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Purpose: To assess 3-year safety and efficacy of enhanced-fluence pulsed-light iontophoresis cross-linking (EF I-CXL) in patients with progressive keratoconus., Methods: This prospective interventional pilot study included 24 eyes of 20 patients, with a mean age of 23.9 years (range: 15 to 36 years). Iontophoresis with riboflavin solution was used for stromal imbibition. The treatment energy was optimized at 30% (7 J/cm 2 ) and ultraviolet-A power set at 18 mW/cm 2 × 6.28 minutes of pulsed-light on-off exposure, with a total irradiation time of 12.56 minutes. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), corneal tomography, and corneal optical coherence tomography (OCT) at baseline and 1, 3, 6, 12, 24, and 3 years postoperatively were evaluated., Results: At 3 years, average UDVA decreased from 0.50 ± 0.10 to 0.36 ± 0.08 logMAR (P < .05), average maximum keratometry decreased from 52.94 ± 1.34 to 51.4 ± 1.49 diopters (D) (Delta: -1.40 ± 0.80 D; P < .05), average coma improved from 0.24 ± 0.05 to 0.12 ± 0.02 µm (P = .001), and symmetry index decreased from 4.22 ± 1.01 to 3.53 ± 0.90 D. Corneal OCT showed demarcation line detection at 285.8 ± 20.2 µm average depth in more than 80% at 1 month postoperatively., Conclusions: The 3-year results of EF I-CXL showed satisfactory I-CXL functional outcomes, increasing the visibility and the depth of demarcation line closer to epithelium-off standard CXL. [J Refract Surg. 2020;36(5):286-292.]., (Copyright 2020, SLACK Incorporated.)

The objective of this non-randomized trial was comparison of two-year changes in dynamic corneal response (DCR) between 18 mW/cm 2 (5- min) and 9 mW/cm 2 (10-min) cross-linking (CXL) protocols, using novel stiffness parameters and correlating them to clinical indices. The two groups were evaluated before and 2 years after the procedure using Corvis ST (Oculus Optikgeräte GmbH, Germany) and DCR parameters such as deformation amplitude ratio at 1 mm and 2 mm (DA ratio-1 mm and DA ratio-2 mm) and integrated radius and stiffness parameters at A1 (SP-A1). Two-year follow-up was completed for 16 of the 30 eyes in the 5-min group and 21 of the 25 eyes in the 10-min group; data from those who were lost to follow-up was not included in the analyses. Mean age at baseline was 21.7 ± 4.9 and 21.5 ± 5.2 years in the 5- and 10-min groups, respectively (P = 0.895). At 2 years after CXL, in the 5-min group, the reduction in integrated radius (-1.12 ± 1.27 mm, P = 0.003) was significant, and the increase in SP-A1 (7.11 ± 14.86 mmHg/mm, P = 0.075) was borderline, while in the 10-min group, the decrease in DA ratio-2 mm (-0.43 ± 0.58, P = 0.003) and integrated radius (-1.89 ± 1.72 mm, P < 0.001), and increase in SP-A1 (7.67 ± 10.92 mmHg/mm, P = 0.004) were significant. In both groups, the strongest and significant correlation was observed between DCR parameters and changes in radius of curvature. In conclusion, results indicated corneal strengthening with both protocols especially with the 9 mW/cm 2 . Corvis ST indices can provide "in vivo" biomechanical evidence on the efficacy of CXL that may occur prior to clinical indices., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: To compare the 2-year follow-up outcomes of three groups of patients with keratoconus treated with transepithelial iontophoresis (I-CXL), iontophoresis with epithelial removal (I-SCXL), and standard epithelium-off (S-CXL) CXL for progressive keratoconus., Methods: Sixty eyes of 60 patients treated with CXL for progressive keratoconus were included in this comparative, prospective clinical study. Twenty patients were included in each group (I-CXL, I-SCXL, and S-CXL). Corrected distance visual acuity (CDVA), refraction, corneal topography, Scheimpflug tomography, and aberrometry were assessed at baseline and at 1, 3, 6, 12, and 24 months of follow-up. To assess the long-term safety and efficacy of these treatments, the preoperative values were compared with the values at 24 months of follow-up., Results: The main outcome of the study was the non-statistically significant difference between the three protocols in induced change in most of the parameters, including visual acuity (P = .665), topographic indexes (all P > .05), and maximum keratometry (P = .611) after 2 years of follow-up. There were no significant differences in the change in refractive error following CXL in all groups or between groups (all P > .05). Conversely, I-CXL induced significantly less corneal thinning (P = .0299 and .0121) and a significantly greater reduction of higher order aberrations and coma (all P < .0001) compared to S-CXL and I-SCXL. All protocols induced a significant increase in visual acuity (S-CXL P = .0004, I-SCXL P = .0045, and I-CXL P = .004)., Conclusions: The 2-year results of this comparative, prospective clinical study demonstrate the efficacy and safety of I-CXL to treat progressive keratoconus and overcome the limitations of CXL with epithelial debridement. [J Refract Surg. 2019;35(3):184-190.]., (Copyright 2019, SLACK Incorporated.)

Purpose: To evaluate the impact of varying treatment time on the efficacy of iontophoresis-assisted transepithelial corneal cross-linking (I-CXL) in ex vivo porcine corneas., Methods: One hundred twelve porcine corneas with intact epithelium were divided into 7 groups and analyzed. Groups 1, 2, and 3 received standard epitheliumoff CXL (S-CXL) with hypo-osmolaric 0.1% riboflavin and 30 minutes of ultraviolet-A (UV-A) irradiation at 3 mW/cm 2 , 10 minutes at 9 mW/cm 2 , or were not irradiated (controls). Groups 4, 5, 6, and 7 received I-CXL for either 60 minutes at 1.5 mW/cm 2 , 30 minutes at 3 mW/cm 2 , 10 minutes at 9 mW/cm 2 , or were not irradiated (controls). Elastic modulus and stress after relaxation of 5-mm wide corneal strips were analyzed., Results: In the S-CXL groups, significant differences (P ≤ .05) in stress-strain extensometry were found between controls and 3 mW/cm 2 for 30 minutes (group 1) and between controls and 9 mW/cm 2 for 10 minutes (group 2). In the I-CXL groups, only the 1.5 mW/cm 2 for 60 minutes setting (group 4) showed a significant stiffening effect. All epithelium-off groups provided a stiffening effect significantly stronger than I-CXL: with a stiffening effect of 149% and 112%, groups 1 and 4 were the groups with greater elastic modulus between the S-CXL and I-CXL groups, respectively., Conclusions: The biomechanical effect of I-CXL increased significantly when using a low irradiance/long irradiation setting. Oxygen diffusion thus represents a limiting factor even when riboflavin penetration is improved via iontophoresis. Still less effective than S-CXL, this modification may help establish transepithelial CXL as a treatment option in selected cases. [J Refract Surg. 2018;34(11):768-774.]., (Copyright 2018, SLACK Incorporated.)

Purpose: To assess the safety and efficacy of a novel pulsed-light enhanced-fluence iontophoresis corneal cross-linking (EF I-CXL) procedure in patients with progressive keratoconus., Methods: This prospective interventional pilot study included 12 eyes of 10 patients. Iontophoresis with Ricrolin+ solution (Sooft, Montegiorgio, Italy) was used for stromal imbibition. The treatment energy dose (fluence) was optimized at 30% (from 5.4 J to 7 J/cm 2 ) and ultraviolet-A (UV-A) power set at 18 mW/cm 2 × 6.28 minutes of exposure time, pulsing the light 1 second on/1 second off with a total irradiation time of 12.56 minutes. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), Scheimpflug corneal tomography data, and corneal optical coherence tomography (OCT) at baseline and 1, 3, 6, and 12 months postoperatively were evaluated., Results: Twelve-month statistically significant average data (P < .05) showed UDVA decreased from 0.50 ± 0.10 to 0.36 ± 0.08 logMAR, maximum keratometry decreased from 52.86 ± 1.50 to 51.49 ± 0.90 diopters (D), surface asymmetry index decreased from 2.34 ± 0.36 to 2.13 ± 1.12 D, symmetry index decreased from 4.22 ± 1.01 to 3.56 ± 0.90 D, and coma decreased from 0.25 ± 0.05 to 0.14 ± 0.06 μm. Corneal OCT showed greater than 80% demarcation line detection at 295.8 ± 20.2 μm depth on average in the first postoperative month., Conclusions: The preliminary results of the EF I-CXL protocol demonstrate its capability to increase I-CXL efficacy closer to standard CXL. [J Refract Surg. 2018;34(7):438-444.]., (Copyright 2018, SLACK Incorporated.)

Purpose: To assess topographical changes in patients with keratoconus while awaiting corneal cross-linking (CXL) treatment., Methods: In this prospective, double-center, observational clinical study, patients with keratoconus were enrolled. Progression was defined as a change in the curvature within the cone area of at least 1.00 diopter (D) on tangential map and a thinning of 20 μm at the thinnest point after measurements taken at least 3 months apart. Morphological parameters were assessed at baseline (day of listing for CXL) and on the day of CXL treatment, including slit-lamp biomicroscopy, keratometry (maximum, minimum, and mean), and thinnest corneal thickness using corneal tomography (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany)., Results: One hundred four eyes of 104 patients were included. The waiting time was 84.8 ± 62.9 days. Twenty-five percent of patients showed evidence of progression while waiting for treatment. Patients who progressed while waiting for treatment were younger (22.2 ± 6.79 years) compared to those who did not show evidence of progression (25.4 ± 5.62 years) (P = .02). Stratification by age groups showed a significant worsening of maximum keratometry of 1.18 ± 1.37 D in patients younger than 18 years compared to those 18 to 26 years of age and those older than 26 years (P = .002 and .042, respectively). The multivariate model confirmed that the progression steepening of the maximum keratometry while waiting for treatment was associated with age (P = .028)., Conclusions: The results suggest that stratification of waiting time according to the patient's age is required to reduce the risk of further progression of keratoconus. [J Refract Surg. 2018;34(3):177-180.]., (Copyright 2018, SLACK Incorporated.)

Purpose: To compare 1-year transepithelial corneal collagen cross-linking with iontophoresis (I-CXL) outcomes with standard CXL (S-CXL) epithelium-off for progressive keratoconus., Methods: Forty eyes of 40 patients with progressive keratoconus were included in this comparative, prospective clinical study. Corrected distance visual acuity (CDVA), spherical equivalent, cylinder refraction, corneal topography, Scheimpflug tomography, aberrometry, and endothelial cell count were assessed at baseline and at 1, 3, 6, and 12 months of follow-up., Results: Patients received either I-CXL (20 eyes) or S-CXL (20 eyes). Functional parameters (visual acuity and aberrometry) showed a significant improvement (P < .05) after 6 and 12 months of follow-up in both groups. In the I-CXL group, the CDVA showed a rapid recovery of vision after 3 months (P = .01) compared to baseline. Morphological parameters showed a significant reduction of maximum keratometry in the S-CXL group by -1.05 ± 1.51 diopters (D) after 12 months, whereas the I-CXL group curvature was stable (-0.31 ± 1.87 D). Minimum pachymetry values were stable even after 12 months of follow-up in the I-CXL group, whereas a significant corneal thinning 12 months following treatment was recorded in the S-CXL group (P < .001). None of the patients had continuous progression of keratoconus or had to repeat CXL procedures. Endothelial cell counts did not change significantly (P > .05)., Conclusions: The 1-year outcomes suggest that I-CXL might be comparable to S-CXL in stabilizing the progression of the degenerative ectatic disease. Additionally, quicker improvement of functional parameters was reported in the I-CXL group. [J Refract Surg. 2016;32(10):672-678.]., (Copyright 2016, SLACK Incorporated.)

Purpose: To report initial clinical results of transepithelial corneal collagen cross-linking with iontophoresis (I-CXL)., Methods: Twenty eyes of 20 patients diagnosed as having progressive keratoconus who underwent I-CXL were included in this prospective non-randomized clinical study. Corrected distance visual acuity (CDVA), spherical equivalent and cylinder refraction, various corneal topography and Scheimpflug tomography parameters, aberrometry, anterior segment optical coherence tomography, and endothelial cell count were assessed at baseline and at 1, 3, 6, and 12 months postoperatively., Results: CDVA improved significantly at 3, 6, and 12 months postoperatively (logMAR difference of -0.07 ± 0.01, -0.09 ± 0.03, and -0.12 ± 0.06, respectively; P < .05). Aberrometry remained stable during follow-up and a trend toward improvement was noted. All topographic parameters (including maximum keratometry) were stable during the follow-up, but exhibited a positive non-significant trend toward improvement. Minimum corneal thickness values were stable for up to 12 months postoperatively. None of the patients showed a progression of keratoconus. Endothelial cell counts did not change significantly (P > .05)., Conclusions: Preliminary results up to 1 year postoperatively indicate the efficacy of I-CXL in stabilizing the progression of this degenerative disease combined with significant improvement of CDVA. I-CXL, which spares the corneal epithelium, has the potential to become a valid alternative for halting the progression of keratoconus while reducing postoperative patient pain, risk of infection, and treatment time in select patients; however, the relative efficacy of this technique compared to standard epithelium-off techniques remains to be determined., (Copyright 2014, SLACK Incorporated.)

Purpose: To compare biomechanical effect, riboflavin penetration and distribution in transepithelial corneal collagen cross-linking with iontophoresis (I-CXL), with standard cross linking (S-CXL) and current transepithelial protocol (TE-CXL)., Materials and Methods: The study was divided into two different sections, considering, respectively, rabbit and human cadaver corneas. In both sections corneas were divided according to imbibition protocols and irradiation power. Imaging mass spectrometry by matrix-assisted laser desorption/ionization (MALDI-IMS) and stress-strain measurements were used. Forty-eight rabbit and twelve human cadaver corneas were evaluated., Results: MALDI-IMS showed a deep riboflavin penetration throughout the corneal layers with I-CXL, with a roughly lower concentration in the deepest layers when compared to S-CXL, whereas with TE-CXL penetration was considerably less. In rabbits, there was a significant increase (by 71.9% and P = 0.05) in corneal rigidity after I-CXL, when compared to controls. In humans, corneal rigidity increase was not significantly different among the subgroups., Conclusions: In rabbits, I-CXL induced a significant increase in corneal stiffness as well as better riboflavin penetration when compared to controls and TE-CXL but not to S-CXL. Stress-strain in human corneas did not show significant differences among techniques, possibly because of the small sample size of groups. In conclusion, I-CXL could be a valid alternative to S-CXL for riboflavin delivery in CXL, preserving the epithelium.

Purpose: To report the 4-year outcomes of corneal cross-linking (CXL) for progressive keratoconus in a population of different age groups., Design: Retrospective, single-center, nonrandomized clinical study., Participants: Four hundred consecutive eyes treated with corneal CXL for progressive keratoconus from April 2006 through April 2010., Intervention: After removal of the epithelium, the cornea was irrigated for 30 minutes with a solution of 0.1% riboflavin and 20% dextran, followed by irradiation with an ultraviolet A light of 3 mW/cm(2) for 30 minutes., Main Outcome Measures: Best-corrected visual acuity (BCVA), sphere and cylinder refraction, corneal topography, Scheimpflug tomography, and aberrometry were assessed at baseline and at 1, 6, 12, 24, 36, and 48 months after corneal CXL treatment. The compiled data were stratified according to age (group A, younger than 18 years; group B, 18-29 years; group C, 30-39 years; and group D, older than 40 years)., Results: Comparative analysis included 400 eyes of 301 patients. Functional results showed a significant increase in BCVA in group A by a mean reduction of -0.11 logarithm of the minimum angle of resolution (logMAR) after 12 months, in group B by a mean reduction of -0.31 logMAR after 36 months, in group C by a mean reduction of -0.33 logMAR after 36 months, and in group D by a mean reduction of -0.26 logMAR after 36 months. Morphologic results showed an analogous regularization of corneal shape with a significant reduction of opposite sector index by a mean value of -0.53 at 12 months in group A, -1.14 at 36 months in group B, -1.10 at 36 months in group C, and -0.55 at 12 months for group D. Optical quality improvement was demonstrated by a mean significant reduction of coma -1.52 μm after 12 months in group A, -1.58 μm after 24 months in group B, -2.57 μm after 36 months for group C, and -0.25 μm after 36 months in group D., Conclusions: Outcomes stratified by age indicate the efficacy of corneal CXL in stabilizing the progression of ectatic disease in all age groups and improving the functional and morphologic parameters in select groups. Results indicated better functional and morphologic results in the population between 18 and 39 years of age., Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the safety and efficacy of treatment of severe infectious corneal ulcers with hypoosmolar riboflavin solution and UV-A collagen cross-linking (CXL) without deepithelizing the cornea., Methods: Four eyes of 3 patients with severe keratitis and associated corneal melting, were treated with a new protocol of corneal CXL for infectious keratitis, named cross-linking window absorption (CXL-WA). CXL-WA was performed when the infection did not respond to systemic and topical antibiotic therapy. The protocol entails the use of hypoosmolar riboflavin before the irradiation with UV-A, and the penetration is obtained through the epithelial defect overlying the ulcer., Results: In all cases, CXL halted the progression of the ulcer. After a minimum follow-up of 3 months, none of the patients had recurrence of the infection., Conclusion: CXL-WA is a promising technique of treatment of infectious corneal ulcers, delaying or preventing more invasive approaches.

Purpose: To report refractive, topographic, aberrometric, and tomographic outcomes 24 months after corneal cross-linking (CXL) in patients up to 18 years of age with progressive keratoconus., Design: Prospective, interventional case series., Methods: Forty eyes underwent riboflavin-ultraviolet A-induced CXL. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), sphere and cylinder, topography, aberrometry, tomography, and endothelial cell counts were evaluated at baseline and at 1, 3, 6, 12, and 24 months., Results: Mean logarithm of the minimum angle of resolution baseline UCVA and BSCVA were 0.79 ± 0.21 and 0.39 ± 0.10, respectively. Mean UCVA and BSCVA at 2 years were 0.58 ± 0.18 and 0.20 ± 0.09, respectively. The improvement in UCVA and BSCVA was significant throughout the postoperative follow-up (P < .05). Mean spherical equivalent refraction showed a significant decrease of 1.57 diopters (D) at 24 months (P = .02). Mean baseline simulated keratometry was 46.32 D in the flattest meridian and 51.48 D in the steepest meridian; at 2 years, the values were 45.30 D (P = .04) and 50.21 D (P = .07), respectively. For a 3-mm pupil, there was a significant reduction (P < .05) in whole eye (total), corneal, higher-order, and astigmatic wavefront aberrations at 24 months. A significant difference (P < .05) in total coma and total spherical aberration 2 years after CXL also was observed. Mean baseline pupil center pachymetry decreased significantly (P = .04) at 6 months, but recovered by 12 months and remained stable thereafter through the 2-year follow-up. Endothelial cell counts did not change significantly (P = .32)., Conclusions: CXL improved UCVA and BSCVA in the study patients, most likely by significantly reducing corneal asymmetry and corneal as well as total wavefront aberrations., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: To report a case of bilateral, ring-shaped, intrastromal corneal opacities after corneal cross-linking (CXL) for progressive keratoconus., Methods: A 21-year-old man with bilateral, progressive keratoconus underwent CXL with riboflavin 0.1% and ultraviolet A (UVA) light in the right eye and, 6 months later, in the left eye., Results: One day after CXL, the right eye showed a sharply demarcated white ring in the corneal periphery. The ring involved the superficial stroma at 2 mm from the limbus, extended from 1 to 11 o'clock, and was 1.5-mm wide. Corneal topography showed marked central flattening. Six months after treatment, a residual, faint, ring-shaped opacity remained, with a decrease in corneal ectasia. Cross-linking was then performed in the left eye. Different ultraviolet devices were used in the two eyes. On postoperative day 1, the left eye also showed a white ring of stromal opacity. Scheimpflug imaging showed corneal stromal contraction in the zone of whitening. At final examination, >1 year after surgery, corrected visual acuity was 0.00 logMAR with cylinder of 2.00 diopters in both eyes., Conclusions: The bilateral intrastromal corneal changes were innocuous in the long-term, with preservation of good visual acuity and successful stabilization of progressive keratoconus.

Purpose: To identify preoperative parameters that may predict flattening of the keratoconic cornea after collagen crosslinking (CXL)., Setting: Institut für Refraktive und Ophthalmo-Chirurgie (IROC), Zurich, Switzerland., Design: Cohort study., Methods: Patients with verified progressive primary keratectasia received standard corneal CXL. Factors such as corrected distance visual acuity (CDVA) and Scheimpflug tomography (Pentacam) were used to follow the evolution from preoperatively to 12 months after CXL. Statistical analysis included U tests and Spearman rank correlation tests to detect risk factors for flattening of the keratoconus., Results: The study enrolled 151 eyes of 151 patients; more than 80% completed the 12-month follow-up. The flattening rate (flattening of the maximum curvature >1.00 diopter [D]) was 37.7%. A preoperative maximum keratometry (K) reading of more than 54.00 D was identified as the only significant risk factor for this effect (odds ratio, 1.88; 95% confidence interval, 1.01-3.51). A restriction to corneas with a maximum K value greater than 54.00 D would have resulted in a significant flattening in 51% of the cases., Conclusions: Statistically significant flattening occurred during 1 year after CXL in more than 50% of cases when the preoperative maximum K reading was more than 54.00 D. None of the other preoperative parameters evaluated (eg, age, sex, diagnosis, CDVA, corneal shape factors) had a statistically significant impact on corneal flattening after CXL., (Copyright © 2011. Published by Elsevier Inc.)

Purpose: To analyze intra- and postoperative variation in Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments) parameters in 24 keratoconic eyes undergoing corneal cross-linking (CXL)., Methods: In a prospective clinical study, corneal hysteresis (CH), corneal resistance factor (CRF), peak 1 and peak 2 amplitude, corneal-compensated and Goldmann-correlated intraocular pressure (IOP) were evaluated using the ORA. The thinnest cornea point was measured with the Pentacam (Oculus Inc). Corneal topography and endothelial cell count were performed. Measurements were recorded at baseline; intraoperatively after epithelium removal, riboflavin impregnation, and ultraviolet A irradiation; and postoperatively after corneal re-epithelialization and at 1, 6, and 12 months., Results: A statistically significant reduction of the thinnest cornea point from 462±23.24 μm was observed at the end of the CXL procedure intraoperatively and at 1- and 6-month follow-up (P<.05). A significant increase in the thinnest cornea point to 624±31.72 μm was found after re-epithelialization (P<.05), and no significant changes were observed at 1 year postoperatively. Mean CH and CRF did not change significantly after de-epithelialization, but were noted to significantly increase after CXL intraoperatively and postoperatively at 1-month follow-up. At 6 and 12 months postoperatively, CH and CRF were not statistically significantly different from pre-operatively. Peak 1 and peak 2 decreased intraoperatively from 276±52 and 228±47 to 172±42 and 131±42, respectively, at the conclusion of CXL (P<.05), and were noted to increase to 493±41 and 444±51, respectively, at 6-month follow-up. Corneal-compensated IOP and Goldmann-correlated IOP increased at 1 month after CXL (P>.05)., Conclusions: The results showed a significant change in ORA parameters and the thinnest cornea point during and after the CXL procedure and a high correlation between peak amplitudes and corneal asymmetry, providing insight to the bioelastic and biomechanical behavior of the cornea during and after CXL., (Copyright 2010, SLACK Incorporated.)

Purpose: To evaluate the 1-year results of corneal collagen cross-linking (CXL) in eyes with postoperative excimer laser refractive surgery corneal ectasia., Methods: Thirteen eyes of 9 consecutive patients who had undergone excimer laser refractive surgery (photorefractive keratectomy [n = 3], LASIK [n = 10]) with resultant unstable corneal ectasia underwent CXL with photosensitizing riboflavin 0.1% solution and subsequent exposure to ultraviolet radiation. Study eyes underwent complete ophthalmologic examination, endothelial specular microscopy, corneal topography, and aberrometry as well as central pachymetry and Scheimpflug-based topo/tomography preoperatively and at 3-, 6-, and 12-month intervals., Results: Best spectacle-corrected visual acuity (BSCVA) improvement was statistically significant (P < .05) beyond 6 months after surgery (improvement of 0.1 logMAR at 1 year). Mean spherical equivalent refraction and mean refractive sphere reduction (improvement of 1.40 and 1.44 diopters [D], respectively) were statistically significant (P < .05) at 6 months postoperatively. At 1 year after CXL, mean endothelial cell count and keratometry (average SimK decrease of 2.02 D) as well as Klyce and Ambrósio indices did not deteriorate. Coma and spherical aberration did not change significantly. Mean pupil center pachymetry and corneal thickness at 0 and 2 mm from the thinnest corneal point decreased significantly., Conclusions: One year after surgery, CXL appears to stabilize eyes with ectasia consequent to excimer laser refractive surgery and improve BSCVA.

Purpose: To compare geometrical shape factors of keratoconus corneas after cross-linking (CXL) by means of Scheimpflug imaging with those of untreated fellow eyes., Setting: Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland., Methods: Scheimpflug imaging of the anterior segments was performed with the Pentacam (Oculus, Wetzlar, Germany) in 21 patients with progressive keratectasia before and after CXL. Only 1 eye per patient was treated with corneal cross-linking using the riboflavin/UV-A approach, the fellow eye serving as control. The following corneal parameters and their postoperative evolution during 1 year after treatment have been evaluated: minimal curvature radius and its location, thickness at the thinnest point, location of the thinnest point, anterior and posterior elevation, conoid asphericity constants of the anterior and posterior surface, and 7 keratoconus indices. Statistical comparison was performed by means of the Wilcoxon test., Results: None of the treated eyes showed topographic progression in contrast to the untreated group where 8 eyes experienced significant progression. Minimal curvature radius increased significantly after 1 year compared with preoperative (6.14-6.21 mm), whereas in the untreated fellow eye, it significantly decreased (6.94-6.86 mm). Minimal corneal thickness was significantly reduced after treatment (P < 0.002 at 12 months). The cornea showed an evolution toward a more regular shape as indicated by a significant reduction in 4 of 7 keratoconus indices. No complications of CXL occurred in this small study group., Conclusions: After cross-linking, the corneal shape undergoes a process of regularization. This process is active during the first year after treatment and may continue. Longer follow-up is warranted to estimate the full amount of regression of the keratectasia after CXL.