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Qureshi M, Watson SL, Kandel H. Pulsed corneal crosslinking in the treatment of Keratoconus: a systematic review and meta-analysis. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06622-7. [PMID: 39215849 DOI: 10.1007/s00417-024-06622-7] [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: 01/25/2024] [Revised: 07/29/2024] [Accepted: 08/15/2024] [Indexed: 09/04/2024] Open
Abstract
PURPOSE Corneal crosslinking (CXL) procedures are the treatment of choice in halting progressive corneal ectasia and preserving visual acuity due to keratoconus. Pulsed crosslinking (P-CXL) was developed using intermittent pulsing ultraviolet (UV) light to mitigate the depletion of oxygen levels that occurs with continuous UV exposure in standard crosslinking protocols (C-CXL). This study aimed to explore the use of P-CXL in the treatment of keratoconus and determine whether the availability of oxygen in P-CXL carries superior efficacy outcomes as an alternative to C-CXL modalities. METHODS This review was undertaken in accordance with PRISMA guidelines. A search of several databases conducted with two separate reviewers resulted in 29 papers meeting inclusion criteria for the review, 14 selected for meta-analysis. Primary outcomes assessed by the included papers included maximum keratometry (Kmax), corrected and uncorrected distance visual acuity (CDVA, UDVA), and secondary outcomes included central corneal thickness (CCT), endothelial cell count and demarcation line. Statistical analyses were carried out on Review Manager 5.4 and the meta-analysis employed a random-effects model, which estimated the weighted effect size of raw means using inverse variance weights. RESULTS At 12 months P-CXL showed statistically significant reductions in Kmax (-0.75 D; p < 0.001) and improvement in CDVA (-0.10 logMAR; p < 0.001) compared to baseline. The meta-analysis of comparative studies determined that mean differences in Kmax, CDVA, UDVA, Kmean and CCT after 12 months were not statistically significant between pulsed and continuous crosslinking groups. CONCLUSIONS Overall, P-CXL is effective in improving visual acuity and keratometry outcomes in keratoconus. The meta-analysis did not show a statistically significant difference in Kmax and CDVA between P-CXL and C-CXL, indicating a non-inferiority of P-CXL. However, findings of the meta-analysis are limited by the fact that different energy levels and exposure times were used for P-CXL in comparison to C-CXL in some studies, making it unsuitable to determine whether the efficacy of CXL is improved by the use of pulsed light. KEY MESSAGES What is Known • Pulsed crosslinking (P-CXL) uses intermittent UV light to prevent oxygen depletion when using higher energy protocols, unlike continuous UV exposure in standard continuous crosslinking (C-CXL). • This should theoretically enhance the efficacy of the treatment by maintaining higher oxygen levels that are crucial to the cross-linking process. • There are no systematic reviews or meta-analyses directly comparing the efficacy or safety of P-CXL to C-CXL. What is New • Meta-analysis revealed differences in keratometry between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (Kmax -0.04 dioptres; p = 0.84). • Meta-analysis revealed differences in visual acuity between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (CDVA -0.01 logMAR letters; p = 0.57). • The use of intermittent pulsing in higher energy CXL protocols renders statistically similar outcomes as continuous light exposure at equivalent fluence (7.2 J/cm2).
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Affiliation(s)
- Maria Qureshi
- Faculty of Medicine and Health, The University of Sydney, Save Sight Institute, Sydney, NSW, Australia
| | - Stephanie L Watson
- Faculty of Medicine and Health, The University of Sydney, Save Sight Institute, Sydney, NSW, Australia.
- Sydney Eye Hospital, the University of Sydney, Save Sight Institute, South Block, Level 1, 8 Macquarie Street, NSW, 2000, Sydney, Australia.
| | - Himal Kandel
- Faculty of Medicine and Health, The University of Sydney, Save Sight Institute, Sydney, NSW, Australia
- Sydney Eye Hospital, the University of Sydney, Save Sight Institute, South Block, Level 1, 8 Macquarie Street, NSW, 2000, Sydney, Australia
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Vaccaro S, Vivarelli C, Yu AC, Pecora N, Lionetti G, Gioia R, Scorcia V, Giannaccare G. Longitudinal Changes of Cornea Volume Measured by Means of Anterior Segment-Optical Coherence Tomography in Patients with Stable and Progressive Keratoconus. Life (Basel) 2024; 14:176. [PMID: 38398685 PMCID: PMC10890364 DOI: 10.3390/life14020176] [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: 12/10/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Keratoconus is a corneal disease which results in progressive thinning and protrusion of the cornea leading to irregular astigmatism. The purpose of this study was to evaluate longitudinal changes in corneal volume (CV) occurring over time in keratoconus eyes. Consecutive patients affected by keratoconus were evaluated by means of anterior segment-optical coherence tomography (AS-OCT) at two different time points: baseline (T0) and after 1 year (T1). Anterior and posterior refractive value; corneal thickness at the thinnest point (TP) and corneal volume (CV) calculated within discs of 3, 5 and 8 mm of diameter; anterior chamber depth (ACD); and anterior chamber volume (ACV) were obtained. Enrolled patients were divided into 3 groups (groups 1, 2, 3) according to the increasing disease severity and into 2 groups (groups A, B) according to the progression or stability of the disease. Overall, 116 eyes of 116 patients (76 males and 40 females, mean age 34.76 ± 13.99 years) were included. For the entire group of keratoconus patients, in comparison with T0, mean TP decreased at T1 from 458.7 ± 52.2 µm to 454.6 ± 51.6 µm (p = 0.0004); in parallel, mean value of CV calculated at 5 mm and 8 mm decreased significantly (from 10.78 ± 0.8 at T0 to 10.75 ± 0.79 at T1 (p = 0.02), and from 32.03 ± 2.01 mm3 at T0 to 31.95 ± 1.98 at T1 (p = 0.02), respectively). Conversely, there were no statistically significant differences in CV at 3 mm from T0 to T1 (p = 0.08), as well as for ACD and ACV. Regarding the course of the disease, patients belonging to group A showed statistically significant differences from T0 to T1 for TP, and for CV at 3 mm, 5 mm and 8 mm (p < 0.0001, p < 0.0001, p < 0.001 and p = 0.0058 respectively). There were no statistically significant differences for ACD (p = 0.6916) and ACV calculated at 3, 5 and 8 mm (p = 0.7709, p = 0.3765, p = 0.2475, respectively) in group A. At the same time, no statistically significant differences for ACD (p = 0.2897) and ACV calculated at 3, 5 and 8 mm (p = 0.9849, p = 0.6420, p = 0.8338, respectively) were found in group B. There were statistically significant positive correlations between changes of TP and CV at 3 mm (r = 0.6324, p < 0.0001), 5 mm (r = 0.7622, p < 0.0001) and 8 mm (r = 0.5987 p < 0.0001). In conclusion, given the strong correlation with TP, CV might be considered an additional AS-OCT parameter to be used in association with conventional parameters when detecting longitudinal changes in keratoconic eyes.
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Affiliation(s)
- Sabrina Vaccaro
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Chiara Vivarelli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.V.); (A.C.Y.)
- Department of Ophthalmology, Ospedali Privati Forlì “Villa Igea”, 47122 Forlì, Italy
| | - Angeli Christy Yu
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (C.V.); (A.C.Y.)
- Department of Ophthalmology, Ospedali Privati Forlì “Villa Igea”, 47122 Forlì, Italy
| | - Nicolò Pecora
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Giovanna Lionetti
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Raffaella Gioia
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Vincenzo Scorcia
- Department of Ophthalmology, University Magna Græcia of Catanzaro, 88100 Catanzaro, Italy; (S.V.); (N.P.); (G.L.); (R.G.); (V.S.)
| | - Giuseppe Giannaccare
- Eye Clinic, Department of Surgical Sciences, University of Cagliari, Via Università 40, 09124 Cagliari, Italy
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New Keratoconus Risk Factors: A Cross-Sectional Case—Control Study. J Ophthalmol 2022; 2022:6605771. [PMID: 36211596 PMCID: PMC9534614 DOI: 10.1155/2022/6605771] [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: 03/17/2022] [Revised: 07/26/2022] [Accepted: 08/25/2022] [Indexed: 11/20/2022] Open
Abstract
Purpose To evaluate risk factors associated with keratoconus in a monocentric cross-sectional case-control study. Methods This observational study occurred from June 2019 to February 2021 in a university hospital (France). The case group consisted of 195 patients with keratoconus in at least one eye who were followed up by a corneal specialist. The control group consisted of 195 patients without any evidence of keratoconus on slit-lamp examination and corneal topography, who were matched 1 : 1 to controls by age and sex. Data were collected by a self-completed paper questionnaire before the consultation, and a multivariate logistic regression was performed. Results Multivariate analysis revealed significant associations of keratoconus with family history (odds ratio [OR] = 22.2, p < 0.001), rubbing eyes (OR = 10.9, p < 0.001), allergy (any kind) (OR = 3.80, p < 0.001), smoking exposure (OR = 2.08, p=0.017), and dry eyes (OR = 1.77, p=0.045f). The worst eye was associated with the more rubbed eye (p < 0.001) and the more pressed eye during the night according to sleeping position (p < 0.041). Conclusion This study confirmed the association between keratoconus and eye rubbing, family history, and allergy. It highlighted the role of pressure on the eyes during sleep. Other less known risk factors such as dry eyes and smoking exposure should be explored in future studies.
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Hiraoka T, Kiuchi G, Hiraoka R, Oshika T. Clinical performance of a custom-designed soft contact lens in patients with keratoconus and intolerance to rigid contact lenses. Jpn J Ophthalmol 2022; 66:350-357. [PMID: 35670923 DOI: 10.1007/s10384-022-00924-1] [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: 09/05/2021] [Accepted: 04/05/2022] [Indexed: 11/26/2022]
Abstract
PURPOSE This study evaluated the efficacy and safety of YOUSOFT® soft contact lens (CL) (TOMEY-CL) in patients with keratoconus and intolerance to rigid CLs. STUDY DESIGN Retrospective observational study. METHODS Thirty-six eyes of 20 patients (14 men and 6 women) with keratoconus and rigid CL intolerance were included in the study. Four patients were unilateral. The mean age was 33.1 ± 11.7 (± standard deviation) years, the mean spherical refractive error was - 4.99 ± 3.97 D, and the mean cylindrical refractive error was - 3.39 ± 2.13 D. The following examinations were performed at baseline and were repeated at every visit; refractometry, visual acuity, corneal topography and pachymetry with an anterior OCT system. Corneal endothelial cell density was evaluated at baseline and every 6 months. Slit-lamp examination was also performed to confirm the CL condition and ocular health at every visit. RESULTS Seventeen patients (85%) were able to continue using the Yousoft. Among 3 patients (15%) who dropped out, 2 were dissatisfied with their visual outcomes and one had trouble with lens handling. Uncorrected visual acuity was 1.08 ± 0.43 (range: 0.22 to 2.00) logMAR at baseline, and best CL-corrected visual acuity was 0.01 ± 0.15 (range: - 0.18 to 0.40) logMAR, showing a significant improvement after wearing Yousoft (P < 0.0001). The endothelial cell density did not change significantly, with 2373 ± 482 at baseline and 2402 ± 464 cells/mm2 at the latest visit after lens prescription (P = 0.351). There were no severe complications such as corneal infiltrates or infectious keratitis throughout the study period. CONCLUSIONS This study showed the efficacy and acceptable safety of Yousoft for patients with keratoconus and intolerance to rigid CLs.
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Affiliation(s)
- Takahiro Hiraoka
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
| | - Gaku Kiuchi
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Reia Hiraoka
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Tetsuro Oshika
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan
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Williams KA, Keane MC. Outcomes of corneal transplantation in
Australia
, in an era of lamellar keratoplasty. Clin Exp Ophthalmol 2022; 50:374-385. [DOI: 10.1111/ceo.14089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Keryn A. Williams
- Department of Ophthalmology, Flinders Health and Medical Research Institute, College of Medicine and Public Health Flinders University Adelaide Australia
| | - Miriam C. Keane
- Department of Ophthalmology, Flinders Health and Medical Research Institute, College of Medicine and Public Health Flinders University Adelaide Australia
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Maile H, Li JPO, Gore D, Leucci M, Mulholland P, Hau S, Szabo A, Moghul I, Balaskas K, Fujinami K, Hysi P, Davidson A, Liskova P, Hardcastle A, Tuft S, Pontikos N. Machine Learning Algorithms to Detect Subclinical Keratoconus: Systematic Review. JMIR Med Inform 2021; 9:e27363. [PMID: 34898463 PMCID: PMC8713097 DOI: 10.2196/27363] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/10/2021] [Accepted: 10/14/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Keratoconus is a disorder characterized by progressive thinning and distortion of the cornea. If detected at an early stage, corneal collagen cross-linking can prevent disease progression and further visual loss. Although advanced forms are easily detected, reliable identification of subclinical disease can be problematic. Several different machine learning algorithms have been used to improve the detection of subclinical keratoconus based on the analysis of multiple types of clinical measures, such as corneal imaging, aberrometry, or biomechanical measurements. OBJECTIVE The aim of this study is to survey and critically evaluate the literature on the algorithmic detection of subclinical keratoconus and equivalent definitions. METHODS For this systematic review, we performed a structured search of the following databases: MEDLINE, Embase, and Web of Science and Cochrane Library from January 1, 2010, to October 31, 2020. We included all full-text studies that have used algorithms for the detection of subclinical keratoconus and excluded studies that did not perform validation. This systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations. RESULTS We compared the measured parameters and the design of the machine learning algorithms reported in 26 papers that met the inclusion criteria. All salient information required for detailed comparison, including diagnostic criteria, demographic data, sample size, acquisition system, validation details, parameter inputs, machine learning algorithm, and key results are reported in this study. CONCLUSIONS Machine learning has the potential to improve the detection of subclinical keratoconus or early keratoconus in routine ophthalmic practice. Currently, there is no consensus regarding the corneal parameters that should be included for assessment and the optimal design for the machine learning algorithm. We have identified avenues for further research to improve early detection and stratification of patients for early treatment to prevent disease progression.
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Affiliation(s)
- Howard Maile
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | | | - Daniel Gore
- Moorfields Eye Hospital, London, United Kingdom
| | | | - Padraig Mulholland
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom.,Centre for Optometry & Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
| | - Scott Hau
- Moorfields Eye Hospital, London, United Kingdom
| | - Anita Szabo
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | | | | | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Pirro Hysi
- Section of Ophthalmology, School of Life Course Sciences, King's College London, London, United Kingdom.,Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Alice Davidson
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Alison Hardcastle
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Stephen Tuft
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
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Richter K, Jullien T, Klühspies U, Langenbucher A, Seitz B, Eppig T. Contact Lens Fitting in Patients with Keratoconus - A Retrospective Assessment of 200 Patients. Klin Monbl Augenheilkd 2021; 239:1155-1163. [PMID: 34731900 DOI: 10.1055/a-1526-9861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND PURPOSE Nowadays, keratoconus (KC) is very well treatable in a stage-oriented manner. A wide range of designs and materials of contact lenses (CL) are available for the treatment of KC. The aim of this study was to evaluate the possibilities, the possible challenges and the visual outcome of lens fitting in KC eyes. PATIENTS AND METHODS This retrospective study includes data from 200 patients who received a lens fitting trial in our contact lens service between 2006 and 2016. We documented ophthalmological parameters, the type of prescribed CL, the number of required trial lenses and possible causes of the failure of the lens fitting. RESULTS The mean age at initial lens fitting was 33.9 ± 12.5 years. In 98.8% of the cases, the fitting was performed with rigid gas permeable lenses, in 90.1% with four-curve lenses. Of the total number of aspheric lenses prescribed, 87.5% were fitted in keratoconus stages "1" to "2" (topographic keratoconus classification; Oculus Keratograph). Back surface toric lenses or bitoric lenses were fitted to 61.7% in keratoconus stages "2 - 3" to "4". Before patients received their final CL, a median of 2 trial lenses were required (max. 16). Mean visual acuity with lens correction was 0.8 ± 0.2 at the initial fitting, mean visual acuity with glasses correction was 0.5 ± 0.3. In 7.7% of the eyes, the KC lens fitting was discontinued due to the advanced stage of keratoconus, requiring a corneal transplant. Reasons for discontinuing contact lens fitting included lens intolerance (2.3%), application problems (0.3%) or acute corneal hydrops (0.3%). Discontinuation of lens wearing due to incompatibilities or application problems occurred in only four cases (1.1%) in the further course after lens fitting. CONCLUSIONS The use of contact lenses is an integral part of the stage-appropriate therapy of keratoconus. Good visual acuity can be achieved in all stages of keratoconus with a low drop-out rate. In most cases, the adjustment is carried out with rigid gas permeable lenses with a four-curve geometry. In initial stages, aspherical lenses may be sufficient. Toric lenses can be fitted in advanced stages when rotationally symmetrical lenses cannot achieve a satisfactory fit. If contact lenses have been successfully fitted, there are only a few cases in which patients abandon their contact lenses because of intolerance.
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Affiliation(s)
- Kathrin Richter
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg/Saar
| | - Theresia Jullien
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg/Saar
| | - Ulrike Klühspies
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg/Saar
| | - Achim Langenbucher
- Institut für Experimentelle Ophthalmologie, Universität des Saarlandes, Homburg/Saar
| | - Berthold Seitz
- Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg/Saar
| | - Timo Eppig
- Institut für Experimentelle Ophthalmologie, Universität des Saarlandes, Homburg/Saar
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Baird PN, Machin H, Brown KD. Corneal supply and the use of technology to reduce its demand: A review. Clin Exp Ophthalmol 2021; 49:1078-1090. [PMID: 34310836 DOI: 10.1111/ceo.13978] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 11/26/2022]
Abstract
Recovery and access to end-of-life corneal tissue for corneal transplantation, training and research is globally maldistributed. The reasons for the maldistribution are complex and multifaceted, and not well defined or understood. Currently there are few solutions available to effectively address these issues. This review provides an overview of the system, key issues impacting recovery and allocation and emphasises how end-user ophthalmologists and researchers, with support from administrators and the wider sector, can assist in increasing access long-term through sustaining eye banks nationally and globally. We posit that prevention measures and improved surgical techniques, together with the development of novel therapies will play a significant role in reducing demand and enhance the equitable allocation of corneas.
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Affiliation(s)
- Paul N Baird
- Department of Surgery, Ophthalmology, University of Melbourne, Melbourne, Victoria, Australia
| | - Heather Machin
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- Lions Eye Donation Service, Melbourne, Australia
| | - Karl D Brown
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
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Brar S, Ganesh S, Reddy SS, Bn N, Shahanand D. A Prospective, Comparative, Clinical Study to Evaluate the Safety and Efficacy of Two Different 0.1% Riboflavin Solutions Used in Collagen Crosslinking Treatment for Patients with Keratoconus. Clin Ophthalmol 2021; 15:2607-2617. [PMID: 34188439 PMCID: PMC8232965 DOI: 10.2147/opth.s313647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 05/28/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose To compare the safety and efficacy of 0.1% riboflavin in two different solutions which is used in corneal collagen crosslinking (CXL) for the treatment of keratoconus. Methods This was a prospective, randomized, comparison study which included 100 eyes of 61 patients with progressive keratoconus who underwent CXL with riboflavin 0.1% solution as a photosensitizer, using the standard Dresden protocol of using 3mW/cm2 UV-A irradiation for 30 minutes which corresponds to a total energy of 5.4 J/cm2. The recruited patients were divided into 2 groups ie, Flavin Group and Peschke-D group by computer generated randomization. Postoperative examinations were conducted on 1 day, 1 month, 3 months, 6 months and 12 months after the crosslinking. Results For both groups, the mean manifest spherical equivalent (SE), astigmatism, best corrected distance visual acuity, keratometry values, thinnest pachymetry values, demarcation line depth and endothelial cell density preoperatively and at postoperative 12 months were comparable with no statistically significant differences. At 12 months postoperatively, 62% of eyes in the Flavin group, and 68% of eyes in the Peschke-D group had postoperative manifest SE of within ± 1.00 D. During UV-A exposure, the cornea in the Flavin group showed intraoperative thinning of 112 microns (27%) as compared with a thinning of 108.12 microns (26.5%) observed in the Peschke group (p=1.67) from the initial pachymetry readings. No eye in either group had any immediate or long-term postop vision threatening complications such as infectious keratitis, corneal melt, non-resolving corneal oedema or endothelial decompensation. Conclusion Both riboflavin solutions were equally safe and effective in the management of progressive keratoconus, and resulted in similar changes in terms of mean manifest spherical equivalent (SE), astigmatism, best corrected distance visual acuity, keratometry values, thinnest pachymetry values, demarcation line depth and endothelial cell density at the end of 12 months postoperatively. Trial Registration Number Ctri/2019/11/021841 (Www.ctri.nic.in).
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Affiliation(s)
- Sheetal Brar
- Department of Phaco-Refractive Surgery, Nethradhama Superspecialty Eye Hospital, Bangalore, Karnataka, India
| | - Sri Ganesh
- Department of Phaco-Refractive Surgery, Nethradhama Superspecialty Eye Hospital, Bangalore, Karnataka, India
| | - Shilpa S Reddy
- Department of Phaco-Refractive Surgery, Nethradhama Superspecialty Eye Hospital, Bangalore, Karnataka, India
| | - Nagesh Bn
- Department of Phaco-Refractive Surgery, Nethradhama Superspecialty Eye Hospital, Bangalore, Karnataka, India
| | - Dhwni Shahanand
- Department of Phaco-Refractive Surgery, Nethradhama Superspecialty Eye Hospital, Bangalore, Karnataka, India
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10
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Andreev AY, Osidak EO, Grigoriev TE, Krasheninnikov SV, Zaharov VD, Zaraitianc OV, Borzenok SA, Domogatsky SP. A new collagen scaffold for the improvement of corneal biomechanical properties in a rabbit model. Exp Eye Res 2021; 207:108580. [PMID: 33872673 DOI: 10.1016/j.exer.2021.108580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/18/2021] [Accepted: 04/10/2021] [Indexed: 10/21/2022]
Abstract
Although collagen based materials are widely used in corneal tissue engineering with promising results. The usage of such materials for the improvement of corneal biomechanical properties is still unclear. In this study, we aimed to investigate a new Viscoll collagen-based membrane for the improvement of corneal biomechanical characteristics.The right eyes of 15 Chinchilla rabbits were implanted with the membrane via an intrastromal pocket, with the contralateral intact eyes as controls. At 7, 30, 90, and 180 days post-surgery, the rabbits underwent anterior segment optical coherence topography, clinical examination, and slit-lamp microscopy. Additionally, the corneal samples also underwent histological examination followed by the assessment of the biomechanical characteristics of four treated and non-treated corneas at 30, 90, and 180 days, including keratometry at 180 days, post operation. Data are presented as means ± confidence intervals with a 95% confidence level. All the operated corneas retained their transparency throughout the study. Implantation approximately doubled the central corneal thickness. Corneas became stronger by approximately 87% between 1 and 6 months after surgery (maximum fracture load, 13.3 ± 0.8 and 24.9 ± 1.4 N, respectively), and their elasticity increased by approximately 27% over the same time frame (maximum slope of the elastic region of the stress-strain curve, 11.5 ± 0.2 and 14.6 ± 1.4 N/mm respectively). We have thus proposed a new method to increase corneal thickness and strengthen the corneal tissues while preserving their transparency and demonstrated its safety and efficacy in a rabbit model over 6 months. This may be a suitable alternative to the existing corneal collagen crosslinking procedure.
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Affiliation(s)
- Andrey Yurevich Andreev
- LEС Ltd., Rozhdestvenskaya, 7, Mytischi, Russia; Imtek Ltd., 3rd Cherepkovskaya 15A, Moscow, Russia; Research Institute of Eye Diseases, 11A Rossolimo St., Moscow, Russia
| | - Egor Olegovich Osidak
- Imtek Ltd., 3rd Cherepkovskaya 15A, Moscow, Russia; Gamaleya Research Institute of Epidemiology and Microbiology, FSBI MOH Russia, Gamalei 18, Moscow, Russia.
| | | | | | | | | | | | - Sergey Petrovich Domogatsky
- Imtek Ltd., 3rd Cherepkovskaya 15A, Moscow, Russia; Russian Cardiology Research and Production Center, Federal State Budgetary Institution, Ministry of Health of the Russian Federation, 3 Cherepkovskaya 15A, Moscow, Russia
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11
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Hodge C, Chan C, Zantos S, Kokkinakis J, Stapleton F, Sutton G. Therapeutic treatment of keratoconus: a survey of local optometric practice criteria. Clin Exp Optom 2021; 98:312-8. [DOI: 10.1111/cxo.12233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/03/2014] [Accepted: 09/30/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
| | - Colin Chan
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | | | - Jim Kokkinakis
- School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
- The Eye Practice, , Sydney, NSW, Australia
| | - Fiona Stapleton
- School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Gerard Sutton
- Vision Eye Institute Chatswood, NSW, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Save Sight Institute, University of Sydney, Sydney, NSW, Australia
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12
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AlQahtani BS, Alshahrani S, Khayyat WW, Abdalla-Elsayed MEA, Altalhi AA, Saifaldein AA, Taha MA. Outcomes of Corneal Topography among Progressive Keratoconus Patients 12 months following Corneal Collagen Cross-Linking. Clin Ophthalmol 2021; 15:49-55. [PMID: 33442228 PMCID: PMC7800689 DOI: 10.2147/opth.s284981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/04/2020] [Indexed: 12/03/2022] Open
Abstract
Purpose This study aimed to assess the overall and specific topographic changes among patients who underwent corneal collagen cross-linking (CXL) due to progressive keratoconus. Methods This retrospective case series study was conducted at a single-arm hospital in King Abdulaziz Medical City, Riyadh. All progressive keratoconus patients who underwent CXL between January 2017 and December 2018 were included consecutively. The epi-off crosslinking technique (Dresden protocol) was applied in all patients. The topographic values were measured preoperatively and 12 months postoperatively. Patients with a history of a previous corneal procedure, corneal trauma, or any corneal scarring were excluded. Results Among our population (29 eyes of 24 patients), 58.6% of eyes were for male patients, and the mean age of the population was 27.76 ± 4.21 years. Based on the topography results, the mean values of corneal thickness at central 3 mm decreased from 473.45 ± 38 µm to 465.72 ± 41.78 µm following CXL (Z = −1.93, 95% confidence interval [CI] = 0.048–0.057, p= 0.053). Clinically significant astigmatism measurements were present in 28 (96.6%) eyes before CXL compared to 26 (89.7%) eyes after CXL. The mean values of astigmatism among the patients were 3.37 ± 2.25 diopters before and 3.67 ± 2.61 diopters after CXL (Z = −1696, 95% confidence interval [CI] = 0.085–0.096, p = 0.09). After CXL, the mean values of the front elevation at the apex changed from 33.90 ± 20.13 µm to 36.10 ± 21.09 µm (Z = −2.792, 95% [CI] = 0.003–0.006, p = 0.005). The mean values of the back elevation at the apex changed from 68.4 ± 35.66 µm to 69.90 ± 35.89 µm (Z = −0.934, 95% CI = 0.343–0.366, p = 0.35). Conclusion The topographic corneal parameters improved significantly in the patients with corneal ectasia after CXL. These results revealed the safety and efficacy of CXL in stabilizing keratoconus progression among Saudi patients at 1 year of follow-up.
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Affiliation(s)
- Bader S AlQahtani
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia.,Department of Ophthalmology, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia
| | - Saeed Alshahrani
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Waleed W Khayyat
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia.,King Khalid Eye Specialist Hospital, Riyadh, Saudi Arabia
| | | | - Abdullah A Altalhi
- Department of Ophthalmology, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia.,College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Amjad A Saifaldein
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed A Taha
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
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13
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Gore DM, Leucci MT, Koay SY, Kopsachilis N, Nicolae MN, Malandrakis MI, Anand V, Allan BD. Accelerated Pulsed High-Fluence Corneal Cross-Linking for Progressive Keratoconus. Am J Ophthalmol 2021; 221:9-16. [PMID: 32818448 DOI: 10.1016/j.ajo.2020.08.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/09/2020] [Accepted: 08/09/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE To report on 2-year results of accelerated corneal collagen cross-linking (CXL) in progressive ectasia using the Avedro KXL system. DESIGN Prospective interventional case series. METHODS A total of 870 patients (1,192 eyes) attending Moorfields Eye Hospital after CXL were included. All patients undergoing CXL had progressive keratoconus. Corneas with a minimum stromal thickness <375 μm were excluded. Riboflavin 0.1% soak duration was 10 minutes. High-fluence pulsed UVA was delivered at 30 mW/cm2 for 4 minutes, with a 1.5-second on/off cycle (total energy 7.2 J/cm2). Subjective refractive, corneal tomography, and specular microscopy were performed at baseline, 6, 12, and 24 months postoperatively. The primary outcome measure was a change in maximum keratometry (Kmax) at 24 months. RESULTS Twelve- and 24-month follow-up data were available on 543 and 213 patients, respectively (mean age 25.4 ± 6.6 years). In mild cones (Kmax < 55 diopter [D]), mean keratometry remained unchanged at 24 months. In more advanced disease, we observed modest corneal flattening compared to baseline (Kmax 63.2 ± 6.5 D vs 61.9 ± 8.1 D, P = .02), but no significant changes in central keratometry (K1 or K2). Keratometric stabilization was confirmed in 98.3% of eyes. Mean CDVA, manifest refraction and endothelial cell density did not change. Overall, 2.7% of eyes lost more than 2 lines of CDVA. CONCLUSION Accelerated pulsed CXL is a safe, effective, and refractively neutral intervention (at 2 years) to halt disease progression in keratoconus.
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Affiliation(s)
- Daniel M Gore
- External Disease Service, Moorfields Eye Hospital, London, United Kingdom.
| | - Marcello T Leucci
- External Disease Service, Moorfields Eye Hospital, London, United Kingdom; Keratoconus Monitoring Service, Moorfields Eye Hospital, London, United Kingdom
| | - Su-Yin Koay
- External Disease Service, Moorfields Eye Hospital, London, United Kingdom
| | | | - Michael N Nicolae
- External Disease Service, Moorfields Eye Hospital, London, United Kingdom
| | | | - Vijay Anand
- External Disease Service, Moorfields Eye Hospital, London, United Kingdom; Keratoconus Monitoring Service, Moorfields Eye Hospital, London, United Kingdom
| | - Bruce D Allan
- External Disease Service, Moorfields Eye Hospital, London, United Kingdom
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14
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Tunç U, Akbaş YB, Yıldırım Y, Kepez Yıldız B, Kırgız A, Demirok A. Repeatability and reliability of measurements obtained by the combined Scheimpflug and Placido-disk tomography in different stages of keratoconus. Eye (Lond) 2020; 35:2213-2220. [PMID: 33106613 DOI: 10.1038/s41433-020-01238-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 09/18/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE The objective of this study is to evaluate the repeatability and reliability of corneal parameters in different stages of keratoconus patients using a combined Scheimpflug-Placido disc analysis system. MATERIALS AND METHODS In this prospective study, three consecutive measurements were performed by the same observer using Scheimpflug-Placido disc anterior segment analysis device in keratoconus patients. Flattest and steepest simulated keratometry and corneal volume, corneal aberrations, thinnest corneal thickness, symmetry index, keratoconus vertex and Baiocchi-Calossi-Versaci index were recorded. Keratoconic eyes were divided into four stages using the Amsler-Krumeich classification. Repeatability was evaluated using within the subject standard deviation, repeatability index (Ri) and coefficient of variation; reliability was evaluated by intraclass correlation coefficient (ICC). Pearson correlation coefficients were used to assess the correlation between the parameters evaluated. RESULTS Two hundred sixty-one eyes of 261 keratoconus patients were included in the study. The repeatability for all corneal curvature parameters decreased as the keratoconus severity increased, and there is a positive correlation between keratometry of the apex and corneal curvature parameters (p < 0.05) except mean simulated keratometry. The corneal aberrations were repeatable in all keratoconus subgroups (Ri < 0.34 μm). There are also positive correlations between keratometry of apex and corneal aberrations (p < 0.05) except total high-order root mean square and spherical aberration. The reliability was excellent (ICC > 0.90) for all indices except keratoconus vertex back. CONCLUSION The parameters used in the diagnosis and follow-up of keratoconus in the Sirius corneal tomography system may differ more than expected at stages 3 and 4 of the disease. Awareness of this situation may be helpful in planning follow-up and treatment.
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Affiliation(s)
- Uğur Tunç
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Yusuf Berk Akbaş
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Yusuf Yıldırım
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey.
| | - Burçin Kepez Yıldız
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Kırgız
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Demirok
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
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15
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Histological Corneal Alterations in Keratoconus After Crosslinking—Expansion of Findings. Cornea 2019; 39:333-341. [DOI: 10.1097/ico.0000000000002144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Quartilho A, Gore DM, Bunce C, Tuft SJ. Royston-Parmar flexible parametric survival model to predict the probability of keratoconus progression to corneal transplantation. Eye (Lond) 2019; 34:657-662. [PMID: 31462761 DOI: 10.1038/s41433-019-0554-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 05/11/2019] [Accepted: 07/04/2019] [Indexed: 01/03/2023] Open
Abstract
PURPOSE To assess a Royston-Parmar flexible parametric survival model to generate a personalised risk profile for keratoconus progression. METHODS We re-analysed a historic database of 2723 individuals with keratoconus. A Royston-Parmar survival model was fitted to predict the likelihood of the worse eye progressing to corneal transplantation. We used a backwards selection multivariable fractional polynomial procedure to assist with selection of covariates and identify appropriate transformation(s) to retain in the final model. Time-dependent receiver operating characteristic (ROC) curves from censored survival data using the Kaplan-Meier (KM) method were computed to visually assess how well the model identified eyes likely to progress. RESULTS In all, 5020 eyes from 2581 patients were available for model development. This included 2378 worst affected eyes, and 313 eyes that progressed to transplantation. The best fitting model [df = 1: Bayes information criterion (BIC) = 1573] included three variables, keratometry [hazard ratio (HR) 0.36: 95% confidence limits (CI) 0.32-0.42], age at baseline [HR 0.97: CI 0.95-0.99] and ethnicity [HR 3.92: CI 2.58-5.95]. Specificity at 1 year was 92.8% (CI 90.4-95.2%) with a corresponding sensitivity of 64.6% (CI 58.9-60.0%). These three prognostic factors account for 41.3% (CI 33.6 - 48.2%) of the variation among the survival curves. CONCLUSION Researchers should consider the Royston-Parmar model as an alternative to the Cox model. We illustrate the concepts and our results may lead to better tools that identify individuals at high risk of keratoconus progression.
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Affiliation(s)
- Ana Quartilho
- Research & Development, NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, London, UK.,Comprehensive Clinical Trials Unit, University College London, 90 High Holborn, London, UK
| | - Daniel M Gore
- External Disease Department, Moorfields Eye Hospital, 162 City Road, London, UK
| | - Catey Bunce
- Research & Development, NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, London, UK.,Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK.,Primary Care & Public Health Sciences, King's College London, Addison House, Guy's Hospital, London, UK
| | - Stephen J Tuft
- External Disease Department, Moorfields Eye Hospital, 162 City Road, London, UK.
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17
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Combined Phototherapeutic Keratectomy, Intracorneal Ring Segment Implantation, and Corneal Collagen Cross-Linking in Keratoconus Management. Cornea 2019; 38:1233-1238. [DOI: 10.1097/ico.0000000000002073] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Koh IH, Seo KY, Park SB, Yang H, Kim I, Kim JS, Hwang DG, Nam SM. One-Year Efficacy and Safety of Combined Photorefractive Keratectomy and Accelerated Corneal Collagen Cross-Linking after Intacs SK Intracorneal Ring Segment Implantation in Moderate Keratoconus. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7850216. [PMID: 31360724 PMCID: PMC6644267 DOI: 10.1155/2019/7850216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 06/24/2019] [Indexed: 11/17/2022]
Abstract
PURPOSE To report one-year outcomes of a modified version of two-stage multimodal surgical protocol for moderate keratoconus which has been suggesting promising preliminary results. MATERIALS AND METHODS 30 eyes of 25 patients with moderate keratoconus who exhibited visual complaints and/or disease progression were included for this retrospective case study. Approximately 3 months after implantation of intracorneal ring segment (Intacs SK™), a combination of corneal wavefront-guided transepithelial photorefractive keratectomy (CWG-transPRK, Schwind Amaris® 1050, and Schwind Sirius) and accelerated collagen cross-linking (accCXL, Avedro KXL™) was performed. Patients were examined for uncorrected and corrected distance visual acuity (UDVA; CDVA), keratometric power (K), corneal thickness, and corneal higher-order aberrations (HOAs) preoperatively and at postoperative 1, 3, 6, and 12 months. RESULTS The median UDVA and mean CDVA were enhanced from 6/38 to 6/12 and from 6/19 to 6/7.5, respectively, through 12 months after CWG-transPRK/accCXL. The 12-month CDVA of all patients was better than 6/12 Snellen, and no subject lost one or more lines of CDVA. The magnitudes of both myopia and corneal steepness were decreased in turn by Intacs SK implantation and also by CWG-transPRK/accCXL, but the reduction in HOA was largely the result of CWG-transPRK/accCXL. The magnitude of corneal thinning stabilized within 3 months after CWG-transPRK/accCXL. CONCLUSION This approach may allow patients with moderate keratoconus to obtain satisfactory vision without the need for contact lens wear. This surgery appeared to be effective and safe through 1 year of follow-up.
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Affiliation(s)
- Il Hwan Koh
- SU Yonsei Eye Clinic, Seoul, Republic of Korea
| | - Kyoung Yul Seo
- Department of Ophthalmology, Institute of Vision Research, Eye and Ear Hospital, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | | | - Hun Yang
- SU Yonsei Eye Clinic, Seoul, Republic of Korea
| | - InSik Kim
- SU Yonsei Eye Clinic, Seoul, Republic of Korea
| | - Jin Sun Kim
- SU Yonsei Eye Clinic, Seoul, Republic of Korea
| | - David G. Hwang
- Cornea Service and Refractive Surgery Service, Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Sang Min Nam
- Department of Ophthalmology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea
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19
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Effect of Keratoconus Severity on Clinical Outcomes After Deep Anterior Lamellar Keratoplasty. Am J Ophthalmol 2019; 202:15-22. [PMID: 30731083 DOI: 10.1016/j.ajo.2019.01.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/02/2018] [Accepted: 01/24/2019] [Indexed: 11/21/2022]
Abstract
PURPOSE To evaluate the effect of keratoconus severity on the visual and refractive outcomes and complications after deep anterior lamellar keratoplasty (DALK). DESIGN Consecutive interventional case series. METHODS This study enrolled 227 keratoconus-affected eyes that underwent DALK. Amsler-Krumeich keratoconus classification was used to categorize the patients: stage II, 47 eyes; stage III, 60 eyes; and stage IV, 120 eyes. The outcome measures, including postoperative best spectacle-corrected visual acuity (BSCVA), spherical equivalent refraction, mean keratometry, keratometric astigmatism, and complications, were analyzed and compared based on keratoconus stage. RESULTS The mean patient age was 27.6 ± 8.0 years, and the mean follow-up period was 38.0 ± 19.8 months. No significant differences were observed in postoperative BSCVA (P = .55), spherical equivalent refraction (P = .27), mean keratometry (P = .09), and keratometric astigmatism (P = .14) among the groups. Improvement in BSCVA were significantly greater in stage III and stage IV compared with stage II (P = .04 and P < .001, respectively). The decrease in spherical equivalent was significantly greater in stages III and IV compared with stage II (P = .04 and P = .001, respectively). Mean keratometry decreased to a greater degree in stage IV compared with stages II and III (P < .001 for both comparisons). The study groups were comparable with respect to intraoperative Descemet membrane perforation, the rate of successful big-bubble formation, suture-related complications, and graft rejection. CONCLUSIONS DALK is a safe and effective procedure for the treatment of all stages of keratoconus. This technique of corneal transplantation is more effective in eyes with severe keratoconus compared with those with moderate keratoconus.
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20
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Kanellopoulos AJ. The impact of keratoconus treatment with the Athens Protocol (partial topography-guided photorefractive keratectomy combined with higher-fluence corneal collagen cross-linking) on quality of life: a long-term study. Clin Ophthalmol 2019; 13:795-803. [PMID: 31118557 PMCID: PMC6501993 DOI: 10.2147/opth.s188519] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose The aim of this study was to evaluate the health-related quality of life (HRQoL) before and after the management of keratoconus (KCN) with Combined Topography-Guided Transepithelial partial photorefractive keratectomy (PRK) and corneal Cross-Linking: the Athens Protocol. Patients and methods Thirty-four consecutive patients treated for progressive KCN were selected for retrospective telephone interview and individual questionnaire submission. A disease-specific HRQoL questionnaire was administered before and after the Athens Protocol intervention, using the following administrative questionnaires: National Eye Institute Visual Function Questionnaire (NEI VFQ) 25/39 and IVI-28. The disease grade was ranked according to the Amsler–Krumeich classification (KCN severity). Reliability of collected data was evaluated with Cronbach’s α test. Results Patients’ age ranged from 15 to 51 years at the time of the operation. Mean time before the operation during which the questionnaires were administered was 52±6 months. General visual acuity, psychological well-being, and driving ability showed significant improvement. Younger keratoconic patients tend to have more enhanced psychological status and to cope better with difficulties in everyday activities (prior to operation) than older patients. Conclusion The Athens Protocol treatment has been proven to be beneficial to patients in a large number of aspects.
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Affiliation(s)
- Anastasios John Kanellopoulos
- Department of Ophthalmology, Laservision.gr, Clinical and Research Eye Institute, Athens, Greece, .,NYU Medical School, Department of Ophthalmology, New York, NY, USA,
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21
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Sitnik GV, Slonimskiy AY, Slonimskiy YB, Imshenetskaya TA. [Femtolaser-assisted refractive autokeratoplasty in the management of advanced keratoconus (three-years outcomes)]. Vestn Oftalmol 2019; 135:28-35. [PMID: 30830071 DOI: 10.17116/oftalma201913501128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate the long-term results of a new method of femtosecond laser-assisted refractive autokeratoplasty (FRAK) in the management of advanced keratoconus. MATERIAL AND METHODS The study included 45 patients with stable advanced keratoconus (31 males, 14 females; stage III of the disease - 5 eyes, stage IV - 40 eyes). All patients were operated and observed at the 10th Minsk City Hospital (the follow-up period varied from 12 months to 3 years). Mean age was 33.8±10.1 years (16 to 55 years). Uncorrected visual acuity (UCVA) was 0.07±0.03 (0.02 to 0.1). FRAK was performed with the use of the femtolaser device 'IntraLase 60 kHz'. The principal idea behind the new method is reshaping patient's conically changed cornea by performing a 2-step resection of corneal stroma, removing the tissue flap and suturing. RESULTS UCVA significantly improved from 0.07±0.03 to 0.26±0.11 at 12 months after the surgery (from 0.08 to 0.5). UCVA varied from 0.2 to 0.5 in 77.8% of patients (p<0.05). Mean best corrected visual acuity (BCVA) was 0.4±0.18 (0.2 to 0.7) in 24-36 months postoperatively. The indices of keratotopography significantly improved: Ks 49.8±4.7 D, Kf 44.2±5.19 D, Cyl 4.8±1.9 D, Kmax 53.7±3.9 D (p<0.05). 82.2% of patients were satisfied with resulting visual acuity. CONCLUSION Long term results of FRAK prove that this method allows reshaping of optical zone of the cornea in advanced keratoconus, improving both UCVA and BCVA while avoiding corneal transplantation and improving the quality of patient's life.
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Affiliation(s)
- G V Sitnik
- Belarusian Medical Academy of Postgraduate Education, Department of Ophthalmology, 3-3 Petrusya Brovki St., Minsk, Republic of Belarus, 220013
| | - A Y Slonimskiy
- Moscow Eye Clinic LLC, 11 Semyonovskiy ln., Moscow, Russian Federation, 107023
| | - Y B Slonimskiy
- Russian Medical Academy of Continuous Professional Education, Department of Ophthalmology, 2/1 Barricadnaya St., Moscow, Russian Federation, 125993
| | - T A Imshenetskaya
- Belarusian Medical Academy of Postgraduate Education, Department of Ophthalmology, 3-3 Petrusya Brovki St., Minsk, Republic of Belarus, 220013
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22
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O'Brart NAL, O'Brart DPS, Aldahlawi NH, Hayes S, Meek KM. An Investigation of the Effects of Riboflavin Concentration on the Efficacy of Corneal Cross-Linking Using an Enzymatic Resistance Model in Porcine Corneas. Invest Ophthalmol Vis Sci 2018; 59:1058-1065. [PMID: 29490342 PMCID: PMC6436846 DOI: 10.1167/iovs.17-22994] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To investigate riboflavin concentration on enzymatic resistance following corneal cross-linking (CXL). Methods Ninety-six porcine eyes were divided into five groups in two treatment runs. Group 1 remained untreated. Group 2 received riboflavin 0.05%, group 3 riboflavin 0.1%, group 4 riboflavin 0.2%, and group 5 riboflavin 0.3%. Treated eyes underwent CXL with ultraviolet A at 9 mW/cm2 for 10 minutes. Eight-millimeter discs from each cornea were submerged in pepsin digest solution. In the first run, disc diameters were measured daily. After 10 days, dry weights were recorded from five samples in each group. In the second run, dry weights were recorded in five samples in each group at 10 and 20 days. Results CXL-treated corneas took longer to digest than untreated (P < 0.001). Although eyes treated with higher riboflavin concentrations generally took longer to digest, there were no significant differences between groups (P = 0.3). Dry weights at 10 days demonstrated, with each increase in concentration, an increase in weight of residual undigested tissue (P < 0.001). In the second run, with each increase in riboflavin concentration there was an increase in weight of residual tissue (P < 0.001) at 10 days. At 20 days, the dry weight was lower with 0.05% riboflavin compared to 0.3% (P < 0.001) and 0.2% and 0.1% solutions (P < 0.05), with no other difference between groups. Conclusions There is a consistent dose-response curve with higher concentrations of riboflavin achieving greater CXL efficacy, suggesting that manipulation of riboflavin dosage as well as the UVA protocol can be used to optimize CXL.
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Affiliation(s)
| | - David P S O'Brart
- Keratoconus Research Institute, Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom
| | - Nada H Aldahlawi
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
| | - Sally Hayes
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
| | - Keith M Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
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Koppen C, Kreps EO, Anthonissen L, Van Hoey M, Dhubhghaill SN, Vermeulen L. Scleral Lenses Reduce the Need for Corneal Transplants in Severe Keratoconus. Am J Ophthalmol 2018; 185:43-47. [PMID: 29103959 DOI: 10.1016/j.ajo.2017.10.022] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate the success and failure rates of scleral lens correction in severe keratoconus. DESIGN Retrospective case series. METHODS Study population comprised patients with keratoconus who attended the keratoconus clinic at the Antwerp University Hospital, Belgium, between January 1, 2010, and December 31, 2014. The included eyes had maximal keratometry values ≥ 70 diopters, as measured using the sagittal curvature map that was obtained by Scheimpflug tomography. The exclusion criteria included amblyopia, mental retardation, and concomitant ocular disease that limited their visual potential. RESULTS Scleral lens fitting was proposed for the 75 eyes included in the study. Eight eyes underwent transplant surgery because of insufficient visual acuity with the lenses, lens intolerance, and issues with handling the lenses. Twelve eyes did not have lenses fitted because of good visual acuity in the other eye or a contraindication for lens wear. Three eyes were successfully fitted with corneal or hybrid lens wear. Scleral lenses were prescribed in 51 of 75 eyes. The mean gain in visual acuity (lens vs spectacle-corrected visual acuity) was 0.54 ± 0.18 (decimal fraction, Snellen eye chart). Seven eyes were lost to follow-up, 4 eyes abandoned wearing the scleral lens because of an inability to handle the lenses, and 40 eyes wore the lenses at their last follow-up visit, with a mean follow-up interval of 30.15 ± 12.83 months. CONCLUSIONS Forty of the 51 eyes with severe keratoconus that would otherwise have undergone transplant surgery were successfully treated with long-term scleral lens wear. In this way, the indication for keratoplasty was more than halved in our keratoconus population.
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Changes in Corneal Density After Accelerated Corneal Collagen Cross-linking With Different Irradiation Intensities and Energy Exposures: 1-Year Follow-up. Cornea 2017; 36:1331-1335. [PMID: 28872519 DOI: 10.1097/ico.0000000000001362] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE To determine and compare the changes in corneal density after 2 different protocols of accelerated corneal collagen cross-linking (A-CXL) in patients with progressive keratoconus. METHODS Two groups of eyes received A-CXL treatment; 20 eyes received A-CXL using continuous UVA light exposure at 9 mW/cm for 10 minutes with a total energy dose of 5.4 J/cm, and 24 eyes received A-CXL using continuous UVA light exposure at 30 mW/cm for 4 minutes with a total energy dose of 7.2 J/cm. Corneal density was measured with Scheimpflug tomography at 1, 3, 6, and 12 months of follow-up. RESULTS Densitometry peaked at 1 month (mean: 16.34 ± 3.80, P = 0.006, 9-mW/cm A-CXL; mean: 20.90 ± 2.81, P < 0.0001, 30-mw/cm A-CXL) in both groups, and it decreased over time in 30-mW/cm A-CXL. However, in 9-mW/cm A-CXL, increased corneal densitometry plateaued until 6 months postoperatively and started to decrease thereafter. Densitometry completely returned to baseline after 12 months in both groups. The mean change in density at 1- and 3-month follow-up was higher in the 30-mW A-CXL group than in the 9-mW A-CXL group (P = 0.003, P = 0.044; respectively). CONCLUSIONS High-energy exposure tends to induce more haze in the early posttreatment period, but it is reversible.
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Naderan M, Jahanrad A. Topographic, tomographic and biomechanical corneal changes during pregnancy in patients with keratoconus: a cohort study. Acta Ophthalmol 2017; 95:e291-e296. [PMID: 27781383 DOI: 10.1111/aos.13296] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 09/16/2016] [Indexed: 11/30/2022]
Abstract
PURPOSE This study aimed at evaluating the effect of pregnancy on topographic, tomographic and biomechanical parameters of patients with keratoconus (KC) in comparison with non-pregnant patients with KC. METHOD In a cohort study, patients with KC, whose disease was stable for at least 2 years, were evaluated before pregnancy, at their third trimester of pregnancy (34th week of pregnancy) and 6 months after pregnancy. As the control group, an equivalent number of age- and severity-matched non-pregnant female patients with KC were evaluated at the corresponding times. All subjects were evaluated with respect to central and thinnest corneal thickness (CCT and TCT), keratometry values, and maximum anterior and posterior elevation measurements (AE and PE) by Pentacam. Furthermore, corneal biomechanical properties including corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the ocular response analyser. RESULTS Twenty-two eyes of 11 patients were equally enrolled in each group. The results revealed that there was a statistically significant difference between the means of all measurements during the course of study (p < 0.001, repeated measures analysis of variance). The values of CCT, TCT, CH, CRF, IOPg and IOPcc were significantly decreased; however, keratometry values, AE, PE and refraction measurements were significantly increased during the study period (p < 0.001). In contrast, no significant differences were observed regarding the study variables in the control group (p > 0.05). According to the Amsler-Krumeich classification, severity of KC increased during the pregnancy and postpregnancy periods (p = 0.038). CONCLUSION The obtained results revealed that KC progressed during the pregnancy period and continued to the post-partum period, indicating that pregnancy may be a risk factor for KC progression. Patients with KC, who intend to become pregnant, may consider corneal cross-linking treatment in an attempt to stop KC progression.
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Affiliation(s)
- Mohammad Naderan
- School of Medicine; Tehran University of Medical Sciences; Tehran Iran
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Ghosh S, Mutalib HA, Sharanjeet-Kaur, Ghoshal R, Retnasabapathy S. Effects of contact lens wearing on keratoconus: a confocal microscopy observation. Int J Ophthalmol 2017; 10:228-234. [PMID: 28251081 DOI: 10.18240/ijo.2017.02.08] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 06/12/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To evaluate the corneal cell morphology of new keratoconus patients wearing two different types of rigid gas-permeable (RGP) contact lenses for 1y. METHODS Thirty nine eyes of 39 new keratoconus patients were selected and randomly fitted with two types of RGP contact lenses. Group 1 had 21 eyes with regular rigid gas-permeable (RRGP) contact lens and rest 18 eyes were in group 2 with specially designed rigid gas-permeable (SRGP) contact lens. Corneal cell morphology was evaluated using a slit scanning confocal microscope at no-lens wear and after 1y of contact lens wearing. RESULTS After 1y of contact lens wearing in group 1, the mean anterior and posterior stromal keratocyte density were significantly less (P=0.006 and P=0.001, respectively) compared to no-lens wear. The mean cell area of anterior and posterior stromal keratocyte were also significantly different (P=0.005 and P=0.001) from no-lens wear. The anterior and posterior stromal haze increased by 18.74% and 23.81%, respectively after 1y of contact lens wearing. Whereas in group 2, statistically significant changes were observed only in cell density & area of anterior stroma (P=0.001 and P=0.001, respectively) after 1y. While, level of anterior and posterior stromal haze increased by 16.67% and 11.11% after 1y of contact lens wearing. Polymegathism and pleomorphism also increased after 1y of contact lens wearing in both the contact lens groups. CONCLUSION Confocal microscopy observation shows the significant alterations in corneal cell morphology of keratoconic corneas wearing contact lenses especially in group 1. The type of contact lens must be carefully selected to minimize changes in corneal cell morphology.
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Affiliation(s)
- Somnath Ghosh
- Optometry and Visual Sciences Program, Faculty of Health Sciences, University Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia
| | - Haliza A Mutalib
- Optometry and Visual Sciences Program, Faculty of Health Sciences, University Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia
| | - Sharanjeet-Kaur
- Optometry and Visual Sciences Program, Faculty of Health Sciences, University Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia
| | - Rituparna Ghoshal
- Optometry and Visual Sciences Program, Faculty of Health Sciences, University Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia
| | - Shamala Retnasabapathy
- Department of Ophthalmology, Hospital Sungai Buloh, Jalan Hospital, Sungai Buloh 47000, Malaysia
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Keraring implantation using the Zeiss Visumax femtosecond laser in the management of patients with keratoconus. Eye (Lond) 2017; 31:916-923. [PMID: 28234352 DOI: 10.1038/eye.2017.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 12/01/2016] [Indexed: 11/08/2022] Open
Abstract
PurposeTo evaluate the safety and efficacy of implanted Kerarings in patients with mild, moderate, and severe keratoconus.Patients and methodsA 12-month retrospective case series of 70 eyes of 70 patients who underwent Keraring implantation with the Zeiss Visumax femtosecond laser. Patients were stratified into three groups according to their topography as mild (mean K <48 D) moderate (48-55 D) or severe (>55 D). Main outcome measures were visual acuity, manifest refraction, and corneal topography. Complications were recorded.ResultsA total of 66 patients completed the 12-month follow-up. In all, 4 rings were explanted, 3 due to no improvement in visual function and 1 due to corneal neovascularization. Also, 4 rings were repositioned. In mild disease (n=28), BCVA increased to 0.10 logMAR, sphere decreased to -1.54 D, cylinder decreased to 2.54 D, Kmax decreased to 46.25 D, and keratometric astigmatism to 3.88 D (P<0.01 for each compared with preoperative values). No patients lost vision. In moderate disease (n=27), sphere decreased to -4.06 D, cylinder decreased to 3.47 D, Kmax decreased to 51.69 D, and keratometric astigmatism to 4.56 D (P<0.05 for each compared with preoperative values). In severe disease (n=11), BCVA increased to 0.34 logMAR, Kmax decreased to 57.65 D, and keratometric astigmatism to 5.07 D (P<0.05 for each compared with preoperative values).ConclusionFemtosecond laser-assisted Keraring implantation is a safe and minimally invasive treatment option to improve the refraction and visual function in patients with keratoconus. Patients with mild keratoconus are more likely to have a favourable outcome following Keraring implantation.
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Barsam A, Brennan N, Petrushkin H, Xing W, Quartilho A, Bunce C, Foot B, Cartwright NK, Haridas A, Agrawal P, Suleman H, Ahmad S, MacDonald E, Johnston J, Tuft S. Case-control study of risk factors for acute corneal hydrops in keratoconus. Br J Ophthalmol 2016; 101:499-502. [PMID: 27388247 DOI: 10.1136/bjophthalmol-2015-308251] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 05/09/2016] [Accepted: 06/19/2016] [Indexed: 11/03/2022]
Abstract
PURPOSE To determine risk factors for the development of acute corneal hydrops in keratoconus in the UK in a case-controlled study. METHODS Between November 2009 and December 2010, we prospectively identified 73 individuals who developed acute corneal hydrops. We then identified 174 controls from nine regions in the UK with keratoconus who had not had hydrops. For cases and controls we recorded demographics and clinical features. Univariate and multivariable logistic regressions were performed to identify risk factors. RESULTS Univariate analysis suggested strong associations between the odds of hydrops and each of vernal keratoconjunctivitis (OR 4.08, 95% CI 1.45 to 11.49, p=0.008), asthma (OR 2.70, CI 1.34 to 5.47, p=0.006), atopic dermatitis (OR 3.13, CI 1.50 to 6.56, p=0.002), learning difficulties (OR 7.84, CI 2.86 to 21.46, p<0.001), previous hydrops (OR 40.2; CI 6.2 to ∞, p<0.001), black ethnicity (OR 2.98, CI 0.98 to 8.99; p=0.05), visual acuity in the worse eye (OR 8.76 CI 3.86 to 19.88; p<0.001) and minimum keratometry of ≥48 D prior to the hydrops (OR 4.91, CI 1.07 to 22.6, p=0.041). The use of a contact lens correction was also found to be associated with the odds of hydrops (OR 0.08; CI 0.03 to 0.19, p<0.001). Multiple variable regression indicated that having vernal keratoconjunctivitis (adjusted OR (AOR) 15, 95% CI 1.30 to 173.7; p=0.03), asthma (AOR 4.92, CI 1.22 to 19.78; p=0.025), visual acuity in worse eye (AOR 4.11, CI 1.18 to 14.32; p=0.026) and a high keratometry value (AOR 4.44, CI 0.85 to 23.18; p=0.077) were independently associated with the odds of hydrops in subjects with keratoconus. CONCLUSION Some individuals with keratoconus are at high risk of developing acute corneal hydrops. These patients could be managed more aggressively to reduce their risk of developing this complication of their disease.
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Affiliation(s)
- Allon Barsam
- Luton and Dunstable Hospital NHS Foundation Trust, Luton, UK
| | - Nic Brennan
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Harry Petrushkin
- Clinical and Diagnostic Oral Sciences, Queen Mary University of London, London, UK
| | - Wen Xing
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Quartilho
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Catey Bunce
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Barny Foot
- British Ophthalmic Surveillance Unit, Royal College of Ophthalmologists, London, UK
| | | | - Anjana Haridas
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Pavi Agrawal
- Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Hanif Suleman
- Division of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham, UK
| | - Sajjad Ahmad
- Royal Liverpool University Hospital, Liverpool, UK
| | | | | | - Stephen Tuft
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
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Prakash G, Philip R, Srivastava D, Bacero R. Evaluation of the Robustness of Current Quantitative Criteria for Keratoconus Progression and Corneal Cross-linking. J Refract Surg 2016; 32:465-72. [DOI: 10.3928/1081597x-20160506-01] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/22/2016] [Indexed: 11/20/2022]
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Sequential Intracorneal Ring Segment Implantation and Corneal Transepithelial Collagen Cross-Linking in Keratoconus. Cornea 2016; 34:1420-6. [PMID: 26356750 DOI: 10.1097/ico.0000000000000600] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To assess the clinical outcomes after sequential surgical implantation of intracorneal ring segments and transepithelial corneal collagen cross-linking (TE-CXL) in keratoconic eyes. METHODS In this consecutive randomized study, 40 eyes of 29 patients with progressive mild to moderate keratoconus were included and were randomly divided into two groups. Group 1 included 20 eyes that underwent Keraring implantation, and group 2 included 20 eyes that underwent Keraring insertion followed by TE-CXL 1 month later. In both groups, channel creation was performed manually. Visual, refractive, and topographic outcomes were measured preoperatively and 1, 3, and 6 months postoperatively. RESULTS There was statistically significant improvement in both groups regarding uncorrected distance visual acuity (P < 0.001) and corrected distance visual acuity (P < 0.001), with a significant reduction in the refractive error and keratometric values (P < 0.001). There was no statistically significant difference between both groups regarding changes in uncorrected distance visual acuity, corrected distance visual acuity, and refractive error (P > 0.05). However, group 2 revealed a more statistically significant reduction in spherical refraction after 3 months (P = 0.04) and highly significant improvement after 6 months (P = 0.004). CONCLUSIONS Intracorneal ring segment implantation is an effective procedure for visual and refractive improvement in keratoconic eyes. The addition of TE-CXL to the procedure compensates for residual superficial irregularities, disrupts the progression of the disease, and provides greater improvements in spherical values. The process is simply a deep stretch with superficial lamellar stiffness.
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The Superficial Stromal Scar Formation Mechanism in Keratoconus: A Study Using Laser Scanning In Vivo Confocal Microscopy. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7092938. [PMID: 26885515 PMCID: PMC4739471 DOI: 10.1155/2016/7092938] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/05/2015] [Accepted: 12/13/2015] [Indexed: 11/25/2022]
Abstract
To investigate the mechanism of superficial stromal scarring in advanced keratoconus using confocal microscopy, the keratocyte density, distribution, micromorphology of corneal stroma, and SNP in three groups were observed. Eight corneal buttons of advanced keratoconus were examined by immunohistochemistry. The keratocyte densities in the sub-Bowman's stroma, anterior stroma, and posterior stroma and the mean SNP density were significantly different among the three groups. In the mild-to-moderate keratoconus group, activated keratocyte nuclei and comparatively highly reflective ECM were seen in the sub-Bowman's stroma, while fibrotic structures with comparatively high reflection were visible in the anterior stroma in advanced keratoconus. The alternating dark and light bands in the anterior stroma of the mild-to-moderate keratoconus group showed great variability in width and direction. The wide bands were localized mostly in the posterior stroma that corresponded to the Vogt striae in keratoconus and involved the anterior stroma only in advanced keratoconus. Histopathologically, high immunogenicity of α-SMA, vimentin, and FAP was expressed in the region of superficial stromal scarring. In vivo confocal microscopy revealed microstructural changes in the keratoconic cone. The activation of superficial keratocytes and abnormal remodeling of ECM may both play a key role in the superficial stromal scar formation in advanced keratoconus.
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Evaluation of Intrastromal Riboflavin Concentration in Human Corneas after Three Corneal Cross-Linking Imbibition Procedures: A Pilot Study. J Ophthalmol 2015; 2015:794256. [PMID: 26858842 PMCID: PMC4709688 DOI: 10.1155/2015/794256] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/11/2015] [Accepted: 12/13/2015] [Indexed: 11/17/2022] Open
Abstract
Purpose. To compare stromal riboflavin concentration after three corneal cross-linking (CXL) imbibition procedures: standard (EpiOff), transepithelial corneal (EpiOn), and iontophoresis-assisted technique (Ionto) using 0.1% hypotonic riboflavin phosphate. Methods. Randomized open-label pilot clinical study. Twelve corneas/12 patients with advanced keratoconus were randomly divided into 4 groups for CXL (n = 3). The corneas underwent imbibition with standard riboflavin EpiOff and with enhanced riboflavin solution (RICROLIN+) EpiOff, EpiOn, and iontophoresis techniques. Thereafter, deep anterior lamellar keratectomy procedure was performed and the obtained debrided corneal tissues were frozen. The maximal intrastromal riboflavin concentration was measured by high-performance liquid chromatography/mass spectrometry (mcg/dg). Results. The mean stromal concentration of riboflavin was 2.02 ± 0.72 mcg/dg in EpiOff group, 4.33 ± 0.12 mcg/g in EpiOff-RICROLIN+ group, 0.63 ± 0.21 mcg/dg in EpiOn-RICROLIN+ group, and 1.15 ± 0.27 mcg/dg in iontophoresis RICROLIN+ group. A 7-fold decrease in intrastromal riboflavin concentration was observed comparing EpiOn-RICROLIN+ and EpiOff-RICROLIN+ groups. Conclusion. The present pilot study indicates that both transepithelial CXL techniques in combination with hypotonic enhanced riboflavin formulation (RICROLIN+) were still inferior to the standard CXL technique; however, larger clinical studies to further validate the results are needed and in progress.
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One-Year Clinical Outcomes of a Two-Step Surgical Management for Keratoconus—Topography-Guided Photorefractive Keratectomy/Cross-Linking After Intrastromal Corneal Ring Implantation. Eye Contact Lens 2015; 41:359-66. [DOI: 10.1097/icl.0000000000000135] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yildiz EH, Erdurmus M, Elibol ES, Acar B, Vural ET. Contact lens impact on quality of life in keratoconus patients: rigid gas permeable versus soft silicone-hydrogel keratoconus lenses. Int J Ophthalmol 2015; 8:1074-7. [PMID: 26558228 DOI: 10.3980/j.issn.2222-3959.2015.05.38] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 02/05/2015] [Indexed: 11/02/2022] Open
Abstract
AIM To determine the impact of rigid gas permeable (RGP) and silicone-hydrogel keratoconus lenses on the quality of life (QoL) in keratoconus (KCN) patients using the self-reported results from the Contact Lens Impact on Quality of Life (CLIQ) Questionnaire. METHODS From January 2013 to April 2013, 27 consecutive KCN patients who wore RGP contact lenses (conflexair100 UV KE Zeiss-Wöhlk) or soft silicone-hydrogel contact lenses (SHCLs) for KCN (KeraSoft IC- Bausch&Lomb or Hydrocone Toris K-Swiss lens) completed the CLIQ questionnaire. RESULTS The mean age of 27 patients was 29.6±8.0y. Fifteen patients were RGP user. The groups were comparable with respect to the mean patient age, sex, and mean K values (P=0.1, P=0.8 and P=0.1, respectively). The mean CLIQperson measure was 42.8±5.5 in RGP group and 39.6±5.5 in SHCLs for KCN group (P=0.06). CLIQperson measure was positively correlated with steep K value (r=0.301, P=0.04). When eyes were stratified by visual acuity with contact lenses, the mean CLIQperson measure was 42.01±5.6 in eyes with a visual acuity of 20/20-20/25 (n=44) and 38.4±5.26 in eyes with a visual acuity of 20/32 or less (n=10; P=0.097). CONCLUSION RGP lenses and SHCLs for KCN have similar impact on QoL.
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Affiliation(s)
- Elvin Hatice Yildiz
- Department of Ophthalmology, Ministry of Healthy, Haydarpasa Numune Training and Research Hospital, Istanbul 34668, Turkey
| | - Mesut Erdurmus
- Department of Ophthalmology, Bolu Abant Izzet Baysal School of Medicine, Bolu 14280, Turkey
| | - Emine Savran Elibol
- Department of Ophthalmology, Ministry of Healthy, Haydarpasa Numune Training and Research Hospital, Istanbul 34668, Turkey
| | - Banu Acar
- Department of Ophthalmology, Ministry of Healthy, Haydarpasa Numune Training and Research Hospital, Istanbul 34668, Turkey
| | - Ece Turan Vural
- Department of Ophthalmology, Ministry of Healthy, Haydarpasa Numune Training and Research Hospital, Istanbul 34668, Turkey
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The influence of the refractive correction on the vision-related quality of life in keratoconus patients. Qual Life Res 2015; 25:1043-51. [DOI: 10.1007/s11136-015-1117-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2015] [Indexed: 11/25/2022]
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Brown SE, Simmasalam R, Antonova N, Gadaria N, Asbell PA. Progression in keratoconus and the effect of corneal cross-linking on progression. Eye Contact Lens 2015; 40:331-8. [PMID: 25320958 DOI: 10.1097/icl.0000000000000085] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Ultraviolet corneal collagen cross-linking (CXL) has been shown to possibly delay, halt, or even reverse disease progression in keratoconus. Understanding of keratoconic progression in untreated eyes, however, is still incomplete and is hampered by the varying definitions and metrics used to evaluate corneal changes. As a result, the CXL literature varies widely in criteria for progression and parameters for successful outcomes. To date, there have been few long-term, well-controlled clinical trials supporting the efficacy of CXL to prevent progression in keratoconus. Review of our data on keratoconus suggests the course of corneal change is difficult to predict and that many keratoconic eyes appear stable once the eyes begin to exhibit frank changes in corneal curvature typical of keratoconus. Better-defined metrics for progression in keratoconus are needed. Larger, long-term randomized clinical trials may more clearly establish the efficacy and safety of CXL in the management of keratoconus and determine which patients are the best candidates for this procedure.
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Affiliation(s)
- Sarah E Brown
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY
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Sykakis E, Karim R, Evans JR, Bunce C, Amissah‐Arthur KN, Patwary S, McDonnell PJ, Hamada S. Corneal collagen cross-linking for treating keratoconus. Cochrane Database Syst Rev 2015; 2015:CD010621. [PMID: 25803325 PMCID: PMC10645161 DOI: 10.1002/14651858.cd010621.pub2] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Keratoconus is a condition of the eye that affects approximately 1 in 2000 people. The disease leads to a gradual increase in corneal curvature and decrease in visual acuity with consequent impact on quality of life. Collagen cross-linking (CXL) with ultraviolet A (UVA) light and riboflavin (vitamin B2) is a relatively new treatment that has been reported to slow or halt the progression of the disease in its early stages. OBJECTIVES The objective of this review was to assess whether there is evidence that CXL is an effective and safe treatment for halting the progression of keratoconus compared to no treatment. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 7), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2014), EMBASE (January 1980 to August 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to August 2014), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to August 2014), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organisation International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We used no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 August 2014. SELECTION CRITERIA We included randomised controlled trials (RCTs) where CXL with UVA light and riboflavin was used to treat people with keratoconus and was compared to no treatment. DATA COLLECTION AND ANALYSIS Two review authors independently screened the search results, assessed trial quality, and extracted data using standard methodological procedures expected by Cochrane. Our primary outcomes were two indicators of progression at 12 months: increase in maximum keratometry of 1.5 dioptres (D) or more and deterioration in uncorrected visual acuity of more than 0.2 logMAR. MAIN RESULTS We included three RCTs conducted in Australia, the United Kingdom, and the United States that enrolled a total of 225 eyes and analysed 219 eyes. The total number of people enrolled was not clear in two of the studies. Only adults were enrolled into these studies. Out of the eyes analysed, 119 had CXL (all using the epithelium-off technique) and 100 served as controls. One of these studies only reported comparative data on review outcomes. All three studies were at high risk for performance bias (lack of masking), detection bias (only one trial attempted to mask outcome assessment), and attrition bias (incomplete follow-up). It was not possible to pool data due to differences in measuring and reporting outcomes. We identified a further three unpublished trials that potentially had enrolled a total of 195 participants.There was limited evidence on the risk of progression. Analysis of the first few participants followed up to one year in one study suggested that eyes given CXL were less likely to have an increase in maximum keratometry of 1.5 D or more at 12 months compared to eyes given no treatment, but the confidence intervals (CI) were wide and compatible with no effect or more progression in the CXL group (risk ratio (RR) 0.12, 95% CI 0.01 to 2.00, 19 eyes). The same study reported the number of eyes with an increase of 2 D or more at 36 months in the whole cohort with a RR of 0.03 favouring CXL (95% CI 0.00 to 0.43, 94 eyes). Another study reported "progression" at 18 months using a different definition; people receiving CXL were less likely to progress, but again the effect was uncertain (RR 0.14, 95% CI 0.01 to 2.61, 44 eyes). We judged this to be very low-quality evidence due to the risk of bias of included studies, imprecision, indirectness and publication bias but noted that the size of the potential effect was large.On average, treated eyes had a less steep cornea (approximately 2 D less steep) (mean difference (MD) -1.92, 95% CI -2.54 to -1.30, 94 eyes, 1 RCT, very low-quality evidence) and better uncorrected visual acuity (approximately 2 lines or 10 letters better) (MD -0.20, 95% CI -0.31 to -0.09, 94 eyes, 1 RCT, very low-quality evidence) at 12 months. None of the studies reported loss of 0.2 logMAR acuity. The data on corneal thickness were inconsistent. There were no data available on quality of life or costs. Adverse effects were not uncommon but mostly transient and of low clinical significance. In one trial, 3 out of 12 participants treated with CXL had an adverse effect including corneal oedema, anterior chamber inflammation, and recurrent corneal erosions. In one trial at 3 years 3 out of 50 participants experienced adverse events including mild diffuse corneal oedema and paracentral infiltrate, peripheral corneal vascularisation, and subepithelial infiltrates and anterior chamber inflammation. No adverse effects were reported in the control groups. AUTHORS' CONCLUSIONS The evidence for the use of CXL in the management of keratoconus is limited due the lack of properly conducted RCTs.
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Affiliation(s)
- Evripidis Sykakis
- Queen Victoria HospitalCorneoplastic Unit and Eye BankEast GrinsteadUK
| | - Rushmia Karim
- Moorfields Eye Hospital NHS Foundation TrustLondonUK
| | - Jennifer R Evans
- London School of Hygiene & Tropical MedicineCochrane Eyes and Vision Group, ICEHKeppel StreetLondonUKWC1E 7HT
| | - Catey Bunce
- Moorfields Eye Hospital NHS Foundation TrustResearch and Development DepartmentCity RoadLondonUKEC1V 2PD
| | | | - Showrob Patwary
- Birmingham and Midland Eye CentreDudley RoadBirminghamUKB18 7QH
| | | | - Samer Hamada
- Queen Victoria HospitalCorneoplastic Unit and Eye BankEast GrinsteadUK
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Romano V, Iovieno A, Parente G, Soldani AM, Fontana L. Long-term clinical outcomes of deep anterior lamellar keratoplasty in patients with keratoconus. Am J Ophthalmol 2015; 159:505-11. [PMID: 25486540 DOI: 10.1016/j.ajo.2014.11.033] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/22/2014] [Accepted: 11/28/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To report long-term clinical outcomes of deep anterior lamellar keratoplasty (DALK) in patients with keratoconus. DESIGN Retrospective noncomparative interventional study. METHODS setting: Single center. patients: Total of 158 eyes/150 consecutive patients with keratoconus with postoperative follow-up time equal to or greater than 4 years. intervention: DALK. main outcome measure(s): Uncorrected and corrected distance visual acuity (UDVA, CDVA), mean refractive spherical equivalent (MRSE), keratometry, endothelial cell density (ECD). RESULTS Mean postoperative follow-up was 76.9 ± 23.2 (range 48-120) months. Preoperative UDVA was 20/400 (1.5 ± 0.4 logMAR), CDVA 20/50 (0.7 ± 0.2 logMAR), MRSE -11.1 ± 5.6 diopters (D), mean keratometry 60.7 ± 6.1 D, topographic astigmatism 4.7 ± 2.6 D. At last postoperative follow-up visit, UDVA improved to 20/50 (0.5 ± 0.3 logMAR), CDVA to 20/25 (0.09 ± 0.1 logMAR), MRSE to -2.6 ± 3.5 D, mean keratometry to 44.4 ± 2.2 D, and topographic astigmatism to 2.9 ± 1.3 D. Postoperative ECD did not vary from preoperative values being 2070.5 ± 367.5 cell/mm(2) and 2198 ± 373 cell/mm(2), respectively, with 70% of eyes (111/158) showing ECD ≥2000 cells/mm(2). Eighteen eyes (11.3 %) developed stromal or epithelial rejection, 3 (1.8%) required regrafting. Eyes with successful big bubble showed greater CDVA than those that required manual dissection at follow-up equal to or less than 5 years but comparable results in the longer term. CONCLUSIONS DALK provides stable long-term visual and refractive outcomes. Risk of graft rejection, postoperative complication, and late ECD decay is reduced when compared to standard penetrating keratoplasty.
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Affiliation(s)
- Vito Romano
- Eye Unit, Arcispedale Santa Maria Nuova - Istituto di Ricovero e Cura a Carattere Scientifico (ASMN-IRCCS), Reggio Emilia, Italy.
| | - Alfonso Iovieno
- Eye Unit, Arcispedale Santa Maria Nuova - Istituto di Ricovero e Cura a Carattere Scientifico (ASMN-IRCCS), Reggio Emilia, Italy
| | | | - Anna Maria Soldani
- Eye Unit, Arcispedale Santa Maria Nuova - Istituto di Ricovero e Cura a Carattere Scientifico (ASMN-IRCCS), Reggio Emilia, Italy
| | - Luigi Fontana
- Eye Unit, Arcispedale Santa Maria Nuova - Istituto di Ricovero e Cura a Carattere Scientifico (ASMN-IRCCS), Reggio Emilia, Italy
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Efficacy and safety of deep anterior lamellar keratoplasty vs. penetrating keratoplasty for keratoconus: a meta-analysis. PLoS One 2015; 10:e0113332. [PMID: 25633311 PMCID: PMC4310590 DOI: 10.1371/journal.pone.0113332] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 10/27/2014] [Indexed: 01/11/2023] Open
Abstract
Purpose To evaluate difference in therapeutic outcomes between deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) for the clinical treatment of keratoconus. Methods A comprehensive search was conducted in Pubmed, EMBASE, Cochrane Library, and Web of science. Eligible studies should include at least one of the following factors: best corrected visual acuity (BCVA), postoperative spherical equivalent (SE), postoperative astigmatism and endothelial cell count (ECC), central corneal thickness (CCT), graft rejection and graft failure, of which BCVA, graft rejection and graft failure were used as the primary outcome measures, and postoperative SE, astigmatism, CCT and ECC as the secondary outcome measures. Given the lack of randomized clinical trials (RCTs), cohort studies and prospective studies were considered eligible. Results Sixteen clinical trials involving 6625 eyes were included in this review, including 1185 eyes in DALK group, and 5440 eyes in PKP group. The outcomes were analyzed using Cochrane Review Manager (RevMan) version 5.0 software. The postoperative BCVA in DALK group was significantly better than that in PKP group (OR = 0.48; 95%CI 0.39 to 0.60; p<0.001). There were fewer cases of graft rejection in DALK group than those in PKP group (OR = 0.28; 95%CI 0.15 to 0.50; p<0.001). Nevertheless the rate of graft failure was similar between DALK and PKP groups (OR = 1.05; 95%CI 0.81 to 1.36; p = 0.73). There were no significant differences in the secondary outcomes of SE (p = 0.70), astigmatism (p = 0.14) and CCT (p = 0.58) between DALK and PKP groups. And ECC in DALK group was significantly higher than PKP group (p<0.001). The postoperative complications, high intraocular pressure (high-IOP) and cataract were analyzed, fewer cases of complications occurred in DALK group than those in PKP group (high-IOP, OR 0.22, 95% CI 0.11–0.44, P<0.001) (cataract, OR 0.22; 95% CI 0.08–0.61, P = 0.004). And no cases of expulsive hemorrhage and endophthalmitis were reported. Conclusion The visual outcomes for DALK were not equivalent to PKP. The rate of graft failure was similar between DALK and PKP. Fewer postoperative complications occurred in DALK group, indicating that compared with PKP, DALK has lower efficacy but higher safety.
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Craig JA, Mahon J, Yellowlees A, Barata T, Glanville J, Arber M, Mandava L, Powell J, Figueiredo F. Epithelium-Off Photochemical Corneal Collagen Cross-Linkage Using Riboflavin and Ultraviolet A for Keratoconus and Keratectasia: A Systematic Review and Meta-Analysis. Ocul Surf 2014; 12:202-14. [DOI: 10.1016/j.jtos.2014.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 05/01/2014] [Accepted: 05/02/2014] [Indexed: 01/23/2023]
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Ozgurhan EB, Celik U, Bozkurt E, Demirok A. Evaluation of subbasal nerve morphology and corneal sensation after accelerated corneal collagen cross-linking treatment on keratoconus. Curr Eye Res 2014; 40:484-9. [PMID: 24979260 DOI: 10.3109/02713683.2014.932387] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The aim of this study was to report on the evaluation of corneal nerve fiber density and corneal sensation after accelerated corneal collagen cross-linking on keratoconus patients. METHODS The study was performed on 30 keratoconus eyes (30 participants: 16 M, 14 F; 17-32 years old) treated with accelerated collagen cross-linking for disease stabilization. Mean outcome measures were corneal sensation evaluation by Cochet-Bonnet esthesiometry and subbasal nerve fiber density assessment by corneal in vivo confocal microscopy. All corneal measurements were performed using scanning slit confocal microscopy (ConfoScan 4, Nidek Technologies, Padova, Italy). RESULTS The accelerated corneal collagen cross-linking procedure was performed on 30 eyes of 30 patients (19 right, 63.3%; 11 left, 27.7%). The mean age was 23.93 ± 4. The preoperative mean keratometry, apex keratometry and pachymetry values were 47.19 ± 2.82 D, 56.79 ± 5.39 and 426.1 ± 25.6 μm, respectively. Preoperative mean corneal sensation was 56.3 ± 5.4 mm (with a range from 40 to 60 mm), it was significantly decreased at 1st and 3rd month visit and increased to preoperative values after 6th month visit. Preoperative mean of subbasal nerve fiber density measurements was 22.8 ± 9.7 nerve fiber/mm(2) (with a range of 5-45 mm), it was not still at the preoperative values at 6th month (p = 0.0001), however reached to the preoperative values at 12th month (p = 0.914). CONCLUSIONS Subbasal nerve fibers could reach the preoperative values at the 12th month after accelerated corneal collagen cross-linking treatment although the corneal sensation was improved at 6th month. These findings imply that the subjective healing process is faster than the objective evaluation of the keratoconus patients' cornea treated with accelerated corneal collagen cross-linking.
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Affiliation(s)
- Engin Bilge Ozgurhan
- Refractive Surgery, Beyoglu Eye Training and Research Hospital , Istanbul , Turkey and
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Abstract
Keratoconus is a progressive, ectatic disease of the cornea leading to thinning and highly irregular astigmatism. Until recently all treatment options, such as prescription of glasses or contact lenses were symptomatic and neither keratoplasty nor the implantation of intracorneal rings can heal the disease. Riboflavin ultraviolet A (UVA) collagen cross-linking (CXL) cannot heal keratoconus either but promises to halt the progression. The therapeutic principle is a photochemical reaction of riboflavin and UVA light leading to free oxygen radicals in the corneal stroma that induce covalent linking of the collagen fibrils. This stiffening effect should stop the progression. After the first reports at the end of the 1990s the treatment was widely used and many case series show that CXL can be effective in stopping disease progression in some patients. However, randomized, controlled multicenter trials showing high evidence of the treatment effectiveness are rare. This report includes a review of the literature regarding treatment effectiveness, indications and new developments.
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Affiliation(s)
- P Maier
- Universitäts-Augenklinik Freiburg, Killianstr. 5, 79106, Freiburg, Deutschland.
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