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Wallerstein A, Gauvin M, Watt H, Trang N, Trottier P, Adiguzel E, Cohen M. Does Adjunctive Under-flap CXL Reduce Regression for Hyperopic LASIK? J Refract Surg 2022; 38:770-779. [PMID: 36476303 DOI: 10.3928/1081597x-20221026-05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE To investigate whether adding accelerated under-flap corneal cross-linking to hyperopic laser in situ keratomileusis (LASIK-ufCXL) affects postoperative stability and regression, visual and refractive outcomes, and subjective quality of vision. METHODS This prospective comparative contralateral eye study included 51 patients with hyperopia (102 eyes) who received LASIK-ufCXL in the eye with highest defocus equivalent (DEQ) or randomized when DEQ equal, with the contralateral control eye receiving LASIK alone. After excimer ablation, 0.25% riboflavin was instilled on the stromal bed for 3 minutes. The flap was repositioned, followed by a total irradiation dose of 3.24 J ultraviolet A (UV-A) light administered to the corneal surface, using 18 mW/cm2 UV-A for 3 minutes. Postoperative hyperopic regression (stability) was the primary outcome measure, defined by the difference in spherical equivalent (SEQ) at 1 week and 24 months postoperatively. Secondary measures reported uncorrected distance visual acuity, corrected distance visual acuity, cylinder vector analysis, subjective quality of vision, subjective night vision disturbances, and corneal haze. RESULTS At 24 months, the SEQ stability (P = .4273) and the magnitude of hyperopic regression (P = .5613) did not significantly differ between groups, with a small trend showing hyper-opic regression of 0.50 diopters or greater being less frequent in LASIK-ufCXL eyes. There were no significant differences in accuracy, efficacy, and safety (P > .05), with a small trend of more residual refractive astigmatism in the LASIK-ufCXL group (P = .3216, Cohen's d: -0.29). Subjective quality of vision trended inferior in LASIK-ufCXL eyes (P = .2237, Cohen's d: -0.25), with a greater haze grading (P = .0466, Cohen's d: 0.41). CONCLUSIONS Postoperative regression and stability were statistically equivalent between hyperopic LASIK vs LASIK-ufCXL, with identical safety. There were small clinical trends of lower efficacy, accuracy, and subjective quality of vision in LASIK-ufCXL eyes. [J Refract Surg. 2022;38(12):770-779.].
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Wallerstein A, Gauvin M, Rocha G, Sison R, Korban S, Cohen M. Three-Year Outcomes of Under-flap Stromal Bed CXL for Early Post-LASIK Ectasia. J Refract Surg 2022; 38:511-519. [PMID: 35946998 DOI: 10.3928/1081597x-20220713-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the 36-month clinical outcomes of under-flap stromal bed CXL (ufCXL) and report on its ability to stabilize post-laser in situ keratomileusis (LASIK) ectasia. METHODS This case series included 20 eyes with diagnosed early post-LASIK ectasia treated with ufCXL. Inclusion criteria were early, mild post-LASIK ectasia, defined as new-onset postoperative manifest refraction cylinder of 1.50 diopters (D) or less, with new topographic inferior steepening consistent with ectasia, uncorrected distance visual acuity of 20/40 or better, and corrected distance visual acuity of 20/25 or better. The existing LASIK flap was lifted, 0.25% isotonic riboflavin was applied directly to the stromal bed, the flap was repositioned, and 18 mW/cm2 ultraviolet light was applied for 5 minutes to the corneal flap surface. Post-ufCXL ophthalmic data were compared to pre-ufCXL baseline measurements. RESULTS Visual outcomes were maintained pre-ufCXL to 36 months post-ufCXL, with preserved safety index (P = .6545), efficacy index (P = .4980), spherical equivalent accuracy (P = .1536), defocus equivalent accuracy (P = .1032), central corneal thickness (P = .5196), and corneal irregularity indices at 3 mm (P = .8548) and 5 mm (P = .3399). Refractive astigmatism significantly decreased from 0.83 to 0.55 D pre-ufCXL to post-ufCXL (P = .0439), as did maximum keratometry from 42.40 to 42.00 D pre-ufCXL to post-ufCXL (P = .0420). The ufCXL demarcation line depth was 336 ± 21 µm post-ufCXL, with normal endothelial cell density (2,574 ± 203 cells/mm2). Only 1 of 20 eyes showed evidence of progression of 1.00 D in maximum keratometry. CONCLUSIONS The ufCXL procedure shows promise in stabilizing early post-LASIK ectasia. Visual function, refractive astigmatism, maximum keratometry, and corneal irregularity indices were statistically maintained at 36 months postoperatively. [J Refract Surg. 2022;38(8):511-519.].
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Abstract
Corneal crosslinking has been well-described for the treatment of progressive corneal ectasias. Although the goal of treatment in these conditions is the decrease in the risk of progressive steepening of the cornea, studies have shown that flattening of the cornea is achieved in many cases. This finding has led to the postulation that corneal crosslinking may have a potential role in the primary treatment of myopia, and that targeted approaches with more specialized patterns of treatment may be used as primary treatments for astigmatism and hyperopia. In this review, we provide a summary of the clinical and laboratory-based studies evaluating corneal crosslinking as a primary, solitary, refractive treatment for myopia, hyperopia, and astigmatism. Clinical studies thus far are small case series. The primary benefit of refractive corneal crosslinking seems to be the correction of small myopic or hyperopic refractive errors without the need for corneal incisions or tissue removal.
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Affiliation(s)
- Viral V Juthani
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, USA
| | - Roy S Chuck
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, USA
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September consultation #5. J Cataract Refract Surg 2020; 46:1321-1322. [DOI: 10.1097/01.j.jcrs.0000717552.23812.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Mohammadpour M, Farhadi B, Mirshahi R, Masoumi A, Mirghorbani M. Simultaneous photorefractive keratectomy and accelerated collagen cross-linking in high-risk refractive surgery (Tehran protocol): 3-year outcomes. Int Ophthalmol 2020; 40:2659-2666. [PMID: 32607947 DOI: 10.1007/s10792-020-01447-9] [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: 03/16/2020] [Accepted: 05/23/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate safety and efficacy of performing simultaneous photorefractive keratectomy (PRK) and collagen cross-linking (CXL) in myopic patients with preoperative risk factors for developing keratectasia. METHODS Seventeen eyes of 15 patients with at least one of the following risk factors were recruited: central keratometry (Kmax) between 48 and 50, difference between inferior, superior corneal power (I-S value) between 1.4 and 1.9 and corneal thickness between 450 and 480 µm. Upon final stage of standard PRK, 0.02% mitomycin was applied for 30-50 s, and then, accelerated CXL was performed for 5 min. Pre- and postoperative Oculus Pentacam® imaging for keratometry values, measurement of uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were done for all patients. RESULTS Mean follow-up time was 32.08 ± 7.79 months (range 25-49 months). Mean age of patients was 28.78 ± 3.80 years. Mean postoperative spherical equivalent was + 0.19 ± 0.42 (- 0.5 to + 1.0 [D]). Mean UDVA and CDVA improved from 0.9062 ± 0.485 log MAR and 0.0148 ± 0.043 log MAR to 0.0173 ± 0.040 log MAR and 0.0057 ± 0.023 log MAR, respectively (P = 0.011, P = 0.735). Mild degree of early postoperative stromal haze was seen which did not persist more than 6 months. There was no late stromal haze, corneal ectasia or other major postoperative complication in the follow-up period. CONCLUSION Combined PRK and accelerated CXL is an efficient and safe procedure for high-risk refractive surgery candidates, with no increased risk of persistent corneal haze.
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Affiliation(s)
- Mehrdad Mohammadpour
- Ophthalmology Department, Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, 1336616351, Iran
| | - Behnaz Farhadi
- Ophthalmology Department, Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, 1336616351, Iran
| | - Reza Mirshahi
- Ophthalmology Department, Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, 1336616351, Iran.,Eye Research Center, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Ahmad Masoumi
- Ophthalmology Department, Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, 1336616351, Iran.
| | - Masoud Mirghorbani
- Ophthalmology Department, Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, 1336616351, Iran
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Corneal Total and Epithelial Thickness Measured by Sonogage Ultrasound Pachometry and High-resolution Optical Coherence Tomography. Optom Vis Sci 2020; 97:346-350. [PMID: 32413006 DOI: 10.1097/opx.0000000000001508] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SIGNIFICANCE This research questions the validity of using the Sonogage ultrasound (US) pachometer to measure corneal epithelial thickness and coincidentally provides confirmation for the conventional view of the mechanism of orthokeratology (OK) based on central epithelial thinning. PURPOSE The Sonogage (Corneo-Gage Plus 1) pachometer uses A-scan US to measure total corneal thickness. It is claimed that this instrument can also measure corneal epithelial thickness. We sought to validate this claim by comparing total and epithelial thickness measurements with the Sonogage with those obtained with high-resolution optical coherence tomography (OCT). METHODS Fourteen non-contact lens wearers and 14 subjects who had worn Paragon CRT OK lenses overnight for greater than 1 month were recruited. Three OCT and five US measurements were taken in one eye of each subject. Depending on normality of data, paired t tests or Wilcoxon tests were used to compare total and epithelial thicknesses measured with the Sonogage pachometer and the Tomey Casia OCT. Pearson or Spearman correlation analyses were used to examine relationships between measurements obtained with the two instruments. RESULTS There was a significant difference in total corneal thickness measurements between the two instruments. Although a significant correlation was found (r = 0.916, P < .001), the Sonogage consistently measured greater total corneal thickness than did the OCT (+19.5 ± 9.2 μm; P < .001). Epithelial thickness using the Sonogage showed little variation (range, 46.4 to 50.0 μm), whereas epithelial thickness using the OCT ranged from 30.7 to 54.7 μm. There was no significant correlation between epithelial thicknesses obtained with the two instruments (r = -0.135, P = .49). Epithelial thickness measured by OCT was significantly thinner in OK wearers (35.8 ± 2.8 μm) than in nonlens wearers (46.7 ± 4.5 μm, P < .001). CONCLUSIONS The Sonogage is not able to measure epithelial thickness in vivo, returning essentially identical measurements over a range of epithelial thicknesses. Optical coherence tomography measurements confirm the conventional view of the mechanism of OK based on central epithelial thinning.
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Liao C, Lin X, Keel S, Ha J, Yang X, He M. Effects of corneal crosslinking on corneal shape stabilization after orthokeratology. Sci Rep 2020; 10:2357. [PMID: 32047218 PMCID: PMC7012905 DOI: 10.1038/s41598-020-59157-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 01/06/2020] [Indexed: 12/04/2022] Open
Abstract
Orthokeratology (Ortho-K) works to reshape cornea and is the only non-surgical way to enable vision without corrective aids. However, its effect is only temporary, and successful stabilization requires ongoing Ortho-K wear to maintain the reshaping effect. Corneal crosslinking (CXL) is a commonly-used technique in clinical practice to stabilize corneal shape in keratoconic eyes. However, whether or not CXL can stabilize corneal shape after Ortho-K in normal cornea has not been reported. Therefore, this proof-of-concept study using 2 rhesus monkeys aimed to determine the efficacy of the combined procedure. One monkey wore Ortho-K bilaterally for 24 hours, and the other from 6 pm to 8 am for 7 days. The left eyes of both monkeys underwent CXL after Ortho-K while the contralateral eye served as control. Results showed a gradual regression of corneal shape in all eyes with or without CXL. However, eyes underwent CXL regressed more slowly than the control eyes. The control eyes and the CXL treatment eye in the 7-day Ortho-K monkey regressed completely at last, while the CXL treatment eye in the 24 h Ortho-K monkey maintained a corneal flattening of −1.48 D 27 days after procedure. These findings suggest CXL can slow the regression of Ortho-K for a short duration, but cannot sustain its effect according to the current protocol.
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Affiliation(s)
- Chimei Liao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xingyan Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Stuart Keel
- Center for Eye Research Australia; Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Jason Ha
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Australia
| | - Xiao Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
| | - Mingguang He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
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Mercatelli R, Mattana S, Capozzoli L, Ratto F, Rossi F, Pini R, Fioretto D, Pavone FS, Caponi S, Cicchi R. Morpho-mechanics of human collagen superstructures revealed by all-optical correlative micro-spectroscopies. Commun Biol 2019; 2:117. [PMID: 30937399 PMCID: PMC6435656 DOI: 10.1038/s42003-019-0357-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 02/05/2019] [Indexed: 12/18/2022] Open
Abstract
In every biological tissue, morphological and topological properties strongly affect its mechanical features and behaviour, so that ultrastructure, composition and mechanical parameters are intimately connected. Overall, it is their correct interplay that guarantees the tissue functionality. The development of experimental methods able to correlate these properties would open new opportunities both in the biological and the biomedical fields. Here, we report a correlative study intended to map supramolecular morphology, biochemical composition and viscoelastic parameters of collagen by all-optical microscopies. In particular, using human corneal tissue as a benchmark, we correlate Second-Harmonic Generation maps with mechanical and biochemical imaging obtained by Brillouin and Raman micro-spectroscopy. The study highlights how subtle variations in supramolecular organization originate the peculiar mechanical behavior of different subtypes of corneal lamellae. The presented methodology paves the way to the non-invasive assessment of tissue morpho-mechanics in biological as well as synthetic materials.
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Affiliation(s)
- Raffaella Mercatelli
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
| | - Sara Mattana
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- Department of Physics and Geology, University of Perugia, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Laura Capozzoli
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
- Center of Electron Microscopy “Laura Bonzi” (Ce.M.E), Institute of Chemistry of Organometallic Compounds, National Research Council (CNR-ICCOM), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Fulvio Ratto
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Francesca Rossi
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Roberto Pini
- Institute of Applied Physics “Nello Carrara”, National Research Council (CNR-IFAC), Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Daniele Fioretto
- Department of Physics and Geology, University of Perugia, Via Alessandro Pascoli, I-06123 Perugia, Italy
- CEMIN-Center of Excellence for Innovative Nanostructured Material, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Francesco Saverio Pavone
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- Department of Physics, University of Florence, Via Giovanni Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Silvia Caponi
- Institute of Materials, National Research Council (CNR-IOM), Unit of Perugia, c/o Department of Physics and Geology, University of Perugia, Via A. Pascoli, I-06123 Perugia, Italy
| | - Riccardo Cicchi
- National Institute of Optics, National Research Council (CNR-INO), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
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Wang T, Zhu L, Zhu J, Peng Y, Shen N, Yu Y, Yao M. Subacute effects of rose Bengal/Green light cross linking on rabbit thin corneal stability and safety. Lasers Surg Med 2017; 50:324-332. [PMID: 29095506 DOI: 10.1002/lsm.22762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Ti Wang
- Departmentof Ophthalmology; The 85th Hospital of PLA; Shanghai 200052 China
| | - Lu Zhu
- Department of Ophthalmology; Huadong Hospital Affiliated to Fudan University; Shanghai 200040 China
| | - Jingyin Zhu
- Department of Ophthalmology; Huadong Hospital Affiliated to Fudan University; Shanghai 200040 China
| | - Yinbo Peng
- Department of Plastic and Reconstructive Surgery, Shanghai 9th Hospital; JiaoTong University School of Medicine; Shanghai 201900 China
| | - Nianci Shen
- Department of Ophthalmology; Huadong Hospital Affiliated to Fudan University; Shanghai 200040 China
| | - Yan Yu
- RA consulting, 104 Aspen Court; Chalfont 18914 Pennsylvania
| | - Min Yao
- Department of Plastic and Reconstructive Surgery, Shanghai 9th Hospital; JiaoTong University School of Medicine; Shanghai 201900 China
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Wallerstein A, Adiguzel E, Gauvin M, Mohammad-Shahi N, Cohen M. Under-flap stromal bed CXL for early post-LASIK ectasia: a novel treatment technique. Clin Ophthalmol 2016; 11:1-8. [PMID: 28031696 PMCID: PMC5179218 DOI: 10.2147/opth.s118831] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Collagen cross-linking (CXL) for post-laser-assisted in situ keratomileusis (LASIK) ectasia (PLE) is traditionally performed either epi-on or epi-off on the corneal surface. This study describes a novel technique in treating early PLE with under-flap CXL (ufCXL) to the stromal bed and reports on 6-month outcomes. Patients and methods Case series of seven patients (eight eyes) with topography-diagnosed early PLE treated with ufCXL. Inclusion criteria were early, mild PLE defined as new-onset postoperative manifest refraction cylinder ≤1.50 D, with new topographic inferior steepening consistent with ectasia, uncorrected distance visual acuity (UDVA) of 20/40 or better, and corrected distance visual acuity (CDVA) of 20/25 or better. Existing LASIK flap was lifted, riboflavin was applied directly to the stromal bed, flap was repositioned, and 18 mW/cm2 ultraviolet light was applied for 3 minutes to the corneal surface. Post-ufCXL manifest refraction, UDVA and CDVA, corneal cylinder, Kmax, and corneal irregularity index were compared with pre-ufCXL measurements. Results Patients had a pre-ufCXL sphere of 0.09±0.48 D and cylinder of −0.78±0.49 D. At 6 months, post-ufCXL sphere (0.06±0.8 D; P=0.89) and cylinder (−1.09±0.76 D, P=0.26) were unchanged. Cumulative post-ufCXL UDVA was unchanged, achieving 20/20, 20/30, and 20/40 in 25%, 88%, and 88%, respectively, compared with 13%, 63%, and 88% pre-ufCXL (P=0.68). Post-ufCXL CDVA was unchanged (P=0.93) with a gain of one line in two eyes, a loss of one line in one eye, and five eyes unchanged. The efficacy index (P=0.76), safety index (P=0.89), Kmax (P=0.94), and corneal irregularity index (P=0.73) were also unchanged. Conclusion Preliminary results with ufCXL for early PLE are promising, demonstrating maintenance of visual accuracy, efficacy, safety, Kmax, and cylinder, with much quicker recovery times than surface CXL.
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Affiliation(s)
- Avi Wallerstein
- Department of Ophthalmology, Faculty of Medicine, McGill University; LASIK MD, Montreal
| | | | - Mathieu Gauvin
- Department of Ophthalmology, Faculty of Medicine, McGill University; LASIK MD, Montreal
| | | | - Mark Cohen
- LASIK MD, Montreal; Department of Surgery, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
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Marino GK, Torricelli AAM, Giacomin N, Santhiago MR, Espindola R, Netto MV. Accelerated Corneal Collagen Cross-linking for Postoperative LASIK Ectasia: Two-Year Outcomes. J Refract Surg 2015; 31:380-4. [PMID: 26046704 DOI: 10.3928/1081597x-20150521-04] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/15/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the effectiveness and safety of accelerated corneal collagen cross-linking for postoperative LASIK ectasia after 2 years. METHODS A prospective, single-center case series was performed with patients treated for postoperative LASIK ectasia. All eyes underwent accelerated corneal collagen cross-linking (CCL-Vario Crosslinking; Peschke Meditrade GmbH, Zurich, Switzerland) at 9 mW/cm(2) for 10 minutes. The main outcome measures were changes in uncorrected distance visual acuity, corrected distance visual acuity, central corneal thickness, corneal topography, and endothelial cell density. These parameters were assessed at baseline and at the 6-month and 1- and 2-year follow-up visit. RESULTS The study enrolled 40 eyes of 24 patients (15 male and 9 female) with a mean age of 33.8 ± 7.5 years (range: 24 to 52 years) that attained at least 2 years of follow-up. The surgical procedure was uneventful in all cases. All eyes stabilized after treatment without any further signs of progression and no statistically significant changes in the mean uncorrected distance visual acuity (P = .649), corrected distance visual acuity (P = .616), mean keratometry (P =.837), steep keratometry (P = .956), ultrasonic pachymetry (P = .135), slit-scanning pachymetry (P = .276), and endothelial cell density (P = .523). In addition, 72.5% of the patients presented stable or gains of Snellen lines over time. CONCLUSIONS Accelerated corneal collagen cross-linking seems to be safe and effective in halting postoperative LASIK ectasia progression after 2 years of follow-up. However, a longer follow-up period with a larger cohort is needed to validate these findings.
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A review of collagen cross-linking in cornea and sclera. J Ophthalmol 2015; 2015:289467. [PMID: 25922758 PMCID: PMC4398937 DOI: 10.1155/2015/289467] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/25/2015] [Indexed: 11/18/2022] Open
Abstract
Riboflavin/UVA cross-linking is a technique introduced in the past decades for the treatment of keratoconus, keratectasia, and infectious keratitis. Its efficacy and safety have been investigated with clinical and laboratory studies since its first clinical application by Wollensak for the treatment of keratoconus. Although its complications are encountered during clinical practice, such as infection inducing risk, minimal invasion merits a further investigation on its future application in clinical practice. Recently, collagen cross-linking in sclera shows a promising prospect. In present study, we summarized the representative studies describing the clinical and laboratory application of collagen cross-linking published in past decades and provided our opinion on the positive and negative results of cross-linking in the treatment of ophthalmic disorders.
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Rate of corneal collagen crosslinking redo in private practice: risk factors and safety. J Ophthalmol 2015; 2015:690961. [PMID: 25874118 PMCID: PMC4383466 DOI: 10.1155/2015/690961] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 09/20/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022] Open
Abstract
Objective. To report the rate of progression of keratectasia after primary crosslinking (CXL) and evaluate the safety and efficiency of CXL redo. Materials and Methods. We conducted a retrospective analysis of the patients who underwent CXL between 2010 and 2013 at the Beirut Eye Specialist Hospital, Lebanon. Progression of keratectasia was based on the presence of an increase in maximum keratometry of 1.00 D, a change in the map difference between two consecutive topographies of 1.00 D, a deterioration of visual acuity, or any change in the refraction. Primary and redo CXL were done using the same protocol. Results. Among the 221 eyes of 130 patients who underwent CXL, 7 eyes (3.17%) of five patients met the criteria of progression. All patients reported a history of allergic conjunctivitis and eye rubbing and progressed within 9 to 48 months. No complications were noted and all patients were stable 1 year after CXL redo. Conclusion. Allergic conjunctivitis and eye rubbing were the only risk factors associated with keratoconus progression after CXL. A close followup is thus mandatory, even years after the procedure. CXL redo seems to be a safe and efficient technique to halt the progression after a primary CXL.
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Abstract
PURPOSE OF REVIEW Treatment of hyperopia presents greater challenges than treatment of myopia for multiple reasons, including the fact that hyperopia tends to progress with age and becomes more symptomatic with the loss of accommodation. RECENT FINDINGS Despite these issues, surgeons have multiple options to treat hyperopia successfully. Modern laser vision correction has high success rates for most patients and performs acceptably in the presence of high hyperopia or high cylinder. Early studies combining excimer laser treatment with collagen cross-linking (CXL) suggest that this may improve refractive stability. Recent studies have also described femtosecond lenticule extraction and use of a solid-state laser in place of the excimer. In addition to cornea-based treatment, long-term studies of a hyperopic phakic intraocular lens have shown excellent visual outcomes and good safety. Cross-linking is increasingly being applied to the hyperopia that follows radial keratotomy. SUMMARY The established treatments for hyperopia continue to accumulate evidence supporting their safety and efficacy. The next step forward in treatment may arise from combining these treatments with CXL to stabilize the cornea long-term.
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Kymionis GD, Mikropoulos DG, Portaliou DM, Voudouragkaki IC, Kozobolis VP, Konstas AGP. An overview of corneal collagen cross-linking (CXL). Adv Ther 2013; 30:858-69. [PMID: 24170589 DOI: 10.1007/s12325-013-0065-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Indexed: 11/27/2022]
Abstract
Corneal collagen cross-linking (CXL) was first described over a decade ago and is now considered to be one of the most important surgical innovations of modern ophthalmology. Prior to its introduction, no interventions were available to arrest, or slow down ectatic disease progression, with corneal transplantation required in the majority of cases. Unlike earlier treatments of corneal ectasias that attempted to only improve the consequences of the disease, CXL aims to address the corneal biomechanical weakening itself. The long-term safety and efficacy of CXL have been established in several studies that have documented significant improvements in all outcome measures (visual acuity, spherical equivalent, astigmatism, and keratometric findings). The emerging combination of CXL with other interventions (termed 'CXL plus') optimizes the visual and topographic outcomes. This, along with the expansion of the techniques' indications for other clinical conditions, such as microbial keratitis, highlights the continuous improvement of the initial technique and confirms its wide acceptance. Overall, CXL has already demonstrated much promise and has several clinical indications, representing a clear example of recent advances in ocular therapy.
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Affiliation(s)
- George D Kymionis
- Faculty of Medicine, Institute of Vision and Optics, University of Crete, Heraklion, Greece
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