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Purpose: To evaluate the effect of conventional and accelerated corneal crosslinking (CXL) on visual acuity, corneal topography, corneal epithelial thickness, and subbasal nerve morphology in progressive keratoconus patients., Methods: In this prospective and randomized study, twenty eyes of 20 patients were treated with conventional CXL (3 mW/cm 2 , 30 min, C-CXL) and 19 eyes of 19 patients were treated with accelerated CXL (9 mW/cm 2 , 10 min, A-CXL). The spherical equivalent, uncorrected visual acuity, best-corrected visual acuity, keratometric measurements, demarcation line measurement and epithelial thickness mapping analyses, and subbasal nerve morphology with in vivo confocal microscopy (IVCCM) were evaluated at baseline and at postoperative months 1, 3 and 6., Results: At postoperative 6 months, a significant improvement was observed in all keratometric values in both treatment groups (p < 0.05). All epithelial thickness indices, except central, temporal, and inferotemporal thickness, were reduced at 1 month postoperatively in both treatment groups. The epithelial map uniformity indices (standard deviation and difference between min-max thickness) were significantly lower than the baseline values at all time points after CXL in both treatment groups (p < 0.001). Compared with the preoperative values, there was a significant decrease in all IVCCM parameters at 1 month postoperatively (p < 0.05). At 6 months postoperatively, corneal nerve fiber density and corneal nerve branch density recovered to preoperative values in the A-CXL group, whereas corneal nerve regeneration was not complete in the C-CXL group., Conclusion: Both conventional and accelerated CXL treatments appear to be effective in halting the progression of KC. Corneal epithelial irregularity slightly improves after CXL. The regeneration of subbasal nerves is faster after A-CXL treatment., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Purpose: To compare the efficacy and safety of accelerated corneal cross-linking (CXL) with conventional CXL in pediatric patients with keratoconus., Methods: Consecutive patients with keratoconus received either accelerated CXL (9 mW/cm 2 irradiance for 10 minutes) or conventional CXL (3 mW/cm 2 irradiance) for 30 minutes. Visual acuities (uncorrected [UDVA] and corrected [CDVA] distance visual acuity, logMAR), spherical error, cylindrical error, spherical equivalent, and keratometric values were recorded. Follow-up measurements were compared with baseline values., Results: The study enrolled 48 eyes: 22 eyes had accelerated CXL (mean age: 16.0 ± 1.7 years) and 26 eyes had conventional CXL (mean age: 15.7 ± 1.6 years). Compared with preoperative values, all mean keratometric values significantly improved in the accelerated CXL group (flat [K1]: Δ = -0.64 D, P < .0001, steep [K2]: Δ = -0.63 D, P = .009 and Kmax: Δ = -0.55 D, P = .028), but no significant changes were observed in the mean UDVA and CDVA. In the conventional CXL group, all mean keratometric values and CDVA significantly improved (K1: Δ = -0.65 D, P = .017, K2: Δ = -0.87 D, P = .006, Kmax: Δ = -1.47 D, P = .011). No significant changes were observed in refractive error in either CXL group. There were no significant differences in the keratometric readings, visual acuities, or refractive error between the two groups at the 2-year follow-up., Conclusions: Both conventional and accelerated CXL protocols appear to be effective in stabilizing keratoconus progression in pediatric patients. Improved CDVA was also observed in the conventional CXL group. Accelerated CXL, with its advantage of shorter treatment duration, may be an alternative in pediatric patients. [J Refract Surg. 2020;36(4):265-269.]., (Copyright 2020, SLACK Incorporated.)

Purpose: To evaluate the effectiveness of repeated corneal collagen cross-linking (CXL) in eyes with progressive keratoconus after primary CXL., Methods: Twelve eyes of 10 patients who underwent repeated CXL were included in this study. All cases were treated with a second CXL when disease progression was noted. Uncorrected visual acuity, best-corrected distance visual acuity, and corneal tomography were performed before and after repeated CXL. Common risk factors for progression were recorded., Results: The mean age of the patients was 23.4 ± 6.2 (14-34) years. Eye rubbing was detected in 6 patients. The preoperative maximum keratometry (Kmax) value was >58.0 diopters (D) in 11 eyes (62.2 ± 4.9 D). Repeated CXL was performed with a mean interval of 19.3 months after the first CXL procedure when a disease progression of 2.3 D on average in Kmax was determined. With a mean follow-up of 36 months, Kmax regressed in 8 eyes, remained stable in 2 eyes, and progressed in 2 eyes after repeated CXL. Uncorrected and corrected visual acuity remained unchanged. No complications were observed., Conclusions: Repeated CXL seems to be effective in stabilizing keratoconus progression after failure of primary CXL. Patients should be followed up at least for 2 years after primary CXL.

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.

Purpose: To evaluate the efficacy of different accelerated corneal crosslinking (CXL) treatment protocols in patients with progressive keratoconus., Setting: Marmara University School of Medicine, Istanbul, Turkey., Design: Retrospective case series., Methods: Patients with progressive keratoconus had 9 mW accelerated CXL (10 minutes; 9 mW/cm 2 ), 30 mW continuous-light accelerated CXL (4 minutes; 30 mW/cm 2 ), or 30 mW pulsed-light accelerated CXL (8 minutes [1 second on/1 second off]; 30 mW/cm 2 )., Results: Of 134 eyes, 34 eyes had conventional CXL, 45 had 9 mW accelerated CXL, 28 had 30 mW continuous-light accelerated CXL (4 minutes, 30 mW/cm 2 ), and 27 eyes had 30 mW pulsed-light accelerated CXL. The uncorrected (UDVA) (P < .001 both) and corrected (CDVA) distance visual acuities increased in with conventional CXL and 9 mW accelerated CXL (P = .001 and P = .002, respectively). With 30 mW continuous accelerated CXL, only CDVA improved (P = .019). With 30 mW pulsed accelerated CXL, UDVA and CDVA did not change significantly (P > .05). With conventional CXL and 9 mW accelerated CXL, all keratometric (K) readings (K1, K2, mean K, maximum K) improved significantly (conventional CXL: P = .014, P = .002, P = .008, and P < .001, respectively; 9 mW accelerated CXL: all P < .001). With 30 mW, no K values changed significantly compared with baseline (all groups P > .05)., Conclusion: Although 30 mW accelerated CXL treatment modalities appeared to be effective in stabilizing keratoconus progression, they seemed less effective in achieving topographic improvement., (Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate the efficacy of riboflavin/ultraviolet A epithelium-off (epi-off) and epithelium-on (epi-on) corneal collagen cross-linking (CXL) in progressive pediatric keratoconus., Methods: Thirty-six eyes of 27 patients aged 18 years or younger (12-18 years) diagnosed with progressive keratoconus and treated with epi-off (n=18 eyes) or epi-on (n=18 eyes) CXL were included in this study. All patients were followed up for 24 months postoperatively., Results: At 24-month follow-up, the mean corrected distance visual acuity (CDVA) improved from 0.24±0.17 to 0.17±0.11 logMAR in the epi-off group (P=0.032). In the epi-on group, CDVA improved from 0.33±0.23 to 0.26±0.20 logMAR (P=0.012), but the improvement was not significantly different between groups (P>0.05). In the epi-off group, all mean K values improved: K1 (Δ=-0.63 D, P=0.024), K2 (Δ=-0.73 D, P=0.008), and Kmax (Δ=-1.4 D, P=0.035), whereas in the epi-on group, Kmax and K2 did not change significantly and K1 (Δ=0.68 D, P=0.029) significantly worsened. Postoperative mild corneal haze occurred in 5 eyes (28%) in the epi-off group. No postoperative complications were observed in the epi-on group. In 94.4% of the epi-off group, keratoconus regressed (44.4%) or stabilized (50.0%), whereas in the epi-on group, only 66.6% regressed (33.3%) or stabilized (33.3%), and the difference was significant (P=0.038)., Conclusions: The efficacy of the epi-on procedure in terms of its ability to halt keratoconus progression appears to be 0.70 of the efficacy of epi-off CXL.

Purpose: To compare the efficacy of epithelium-off corneal collagen crosslinking (CXL) with transepithelial CXL in patients with progressive keratoconus., Setting: Department of Ophthalmology, Marmara University School of Medicine, Istanbul, Turkey., Design: Retrospective cohort study., Methods: Eyes that had transepithelial CXL were compared with eyes treated with epithelium-off CXL. All patients with a follow-up of 18 months were evaluated for uncorrected (UDVA) and corrected (CDVA) distance visual acuities, corneal topography, aberrometry, and pachymetry (Pentacam)., Results: The mean patient age was 22.8 years ± 4.7 (SD) (range 18 to 31 years) in the transepithelial group (30 eyes) and 23.7 ± 3.9 years (range 18 to 30 years) in the epithelium-off group (30 eyes). The mean UDVA and CDVA significantly improved in both groups (P < .001). There was no significant difference in the CDVA gain between the 2 groups. In the epithelium-off group, significant improvements occurred in spherical error (P = .002), spherical equivalent (P = .004), maximum keratometry (K), flat K (P = .036), and steep K (P < .001). The reductions in flat K, steep K, and maximum K were greater in the epithelium-off group (P = .004 for flat K; P < .001 for steep K and maximum K). In the transepithelial group, significant improvements occurred in the cylindrical error (P = .009) and in the index of surface variance and index of surface asymmetry (both P < .001)., Conclusion: Although transepithelial CXL seemed to have reduced effectiveness in inducing improvement in topographic indices, its effect on visual acuity is likely to be similar to that of epithelium-off CXL., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned., (Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)