Cross-linking For Treatment Of Keratoconus Research Articles

A randomized clinical trial assessing theranostic-guided corneal cross-linking for treating keratoconus: the ARGO protocol

The Assessment of theranostic guided riboflavin/UV-A corneal cross-linking for treatment of keratoconus (ARGO; registration number NCT05457647) clinical trial tests the hypothesis that theranostic-guided riboflavin/UV-A corneal cross-linking (CXL) can provide predictable clinical efficacy for halting keratoconus progression, regardless of treatment protocol, i.e., either with or without epithelial removal. Theranostics is an emerging therapeutic paradigm of personalized and precision medicine that enables real-time monitoring of image-guided therapy. In this trial, the theranostic software module of a novel UV-A medical device will be validated in order to confirm its accuracy in estimating corneal cross-linking efficacy in real time. During CXL procedure, the theranostic UV-A medical device will provide the operator with an imaging biomarker, i.e., the theranostic score, which is calculated by non-invasive measurement of corneal riboflavin concentration and its UV-A light mediated photo-degradation. ARGO is a randomized multicenter clinical trial in patients aged between 18 and 40 years with progressive keratoconus aiming to validate the theranostic score by assessing the change of the maximum keratometry point value at 1-year postoperatively. A total of 50 participants will be stratified with allocation ratio 1:1 using a computer-generated stratification plan with blocks in two treatment protocols, such as epithelium-off or epithelium-on CXL. Following treatment, participants will be monitored for 12 months. Assessment of safety and performance of theranostic-guided corneal cross-linking treatment modality will be determined objectively by corneal tomography, corneal endothelial microscopy, visual acuity testing and slit-lamp eye examination.

Accelerated Corneal Crosslinking for Treatment of Keratoconus in Children and Adolescents under 18 Years of Age.

To evaluate the efficacy of accelerated (9 mW/cm2, 10 min) epithelium-off (epi-off) corneal crosslinking (A-CXL) in keratoconus (KC) patients < 18 years of age. Our retrospective study included 41eyes (25 male and 5 female patients, mean age 15.3 ± 1.2 years) who underwent A-CXL (9 mW/cm2, 10 min) because of progressive KC or critical KC at first presentation or asymmetrical finding in the partner eye. Outcome measures were best-corrected visual acuity (BCVA) and tomography readings (Pentacam HR, Oculus, Wetzlar, Germany), evaluated 2 years, 1 year, 6 months preoperatively, prior to surgery (pre-CXL) and 6 weeks, 6 months, 1 year, 2 years, > 2 years postoperatively (post-CXL). The demarcation line was assessed by anterior segment optical coherence tomography (SS-1000 and CASIA 2, Tomey, Nagoya, Japan). Total deviation value increased statistically significantly 6 months pre-CXL to pre-CXL. Anterior steep, flat, and mean keratometry values showed a statistically significant increase 6 weeks post-CXL (p < 0.05), followed by a significant decrease until 2 years post-CXL for steep and mean keratometry. Kmax increased 6 weeks post-CXL without statistical significance and decreased significantly even > 2 years post-CXL (p < 0.0001). Posterior keratometry as well as anterior and posterior astigmatism did not show any significant changes post-CXL. Thinnest and apical pachymetry decreased significantly until 6 months post-CXL (p < 0.05) and remained stable > 2 years post-CXL (p > 0.05). BCVA decreased 6 weeks post-CXL but improved significantly > 2 years post-CXL (p = 0.003). The demarcation line reached an average depth of 52.1%. Epi-off A-CXL stabilizes KC progression in patients < 18 years even > 2 years postoperatively and leads to a deep demarcation line. A "pseudoprogression" is observed up to the 6-week follow-up, which is not indicative of the long-term results.

Combined photorefractive keratectomy and corneal collagen cross-linking for treatment of keratoconus: a 2-year follow-up study.

Background:Corneal collagen cross-linking (CXL) is considered an effective procedure for slowing down or eliminating the progression of keratoconus. New techniques, in combination with CXL, have been proposed to stop the evolution of keratoconus and improve the visual function.Objective:To evaluate the effectiveness of combined photorefractive keratectomy (PRK) with mitomycin-C (MMC) application and CXL in the management of grade 1–2 keratoconus over a 2-year follow-up.Methods:Fifteen eyes underwent topography-guided PRK with 0.02% MMC application immediately followed by standard CXL.Results:Best corrected visual acuity improved from 0.15 ± 0.11 logMAR to 0.08 ± 0.09 logMAR at 24 months (p < 0.0001) in treated eyes. Mean steepest meridian keratometry reduced from 48.79 ± 3.22 D at baseline to 46.16 ± 3.11 D at 24 months (p < 0.0001). Mean flattest meridian keratometry reduced from 45.18 ± 2.17 D preoperatively to 44.35 ± 2.19 D at 24 months (p < 0.0001).Conclusion:Simultaneous topography-guided PRK with MMC 0.02% application and standard CXL is a safe, promising and effective procedure in the treatment of mild and moderate keratoconus.

One-Year Outcomes of Intracorneal Ring-Segment Insertion Assisted by Femtosecond Laser Simultaneously Performed with Corneal Collagen Cross-Linking for Treatment of Keratoconus.

PurposeTo assess the results of simultaneously performed femtosecond laser–assisted Keraring intrastromal corneal ring–segment insertion and corneal collagen cross-linking for the treatment of keratoconus.Patients and MethodsIn this retrospective, noncomparative, interventional study, 30 eyes of 24 progressive-keratoconus patients of both sexes aged 18–36 years old with poor best-corrected visual acuity (BCVA) and intolerance to contact lenses were included. All patients had been subjected to complete preoperative and postoperative ophthalmological examinations — unaided VA, BCVA, refraction, Pentacam, and contrast sensitivity examinations at 3-month, 6-month, and 1-year follow-ups.ResultsMean unaided VA had changed significantly from 0.649±0.239 logMAR preoperatively to 0.514±0.222 (P=0.014), 0.419±0.162 (P<0.001), and 0.379±0.142 (P<0.001) logMAR at the three follow-up visits, respectively. Mean BCVA had changed significantly from 0.326±0.144 logMAR preoperatively to 0.231±0.140 (P=0.006) at 1-year follow-up. Mean spherical equivalent refraction had decreased significantly at 6-month (P=0.0298) and 1-year follow-up (P=0.0081). Mean steep keratometry (K2) had also significantly reduced from 51.89±3.81 D to 49.87±4.57 D (P=0.034) at 6 months and 49.40±4.39 D (P=0.011) at 1 year. Mean refractive and keratometric astigmatism had significantly decreased at all follow-up visits.ConclusionAt 1-year follow-up, keraring intrastromal corneal ring–segment insertion assisted by femtosecond laser performed simultaneously with corneal collagen cross-linking resulted in an improvement in visual, refractive, and topographic outcomes, which may suggest it is an effective treatment of keratoconus.

Topography-guided corneal surface laser ablation combined with simultaneous accelerated corneal collagen cross-linking for treatment of keratoconus

Backgroundto study the outcomes of topography-guided customized excimer laser subepithelial ablation combined with accelerated CXL for progressive keratoconus.MethodsThirty-one eyes of 30 patients with progressive keratoconus were included in this prospective study. Topography-guided excimer laser ablation without refractive correction was performed. Simultaneous accelerated collagen cross-linking with ultraviolet light of 30 mW/cm2 for 4 min was followed. Uncorrected distance visual acuity (UCVA), manifest refraction, corrected distance visual acuity (CDVA), tomograghy were examined at postoperative 1, 6, and 12 months.ResultsUDVA improved slightly after surgery (P > 0.05). BSCDVA improved significantly from 0.32 ± 0.20 logMAR to 0.15 ± 0.14 logMAR at postoperative 12 months (P < 0.05). During 12-month follow-ups, there were no significant differences in manifest refraction and corneal keratometry except for maximal keratometry value of the anterior surface (Kapex), which decreased significantly from 57.23 ± 5.09D to 53.13 ± 4.47D (P < 0.05). Even though the thinnest corneal thickness decreased from 465 ± 24 μm to 414 ± 35 μm (P < 0.05), curvature asymmetry index front (SIf), keratoconus vertex front (KVf) and Baiocchi Calossi Versaci index front (BCVf) decreased significantly till postoperative 12 months (P < 0.05). Corneal higher-order aberrations and coma also decreased significantly till 12 months after surgery (P < 0.05).ConclusionsTopography-guided surface ablation without refractive correction combined with simultaneous accelerated collagen cross-linking provided good stability in refraction and corneal curvature, and also showed significant improvement in BSCDVA, corneal regularity and corneal optical quality.

Changes of corneal topography indices after corneal collagen crosslinking for treatment of keratoconus assessed by scheimpflug camera

Introduction Keratoconus is a bilateral, progressive ectasia of the cornea resulting in irregular astigmatism and myopia. We can use spectacles or contact lenses to correct the symptoms of keratoconus, whereas in advanced cases, corneal grafting is the only treatment. Corneal collagen cross-linking (CXL) is a promising treatment to strengthen and stabilize the cornea in cases of keratoconus. Aim To evaluate changes in corneal topography indices after corneal CXL in patients with keratoconus and analyze these changes. Patient and methods CXL was performed in eyes with keratoconus. Quantitative descriptors of corneal topography were measured with the Pentacam topographer and included seven indices: index of surface variance, index of vertical asymmetry, keratoconus index, central keratoconus index, minimum radius of curvature, index of height asymmetry, and index of height decentration. Follow-up was 6 months. Results The study comprised 50 eyes of 35 patients with keratoconus. In the entire patient cohort, there were significant improvements in the index of surface variance, index of vertical asymmetry, keratoconus index, and minimum radius of curvature at 6 months compared with baseline (all P Conclusion There were improvements in four of seven topography indices 6 months after CXL, suggesting an overall improvement in corneal shape.

A study to evaluate safety and efficacy of corneal collagen cross-linking with riboflavin in keratoconus patients

Introduction: Keratoconus is a disorder of progressive corneal steepening, resulting in cone shaped protrusion of cornea, corneal thinning, myopia and astigmatism. Objectives: To assess the efficacy and safety of corneal collagen cross-linking with Riboflavin in the management of keratoconus. Materials and Methods: The study was conducted at an eye hospital over a period of 22 months to evaluate utility of corneal collagen cross-linking in treatment of keratoconus. Study group included 10 eyes (6 right and 4 left) of 8 patients (6 males and 2 females) with one year follow-up. Results: Mean age of study population was 24.25 years (SD=5.97; SE=2.11). The mean logMAR UCVA prior to CXL was 0.85 which improved to 0.57 at 12 months. Mean baseline BCVA was 0.464 logMAR, this improved to 0.170 logMAR at 12 months. At baseline a mean SimK astigmatism was 4.99 (SD= 2.56) and this decrease to 4.72 at 12 months. Conclusion: Present study showed improved visual acuity (both UCVA and BSCVA), stable topographic parameters, stable visual acuity and stable endothelial cell counts over a period of 12 months follow up, indicating that corneal collagen cross-linking with riboflavin is a safe and effective treatment option for keratoconus. Keywords: Corneal collagen cross-linking and visual acuity, Keratoconus.

Corneal endothelial changes evaluation using specular microscope following collagen cross-linking in treatment of keratoconus

Objective The aim of this study was to evaluate the corneal endothelial changes following corneal collagen cross-linking treatment of keratoconus using a specular microscope.Patients and methods The study included 30 eyes of 30 patients with keratoconus, comprsing 16 males and 14 females, with a mean age of 28 years. Patients had a standard corneal collagen cross-linking after removal of the corneal epithelium. They were evaluated before and 1 month after the procedure using the specular microscope.Results The mean preoperative central corneal thickness of the patients was 477.5±35.57 µm, and at 1 month postoperatively, it was 477.9±36.88 µm, with no statistically significant change (P=0.7821). The mean preoperative value of cell density was 2963.1±364.1 cells/mm2 and became 2956.96±363 cells/mm2 1 month postoperatively, with no statistically significant change (P=0.7091). The mean preoperative coefficient of variation value was 36.3±5.9%, whereas 1 month postoperatively, it became 36.2±5.6%, with no statistically significant change (P=0.6951). The mean preoperative value of hexagonal cells was 49.93±7.9% and became 48.5±7.3% 1 month postoperatively, with no statistically significant change (P=0.2078).Conclusion There were no significant changes in human corneal endothelial parameters, as evaluated with the specular microscope, following cross-linking in keratoconic eyes.

Standard versus Accelerated Collagen Cross-Linking in Treatment of Keratoconus: Visual, Refractive, and Topographic Outcomes

Background: collagen cross-linking (CXL) is an effective, safe and rapidly progressive treatment modality for treatment of mild to moderate keratoconus not only in hindering the progression of the disease but also in improving the visual, refractive and topographic results. Objective: the study aims to compare the outcomes of standard and accelerated cross-linking in treatment of keratoconus. Patients and Methods: the present prospective study evaluated 99 eyes of 52 patients with keratoconus. They were classified into two groups; group (1) included 50 eyes (received standard CXL; 3Mw/cm2 , 30 min) (SCXL group) and group (2) 49 eyes (treated by accelerated CXL; 9Mw/cm2 , 10 min) (ACXL group). Spherical equivalent, uncorrected visual acuity, best-corrected visual acuity, and topographical analysis of the cornea were assessed at baseline and within 3 years postoperative. Simulated keratometry was measured in terms of Sim K-1, Sim K-2, K-max, cylindrical value, thickness of the cornea (at the thinnest point) and Q-value were evaluated. Results: postoperative uncorrected distance visual acuity and corrected distance visual acuity didn’t significantly changed in both groups. Postoperative spherical equivalent significantly decreased in standard CXL compared to accelerated CXL. Standard CXL had a greater effect in decreasing Simk-1, Simk-2, k-max and k-mean. K-max decreased from 52.33±5.55 to 50.35±5.14; P=0.07 and in accelerated group from 54.58±4.35 to 52.74±4.41; P=0.04. Also, postoperative corneal pachymetery (at thinnest location) was found to be more stable in standard CLX group. Conclusion: both standard and accelerated CXL are effective in early keratoconus management with better results in standard CXL procedure.

Standard versus Accelerated Collagen Cross-Linking in Treatment of Keratoconus: Visual, Refractive, and Topographic Outcomes

Background: collagen cross-linking (CXL) is an effective, safe and rapidly progressive treatment modality for treatment of mild to moderate keratoconus not only in hindering the progression of the disease but also in improving the visual, refractive and topographic results. Objective: the study aims to compare the outcomes of standard and accelerated cross-linking in treatment of keratoconus. Patients and Methods: the present prospective study evaluated 99 eyes of 52 patients with keratoconus. They were classified into two groups; group (1) included 50 eyes (received standard CXL; 3Mw/cm2 , 30 min) (SCXL group) and group (2) 49 eyes (treated by accelerated CXL; 9Mw/cm2 , 10 min) (ACXL group). Spherical equivalent, uncorrected visual acuity, best-corrected visual acuity, and topographical analysis of the cornea were assessed at baseline and within 3 years postoperative. Simulated keratometry was measured in terms of Sim K-1, Sim K-2, K-max, cylindrical value, thickness of the cornea (at the thinnest point) and Q-value were evaluated. Results: postoperative uncorrected distance visual acuity and corrected distance visual acuity didn’t significantly changed in both groups. Postoperative spherical equivalent significantly decreased in standard CXL compared to accelerated CXL. Standard CXL had a greater effect in decreasing Simk-1, Simk-2, k-max and k-mean. K-max decreased from 52.33±5.55 to 50.35±5.14; P=0.07 and in accelerated group from 54.58±4.35 to 52.74±4.41; P=0.04. Also, postoperative corneal pachymetery (at thinnest location) was found to be more stable in standard CLX group. Conclusion: both standard and accelerated CXL are effective in early keratoconus management with better results in standard CXL procedure.

Early epithelial complications of accelerated trans-epithelial corneal crosslinking in treatment of keratoconus: a case series.

To report a case series of early postoperative complications following combined accelerated corneal crosslinking (CXL) and trans-epithelial technique in keratoconus. Eleven eyes underwent accelerated trans-epithelial CXL (18mW/cm2 for 5min). Seven eyes (64%) developed complications in the first week postoperatively. Five eyes had large epithelial defects, and two eyes were complicated with diffuse punctate epithelial erosions. Early transient stromal haze was seen in eyes with epithelial complications. Anterior segment optical coherence tomography showed a faint demarcation line in six eyes (55%) with epithelial complications. A significant number of eyes developed epithelial complications shortly after combined accelerated trans-epithelial CXL, which defeated the benefits of leaving the epithelium intact.

Medium- to Long-Term Results of Corneal Cross-Linking for Keratoconus Using Phototherapeutic Keratectomy for Epithelial Removal and Partial Stromal Ablation.

To evaluate the medium- to long-term outcomes of corneal cross-linking in treatment of keratoconus using transepithelial phototherapeutic keratectomy (PTK-CXL) for epithelial removal and partial stromal ablation to stabilize the cornea, reduce corneal irregularity, and improve corrected vision. Retrospective analysis of 46 keratoconic eyes that underwent PTK-CXL. Corrected distance visual acuity (CDVA), manifest refraction, steep and flat simulated keratometry (Kmax and Kmin), corneal irregularity index (IRI), corneal higher order aberrations (HOAs), epithelial thickness profile, and corneal biomechanical characteristics were evaluated preoperatively and postoperatively. At a mean follow-up time of 21.0 ± 7.6 months (range: 10 to 43 months) postoperatively, CDVA improved from 0.25 ± 0.24 to 0.18 ± 0.22 logMAR (P = .002). CDVA remained unchanged in 32.6% (15 eyes) and 56.5% (26 eyes) gained up to five Snellen lines of CDVA, whereas 6.5% (3 eyes) lost two or more lines of CDVA, respectively. Postoperatively, flattening of Kmax from 50.58 ± 5.26 to 48.96 ± 4.00 diopters (D) and Kmin from 45.80 ± 3.11 to 44.77 ± 2.63 D (P < .001), reduction of IRI from 49.7 ± 24.5 to 43.4 ± 21.4 µm (P = .002), decrease of root mean square HOAs (at 5-mm diameter) from 2.66 ± 1.31 to 2.37 ± 1.37 µm (P = .037), and slight thickening of corneal epithelium were registered, whereas most of the corneal biomechanical measurements did not show statistically significant change. Two eyes demonstrated slight topographic regression. PTK-CXL seems to be effective in arresting the progression of keratoconus, improving CDVA, flattening the cornea, regularizing corneal surface, and reducing corneal HOAs. [J Refract Surg. 2017;33(7):488-495.].

Epithelial Thickness Profile Change After Combined Topography-Guided Transepithelial Photorefractive Keratectomy and Corneal Cross-linking in Treatment of Keratoconus.

To evaluate corneal epithelial remodeling after topography-guided transepithelial photorefractive keratectomy (PRK) combined with corneal collagen cross-linking (CXL) in the treatment of keratoconus. Retrospective analysis of the epithelial thickness distribution changes in 53 keratoconic eyes of 44 patients. Manifest refraction, maximum (Kmax) and minimum (Kmin) keratometry obtained by Placido topography, corneal irregularity index (IRI) measured by Scheimpflug topography, and the epithelial thickness profile over the central 5-mm zone obtained by anterior-segment spectral domain optical coherence tomography (SD-OCT) were evaluated preoperatively and at 1 to 3, 3 to 6, and more than 6 months postoperatively. Preoperatively, the epithelial thickness at the thinnest area (MinArea) was 48.8 ± 4.4 µm, correlating negatively with Kmax (r = -0.310, P < .05) and IRI (r = -0.362, P < .05). At more than 6 months postoperatively, epithelial thickening of 5.5 ± 5.1 µm occurred at the thinnest area (MinArea). There was no significant change in the epithelial thickness in other areas, resulting in a decrease of difference in epithelial thickness between MinArea and the rest of the paracentral areas of 5.5 ± 4.3 µm. Corrected distance visual acuity, refractive astigmatism, Kmax, Kmin, and IRI all improved after the treatment (P < .05). A significant epithelial thickness profile change occurred after the treatment due to an increase in thickness at the preoperatively thinnest area. Because the thickness in other areas remained largely unchanged, the treatment resulted in a more even epithelial thickness distribution. This may be attributed to regularized postoperative corneal stromal shape. [J Refract Surg. 2016;32(9):626-634.].

Efficacy of corneal collagen cross-linking for treatment of keratoconus: a meta-analysis of randomized controlled trials.

ObjectiveTo evaluate the efficacy of corneal collagen cross-linking (CXL) for the treatment of keratoconus.MethodsWe performed a literature search for randomized controlled trials that assessed the effect of CXL in slowing progression of keratoconus. The primary outcome measures included changes of topographic parameters, visual acuity, and refraction. Efficacy estimates were evaluated by weighted mean difference (WMD) and 95% confidence interval (CI) for absolute changes of the interested outcomes.ResultsSignificant decrease in mean keratometry value, maximum keratometry value and minimum keratometry value were demonstrated in the CXL group compared with the control group (WMD = -1.65; 95% CI: -2.51 to -0.80; P < 0.00001; WMD = -2.05; 95% CI: -3.10 to -1.00; P < 0.00001; WMD = -1.94; 95% CI: -2.63 to -1.26; P < 0.00001; respectively). Best spectacle-corrected visual acuity improved significantly in CXL group (WMD = -0.10; 95% CI: -0.15 to -0.05; P < 0.00001), whereas uncorrected visual acuity did not differ statistically. Manifest cylinder error decreased significantly in patients undergoing CXL procedure compared with control patients in sensitivity analysis (WMD = -0.388; 95% CI: -0.757 to -0. 019; P = 0.04). The changes in central corneal thickness and intraocular pressure were not statistically significant.ConclusionCXL may be an effective option in stabilizing keratoconus. Further long-term follow-up studies will be necessary to assess the persistence of CXL.

Comparison of epithelium-off and transepithelial corneal collagen cross-linking for treatment of keratoconus

Purpose The aim of the study was to assess the safety and efficacy of epithelium-off corneal cross-linking (conventional cross-linking) versus epithelium-on cross-linking (epithelium-on cross-linking) in the treatment of keratoconus. Patients and Methods This study was a nonrandomized comparative trial. Forty-three eyes of 35 patients were included in this study. All eyes were subjected to the preoperative and postoperative measures including uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA), pachymetry, simulated keratometry, and corneal topography. The preoperative and postoperative data were analyzed at baseline and at 3, 6, and 12 months in all eyes. The epithelium-off cross-linking group (the CXL group) included 25 eyes of 20 patients, whereas the epithelium-on cross-linking group (the transepithelial CXL group) included 18 eyes of 15 patients. The thinnest corneal thickness was at least 400 μm in all eyes. Results In the epithelium-off CXL group, there was a remarkable improvement regarding postoperative UCVA and BCVA (one line or more). Average K showed a marked reduction reaching more than 2 diopters. The mean astigmatism showed unremarkable changes. The main central corneal thickness showed very marked corneal thinning with reduction in the corneal thickness reaching more than 50 um in many cases. In the epithelium-on CXL group, there was unremarkable improvement regarding postoperative UCVA and BCVA. Average K showed almost no changes during the 12-month follow-up period. The mean astigmatism showed minimal changes. In addition, the main central corneal thickness showed considerable corneal thinning with reduction in the corneal thickness reaching up to 30 μm. Conclusion This study has proved that epithelium-on CXL is superior to epithelium-off CXL regarding pain, complications, and early patient convalescence. However, epithelium-off CXL is superior to epithelium-on CXL regarding the efficacy in visual stabilization and improvement. In short, this study concluded that conventional epithelium-off CXL is better than epithelium-on CXL.

Comparison of Epithelium-Off and Transepithelial Corneal Collagen Cross-linking for Treatment of Keratoconus

Purpose The aim of the study was to assess the safety and efficacy of epithelium-off corneal cross-linking (conventional cross-linking) versus epithelium-on cross-linking (epithelium-on cross-linking) in the treatment of keratoconus. Patients and Methods This study was a nonrandomized comparative trial. Forty-three eyes of 35 patients were included in this study. All eyes were subjected to the preoperative and postoperative measures including uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA), pachymetry, simulated keratometry, and corneal topography. The preoperative and postoperative data were analyzed at baseline and at 3, 6, and 12 months in all eyes. The epithelium-off cross-linking group (the CXL group) included 25 eyes of 20 patients, whereas the epithelium-on cross-linking group (the transepithelial CXL group) included 18 eyes of 15 patients. The thinnest corneal thickness was at least 400 μm in all eyes. Results In the epithelium-off CXL group, there was a remarkable improvement regarding postoperative UCVA and BCVA (one line or more). Average K showed a marked reduction reaching more than 2 diopters. The mean astigmatism showed unremarkable changes. The main central corneal thickness showed very marked corneal thinning with reduction in the corneal thickness reaching more than 50 um in many cases. In the epithelium-on CXL group, there was unremarkable improvement regarding postoperative UCVA and BCVA. Average K showed almost no changes during the 12-month follow-up period. The mean astigmatism showed minimal changes. In addition, the main central corneal thickness showed considerable corneal thinning with reduction in the corneal thickness reaching up to 30 μm. Conclusion This study has proved that epithelium-on CXL is superior to epithelium-off CXL regarding pain, complications, and early patient convalescence. However, epithelium-off CXL is superior to epithelium-on CXL regarding the efficacy in visual stabilization and improvement. In short, this study concluded that conventional epithelium-off CXL is better than epithelium-on CXL.