:101016. [PMID: 34740824 PMCID: PMC9058044 DOI: 10.1016/j.preteyeres.2021.101016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022]
Abstract
"The Diseases of the Horny-coat of The Eye", known today as keratoconus, is a progressive, multifactorial, non-inflammatory ectatic corneal disorder that is characterized by steepening (bulging) and thinning of the cornea, irregular astigmatism, myopia, and scarring that can cause devastating vision loss. The significant socioeconomic impact of the disease is immeasurable, as patients with keratoconus can have difficulties securing certain jobs or even joining the military. Despite the introduction of corneal crosslinking and improvements in scleral contact lens designs, corneal transplants remain the main surgical intervention for treating keratoconus refractory to medical therapy and visual rehabilitation. To-date, the etiology and pathogenesis of keratoconus remains unclear. Research studies have increased exponentially over the years, highlighting the clinical significance and international interest in this disease. Hormonal imbalances have been linked to keratoconus, both clinically and experimentally, with both sexes affected. However, it is unclear how (molecular/cellular signaling) or when (age/disease stage(s)) those hormones affect the keratoconic cornea. Previous studies have categorized the human cornea as an extragonadal tissue, showing modulation of the gonadotropins, specifically luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Studies herein provide new data (both in vitro and in vivo) to further delineate the role of hormones/gonadotropins in the keratoconus pathobiology, and propose the existence of a new axis named the Hypothalamic-Pituitary-Adrenal-Corneal (HPAC) axis.
Collapse
Affiliation(s)
- Dimitrios Karamichos
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA.
| | - Paulina Escandon
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Brenda Vasini
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Sarah E Nicholas
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Lyly Van
- University of Oklahoma Health Sciences Center, 940 Stanton L Young, Oklahoma City, OK, USA; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Deanna H Dang
- College of Medicine, University of Oklahoma Health Sciences Center, 940 Stanton L Young, Oklahoma City, OK, USA
| | - Rebecca L Cunningham
- Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Kamran M Riaz
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| |
Collapse
|
37
|
Systemic supplemental oxygen therapy during accelerated corneal crosslinking for progressive keratoconus: randomized clinical trial. J Cataract Refract Surg 2021; 47:773-779. [PMID: 33252568 DOI: 10.1097/j.jcrs.0000000000000513] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/04/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE To investigate the potential additive effect of systemic supplemental oxygen administered during accelerated corneal crosslinking (CXL) for progressive keratoconus (KC). SETTING Academic center. DESIGN Randomized clinical trial. METHODS Eyes with progressive KC randomized to 3 different CXL protocols were included. The first group (OA-CXL) included 19 eyes that underwent an accelerated CXL protocol (9 mW/cm2 for 10 minutes) while receiving systemic oxygen at a rate of 5 L/min for 10 minutes. The second group consisted of 14 eyes undergoing the same accelerated CXL protocol without supplemental oxygen therapy (A-CXL). The third group (C-CXL) comprised 14 eyes undergoing conventional CXL according to the Dresden protocol. All subjects were followed up for at least 6 months. Visual acuity, keratometry and corneal biomechanical parameters including corneal hysteresis and corneal resistance factor (CRF) were measured preoperatively and 6 months postoperatively. RESULTS Reduction in maximum keratometry (Kmax) was significantly greater in the OA-CXL group (P = .01). At baseline, the mean Kmax was 54.31 ± 3.64 diopters (D) in the OA-CXL group, 54.66 ± 4.99 D in the A-CXL group, and 56.03 ± 5.28 D in the C-CXL group (P = .58), which reached 53.58 ± 3.24 D, 54.59 ± 4.65 D, and 55.87 ± 4.73 D at 6 months in the 3 study groups, respectively (P = .115). The mean CRF increased significantly only in the OA-CXL group from a baseline value of 6.32 ± 2.12 mm Hg to 7.38 ± 1.88 mm Hg at 6 months (P = .009). CONCLUSIONS This study suggests superior efficacy of an accelerated CXL protocol coupled with systemic oxygen supplementation when compared with the accelerated CXL protocol and the conventional protocol in eyes with progressive KC. In addition to greater reduction in Kmax as the primary outcome, improvement in corneal biomechanics was also observed at 6 months.
Collapse
|
38
|
Nozari N, Biazar E, Kamalvand M, Keshel SH, Shirinbakhsh S. Photo Cross-linkable Biopolymers for Cornea Tissue Healing. Curr Stem Cell Res Ther 2021; 17:58-70. [PMID: 34269669 DOI: 10.2174/1574888x16666210715112738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/11/2021] [Accepted: 03/28/2021] [Indexed: 11/22/2022]
Abstract
Light can act as an effective and strong agent for the cross-linking of biomaterials and tissues and is recognized as a safe substitute for chemical cross-linkers to modify mechanical and physical properties and promote biocompatibility. This review focuses on the research about cross-linked biomaterials with different radiation sources such as Laser or Ultraviolet (UV) that can be applied as scaffolds, controlled release systems, and tissue adhesives for cornea healing and tissue regeneration.
Collapse
Affiliation(s)
- Negar Nozari
- Tissue Engineering Group, Department of Biomaterials Engineering, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran
| | - Esmaeil Biazar
- Tissue Engineering Group, Department of Biomaterials Engineering, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran
| | - Mahshad Kamalvand
- Tissue Engineering Group, Department of Biomaterials Engineering, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran
| | - Saeed Heidari Keshel
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shervin Shirinbakhsh
- Tissue Engineering Group, Department of Biomaterials Engineering, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran
| |
Collapse
|
39
|
Dackowski EK, Logroño JB, Rivera C, Taylor N, Lopath PD, Chuck RS. Transepithelial Corneal Crosslinking Using a Novel Ultraviolet Light-Emitting Contact Lens Device: A Pilot Study. Transl Vis Sci Technol 2021; 10:5. [PMID: 34003974 PMCID: PMC8088220 DOI: 10.1167/tvst.10.5.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the feasibility of a novel, on-eye UVA light-emitting contact lens device driven by fiber optics for the corneal crosslinking (CXL) of patients with keratoconus. Methods In nine corneal transplant candidates with advanced keratoconus a scleral contact lens reservoir containing 0.007% benzalkonium chloride preserved with 0.25% riboflavin-monophosphate was placed on the eye for 30 minutes. The reservoir lens was removed and replaced with the CXLens UVA light-emitting contact lens. A 375-nm UVA light at 4 mW/cm2 intensity was delivered for 30 minutes for a dose of 7.2 J/cm2. A one-sided paired t-test was used to evaluate mean differences in maximum keratometry, thinnest corneal thickness, and endothelial cell density between screening and 6 months after CXL. A two-sided paired t-test was used to evaluate differences in best-corrected distance visual acuity between screening and 6 months after CXL. Results All patients received the treatment as per protocol and adhered to follow-up testing. At 6 months after CXL, treated eyes had an average −1.0 ± 1.6 diopters decrease in the maximum keratometry (P = 0.049), a nonsignificant 2.3 ± 7.5 letter improvement in best-corrected distance visual acuity (P = 0.19), a nonsignificant −17 ± 14 µm decrease in thinnest corneal thickness (P < 0.01), and a nonsignificant −86 ± 266 cells/mm2 decrease in endothelial cell density (P = 0.20). Conclusions Our pilot study demonstrated the feasibility of the novel CXL device for the treatment of keratoconus and indicates the device is ready for larger scale studies with longer follow-up periods. Translational Relevance The novel CXLens on-eye UVA light-emitting contact lens device offers the potential for efficient, high-throughput transepithelial corneal CXL.
Collapse
Affiliation(s)
| | - Juan Batlle Logroño
- Cornea and Refractive Surgery Laser Center, Santo Domingo, Dominican Republic
| | - Cristina Rivera
- Cornea and Refractive Surgery Laser Center, Santo Domingo, Dominican Republic
| | | | | | - Roy S Chuck
- Albert Einstein College of Medicine, Montefiore Medical Center, Department of Ophthalmology and Visual Sciences, New York, USA
| |
Collapse
|
40
|
Haneef A, Giridhara Gopalan RO, Rajendran DT, Nunes J, Kuppamuthu D, Radhakrishnan N, Young TH, Hsieh HY, Prajna NV, Willoughby CE, Williams R. Chemical Cross-Linking of Corneal Tissue to Reduce Progression of Loss of Sight in Patients With Keratoconus. Transl Vis Sci Technol 2021; 10:6. [PMID: 34003973 PMCID: PMC8088226 DOI: 10.1167/tvst.10.5.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We aimed to develop a novel chemical cross-linker treatment for keratoconus by reacting dicarboxylic acid spacer molecules and amine functional groups on protein structure of the tissue using carbodi-imide chemistry. We propose this as an alternative to conventional cross-linking treatment for keratoconus. Methods The study involved optimization of the cross-linker formulation. Mechanical stiffness of ex vivo porcine and human corneas after application of the cross-linker was measured. Histochemical analysis was performed to record changes in gross morphology after cross-linker treatment on ex vivo porcine and human and in vivo rabbit corneas. Terminal deoxynucleotidyl transferase-mediated dUTP-X nick-end-labeling (TUNEL) staining was performed to study apoptotic effects of cross-linker. Cytotoxicity potential of cross-linker was evaluated by studying explant cultures for cellular outgrowth and immunostaining assays on porcine and human corneas after treatment. Results We demonstrated a clinically relevant increase in stiffness in ex vivo experiments using porcine and human cornea without removal of corneal epithelium. Histological analysis showed no change in gross morphology of cornea and no evidence of apoptosis. In vivo treatment of rabbit eyes demonstrated initial thinning of corneal epithelium that recovered after seven days although with abnormal regularity of cells. Cellular outgrowth from corneal explant cultures after treatment further confirmed cell survival after treatment. Conclusions This chemical cross-linking of corneal tissue has potential advantages over current therapeutic options including lower cytotoxicity to stromal cells than ultraviolet A treatment. Translational Relevance The cross-linker has potential to become a treatment for keratoconus because it overcomes the need for procedures using specialized equipment and ensures accessibility to large populations.
Collapse
Affiliation(s)
- Atikah Haneef
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | | | | | - Jessica Nunes
- Aravind Medical Research Foundation, Madurai, Tamil Nadu, India
| | | | | | - Tai-Horng Young
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Hao-Ying Hsieh
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | | | - Colin E Willoughby
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Rachel Williams
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| |
Collapse
|
41
|
Aytekin E, Pehlivan SB. Corneal cross-linking approaches on keratoconus treatment. J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2021.102524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
42
|
Aydın E, Aslan MG. The efficiency and safety of oxygen-supplemented accelerated transepithelial corneal cross-linking. Int Ophthalmol 2021; 41:2993-3005. [PMID: 33876334 DOI: 10.1007/s10792-021-01859-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/08/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate the impact of oxygen delivery on the clinical outcomes of accelerated transepithelial corneal cross-linking (A-TE CXL). METHODS Fifty-seven eyes of 44 progressive keratoconus (KCN) patients were randomly separated into two age-sex-matched groups. Twenty-nine eyes of 23 KCN patients that underwent oxygen-supplemented A-TE CXL formed the study group and 28 eyes of 21 patients treated with the same procedure but under room air conditions formed the control group. All patients were examined preoperatively, one, six and twelve months after the procedure. The logMAR spectacle-corrected distance visual acuity (CDVA), maximum keratometry (Kmax), mean keratometry, apical posterior keratometry, cylindrical power, minimum central corneal thickness, keratoconus vertex front and back, ocular aberrations, endothelial cell density (ECD), demarcation line depth (DLD) and proportion measures were recorded for statistical analysis. RESULTS The preoperative, 1st, 6th and 12th months mean Kmax values of the study group were 55.14 ± 3.99D, 54.85 ± 3.82D, 54.37 ± 3.84D and 54.40 ± 3.86, respectively, and 54.47 ± 3.17D, 54.52 ± 2.97D, 54.25 ± 2.95D and 54.20 ± 2.97 in the control group. The mean Kmax value was decreased significantly more in the oxygen-supplemented group after 12 months compared to the control group (p = 0.019). The mean DLD was also significantly deeper in the study group (320 ± 17 µm) compared to the control group (269 ± 19 µm). There was no significant difference between the two groups in terms of ECD alterations at any of the time intervals (p > 0.05). CONCLUSION Keratoconus progression was significantly halted in both groups 12 months after the treatment. In addition, oxygen supplementation during A-TE CXL further significantly increased clinical outcomes compared to room air conditions without any significant change in ECD measures.
Collapse
Affiliation(s)
- Emre Aydın
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Rize, Turkey
| | - Mehmet Gökhan Aslan
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Rize, Turkey.
| |
Collapse
|
43
|
Mu X, Agostinacchio F, Xiang N, Pei Y, Khan Y, Guo C, Cebe P, Motta A, Kaplan DL. Recent Advances in 3D Printing with Protein-Based Inks. Prog Polym Sci 2021; 115:101375. [PMID: 33776158 PMCID: PMC7996313 DOI: 10.1016/j.progpolymsci.2021.101375] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Three-dimensional (3D) printing is a transformative manufacturing strategy, allowing rapid prototyping, customization, and flexible manipulation of structure-property relationships. Proteins are particularly appealing to formulate inks for 3D printing as they serve as essential structural components of living systems, provide a support presence in and around cells and for tissue functions, and also provide the basis for many essential ex vivo secreted structures in nature. Protein-based inks are beneficial in vivo due to their mechanics, chemical and physical match to the specific tissue, and full degradability, while also to promoting implant-host integration and serving as an interface between technology and biology. Exploiting the biological, chemical, and physical features of protein-based inks can provide key opportunities to meet the needs of tissue engineering and regenerative medicine. Despite these benefits, protein-based inks impose nontrivial challenges to 3D printing such as concentration and rheological features and reconstitution of the structural hierarchy observed in nature that is a source of the robust mechanics and functions of these materials. This review introduces photo-crosslinking mechanisms and rheological principles that underpins a variety of 3D printing techniques. The review also highlights recent advances in the design, development, and biomedical utility of monolithic and composite inks from a range of proteins, including collagen, silk, fibrinogen, and others. One particular focus throughout the review is to introduce unique material characteristics of proteins, including amino acid sequences, molecular assembly, and secondary conformations, which are useful for designing printing inks and for controlling the printed structures. Future perspectives of 3D printing with protein-based inks are also provided to support the promising spectrum of biomedical research accessible to these materials.
Collapse
Affiliation(s)
- Xuan Mu
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Francesca Agostinacchio
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- Department of Industrial Engineering, University of Trento, via Sommarive 9, Trento 38123, Italy
| | - Ning Xiang
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Ying Pei
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Yousef Khan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Chengchen Guo
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Peggy Cebe
- Department of Physics and Astronomy, Tufts University, Medford, MA 02155, USA
| | - Antonella Motta
- Department of Industrial Engineering, University of Trento, via Sommarive 9, Trento 38123, Italy
| | - David L. Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| |
Collapse
|
44
|
Altinbay D, Taskin I. The Effectiveness of Corneal Epithelial Debridement Performed with an Alcohol-Impregnated Sponge. Klin Monbl Augenheilkd 2021; 239:185-190. [PMID: 33733442 DOI: 10.1055/a-1327-3156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To evaluate the clinical outcomes of patients who underwent corneal surgery with debridement of epithelium by localised application of an alcohol-impregnated sponge instead of the usual alcohol reservoir method. DESIGN This study retrospectively included 52 eyes of 27 patients who underwent LASEK (laser-assisted subepithelial keratectomy) and CXL (cross-linking) surgery after application of this alcohol-assisted debridement method between January 2019 and April 2019. PARTICIPANTS Twenty-four patients who underwent LASEK and three patients who underwent CXL surgery were included in this study, which comprised a total of 52 eye operations. METHODS Epithelial debridement was performed after placing a 20% ethanol-impregnated sponge on the cornea for 20 seconds. RESULTS The mean pachymetry value was 509.40 ± 30.37 µm, the mean preoperative spherical equivalent was - 2.14 ± 1.02 dioptres, and the highest myopia and astigmatism values were - 4.25 dioptres and - 2.75 dioptres, respectively. It was seen that the corneal epithelium was completely and easily debrided in a size identical to that of the applied sponge. CONCLUSIONS Complete debridement of the corneal epithelium can be performed quickly, safely, and easily with this specially prepared sponge.
Collapse
|
45
|
Tzamalis A, Diafas A, Vinciguerra R, Ziakas N, Kymionis G. Repeated Corneal Cross-linking (CXL) in Keratoconus Progression After Primary Treatment: Updated Perspectives. Semin Ophthalmol 2021; 36:523-530. [PMID: 33656958 DOI: 10.1080/08820538.2021.1893762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Background: Corneal collagen cross-linking (CXL) has recently become the preferred practice in the management of progressive keratoconus and other corneal ectasias as it has been proven to be successful in halting progression of the disease with an excellent safety and efficacy profile. However, there is a known variation regarding the response to CXL, depending on several parameters related either to the treatment protocol, patient characteristics, or corneal biomechanical properties. In fact, continuing progression of keratoconus has been noted in some cases despite prior treatment with CXL.Methods: The aim of this article is to provide an updated review of all published results on repeated-CXL, focusing on the indications and the efficacy of repeated treatment and highlighting possible explanations of progression after primary CXL. Conclusions: The diagnosis of primary treatment failure should always be made based on specific clinical and imaging criteria, with repeated and consistent measurements, in order to exclude pseudoprogression. In cases of confirmed progression, physicians need to decide whether repeating CXL could be an option to enhance corneal stability without any complications.
Collapse
Affiliation(s)
- Argyrios Tzamalis
- 2nd Department of Ophthalmology, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece
| | - Asterios Diafas
- 2 Department of Ophthalmology, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece
| | | | - Nikolaos Ziakas
- 2 Department of Ophthalmology, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece
| | - George Kymionis
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile Des Aveugles, Switzerland
| |
Collapse
|
46
|
Toro-Giraldo L, Morales Flores N, Santana-Cruz O, Ramirez-Miranda A, Navas A, Olivo-Payne A, Lichtinger A, Jimenez-Corona A, Graue-Hernández EO. Cool Crosslinking: Riboflavin at 4°C for Pain Management After Crosslinking for Keratoconus Patients, A Randomized Clinical Trial. Cornea 2021; 40:1-4. [PMID: 33264161 DOI: 10.1097/ico.0000000000002484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To explore corneal cooling as a method of pain management in corneal-accelerated collagen cross-linking. METHODS This was a prospective and interventional randomized clinical trial registered in the National Institutes of Health Clinical Trials through the identifier NCT030760770. The research was conducted at the Institute of Ophthalmology "Conde de Valenciana." A total of 98 patients were randomly assigned to one of the following 2 groups: cold riboflavin (4°C) group or control group (riboflavin at room temperature). The inclusion criteria were patients of any sex, older than 18 years of age with keratoconus diagnosis who needed management with cross-linking in both eyes because of the evidence of progression. The exclusion criteria were patients who had cross-linking without epithelial debridement, unilateral cross-linking, or any other ocular pathologies besides keratoconus and any cognitive incapacity that would make the understanding of the pain test difficult. The main outcome measures were pain, tearing, photophobia, foreign body sensation, and irritation. RESULTS At 2 hours post-op, pain in the case and control groups was 3.80 ± 3.00 and 8.08 ± 2.21 (P < 0.05), tearing was 1.56 ± 1.96 and 8.29 ± 2.42 (P < 0.05), photophobia was 5.44 ± 3.57 and 7.83 ± 2.64 (P < 0.05), foreign body sensation was 2.20 ± 2.78 and 6.54 ± 2.73 (P < 0.05), and irritation was 3.48 ± 2.98 and 6.79 ± 3.00 (P < 0.05), respectively. A statistical significant difference was maintained in pain values on day 1 (2.79 ± 3.09 and 4.91 ± 3.27 [P < 0.05]), 2 (2.54 ± 2.41 and 4.00 ± 2.43 [P < 0.05]), and 4 (0.45 ± 0.76 and 1.22 ± 1.67 [P < 0.05]). CONCLUSIONS This study demonstrated that pain and associated symptoms decreased significantly in the riboflavin 4°C group.
Collapse
Affiliation(s)
- Laura Toro-Giraldo
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Norma Morales Flores
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Omar Santana-Cruz
- Department of Optometry, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico; and
| | - Arturo Ramirez-Miranda
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Alejandro Navas
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Andrew Olivo-Payne
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Alejandro Lichtinger
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Aida Jimenez-Corona
- Department of Ocular Epidemiology and Public Health, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| | - Enrique O Graue-Hernández
- Department of Cornea, External Disease and Refractive Surgery, Institute of Ophthalmology "Conde de Valenciana," Mexico City, Mexico
| |
Collapse
|
47
|
Brar S, Gautam M, Sute SS, Ganesh S. Refractive surgery with simultaneous collagen cross-linking for borderline corneas - A review of different techniques, their protocols and clinical outcomes. Indian J Ophthalmol 2020; 68:2744-2756. [PMID: 33229650 PMCID: PMC7856924 DOI: 10.4103/ijo.ijo_1709_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Simultaneous corneal cross-linking (CXL) has been proposed as an adjunct therapy to corneal refractive procedures to prevent future ectasia, especially when performed in borderline corneas. This review analyses the currently available literature (minimum follow-up 6 months) on corneal refractive surgery and simultaneous CXL (PRK Xtra, LASIK Xtra, and SMILE Xtra) to evaluate the overall results including the safety, efficacy, and potential complications associated with these procedures. A comprehensive literature search of various electronic databases (PubMed, PubMed Central, Cochrane database, and MEDLINE) was performed up to 20th May 2020. Four relevant studies were found for PRK Xtra, 12 for LASIK Xtra, and 3 for SMILE Xtra. The total number of eyes included in this review was 1,512: 294 for PRK Xtra, 221 for PRK-only, 446 eyes for LASIK Xtra, 398 eyes for LASIK-only, 91 for SMILE Xtra and 62 for SMILE-only. Current literature suggests that refractive surgery and simultaneous CXL is generally safe and delivers comparable results in terms of visual and refractive outcomes than refractive surgery alone. However, there is no consensus on a standard cross-linking protocol, and complications such as diffuse lamellar keratitis, central toxic keratopathy, and corneal ectasia following Xtra procedures have been reported. It is therefore suggested that surgeons exercise caution in case-selection and counsel their patients regarding the potential risks and benefits with Xtra procedures. Also, further studies are required to standardize the UV-A irradiation protocols and to evaluate the long-term effect on safety, refractive predictability, and stability of these procedures.
Collapse
Affiliation(s)
- Sheetal Brar
- Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
| | - Megha Gautam
- Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
| | - Smith Snehal Sute
- Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
| | - Sri Ganesh
- Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
| |
Collapse
|
48
|
Accuracy of the posterior corneal elevation values of Pentacam HR from different reference surfaces in early ectasia diagnosis. Int Ophthalmol 2020; 41:629-638. [PMID: 33095345 DOI: 10.1007/s10792-020-01618-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 10/05/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE Detecting the accuracy of various posterior elevation (PE) indices of Pentacam HR, and correlating them with some possibly related factors or parameters, in a cohort with early keratoconus (KC). METHODS A cross sectional study that was conducted at Eye World Hospital, Egypt. One hundred and two corneas were enrolled, including two groups; group 1 (50 corneas) having forme fruste or early KC, and group 2 (52 corneas) for healthy controls. Corneas were scanned using Pentacam HR (Oculus, Wetzlar, Germany). The investigated PE parameters were: PE from best fit sphere (BFS), PE from best fit toric ellipsoid (BFTE), PE from exclusion map of Belin Ambrosio's display (BAD), and PE from difference map of BAD. The four PE values were correlated to age, thinnest corneal thickness "TCT," posterior aberrations, and posterior Q value. RESULTS All the investigated indices were significantly different in group 1 compared to group 2 (p < 0.001). Accuracy of PE parameters revealed the highest AUROC for PE from BFTE (AUROC = 0.989, and best cutoff > 4 um with sensitivity 96.00% and specificity 96.15%). PE from difference map was the least accurate. Correlation coefficients showed a significant correlation between all the studied PE parameters and some of the posterior aberrations (root mean square of higher order aberrations, vertical coma, and spherical aberrations), besides a significant correlation with posterior Q value. CONCLUSION PE indices are sensitive detectors of early ectasia. PE from BFTE had the highest deduced AUROC. Alterations in PE values can significantly alter many posterior corneal aberrations and the posterior Q.
Collapse
|
49
|
Aslan MG, Fındık H, Okutucu M, Aydın E, Uzun F. The impact of hybrid contact lenses on keratoconus progression after accelerated transepithelial corneal cross-linking. Int Ophthalmol 2020; 41:45-55. [PMID: 32856196 DOI: 10.1007/s10792-020-01551-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/16/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate the effect of hybrid contact lenses (HCLs) on keratoconus (KCN) progression after accelerated transepithelial cross-linking (A-TE CXL). METHODS Thirty-five eyes of 26 patients who preferred Ultrahealth HCLs for an optical correction after A-TE CXL formed the study group, and 45 eyes of 34 patients who preferred spectacle correction were age- and sex-matched to form the control group. Corrected distance visual acuity (CDVA), maximum keratometry, mean keratometry, apical posterior keratometry, cylindrical power, minimum corneal thickness, keratoconus vertex indices and curvature asymmetry indices obtained by Scheimpflug corneal topography were compared before, 6 and 12 months after the procedure. Anterior segment optic coherence tomography (AS-OCT) was performed to measure the apical corneal clearance of HCL-wearing patients. RESULTS The median pre-CXL CDVA value of the patients in the HCL group was logMAR 0.30 (0.20-1.0), and it was logMAR 0.30 (0.10-1.0) in the spectacle-corrected group. There was a significant increase in CDVA 6 and 12 months after CXL procedure in both groups (p < 0.001, 0.003, respectively). The median front curve asymmetry index (FCAsym) significantly improved after A-TE CXL in the HCL group. The pre-CXL and 12th-month topographic comparisons of the spectacle-corrected group revealed no significant difference. In addition, no significant difference was observed between topographic alterations of two groups (p > 0.05). CONCLUSION The CDVA significantly improved, and KCN progression was halted in patients wearing HCL 12 months after A-TE CXL. Besides, FCAsym indices can be considered for follow-up of the HCL-wearing patients as an assistive parameter to AS-OCT measurements.
Collapse
Affiliation(s)
- Mehmet Gökhan Aslan
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Islampasa Mah, 53020, Merkez, Rize, Turkey.
| | - Hüseyin Fındık
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Islampasa Mah, 53020, Merkez, Rize, Turkey
| | - Murat Okutucu
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Islampasa Mah, 53020, Merkez, Rize, Turkey
| | - Emre Aydın
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Islampasa Mah, 53020, Merkez, Rize, Turkey
| | - Feyzahan Uzun
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Islampasa Mah, 53020, Merkez, Rize, Turkey
| |
Collapse
|
50
|
Tear Organic Acid Analysis After Corneal Collagen Crosslinking in Keratoconus. Eye Contact Lens 2020; 46 Suppl 2:S122-S128. [DOI: 10.1097/icl.0000000000000644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|