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Purpose: This study aimed to analyze variations in intraoperative corneal thickness during corneal cross-linking in patients with keratoconus and to investigate its possible correlation with presurgical maximal keratometry (Kmax) and pachymetry., Methods: This was a prospective case series. We used a method similar to the Dresden protocol, with the application of hydroxypropyl methylcellulose 0.1% hypo-osmolar riboflavin in corneas between 330 and 400 µm after epithelium removal. Corneal thickness was measured using portable calipers before and immediately after epithelium removal, and 30 and 60 min after the procedure., Results: The 30 patients in this study were followed up for one year. A statistically significant difference was observed in pachymetry values during the intraoperative period (p<0.0001) and an increase of 3.05 µm (95%C1: 0.56-5.54) for each diopter was seen after epithelium removal (p0.019). We found an average Kmax difference of -2.12 D between men and women (p0.013). One year after treatment, there was a statistically significant reduction in pachymetry (p<0.0001) and Kmax (p0.0170) values., Conclusions: A significant increase in pachymetry measurements was seen during the procedure, and most patients showed a regression in Kmax and pachymetry values one year after surgery.

Purpose: To assess corneal thickness changes with isotonic riboflavin (RF) solution with hydroxylpropyl methylcellulose in patients undergoing accelerated corneal collagen crosslinking (CXL) with and without an eyelid speculum., Methods: Fifty-two eyes of 48 patients with progressive keratoconus were enrolled in this study. The patients in this study were divided into 2 groups: in group 1 an eyelid speculum was removed during 20-minute RF (0.1%) + hydroxylpropyl methylcellulose (Mediocross M; Avedro Inc, Waltham, MA) instillation, and in group 2 the eyelid speculum was retained in place during the entire CXL procedure. All patients underwent accelerated CXL using continuous ultraviolet-A (UVA) light exposure at 9 mW/cm for 10 minutes; total energy dose was 5.4 J/cm. Intraoperative ultrasound pachymetry measurements were obtained before and after epithelial removal, after RF loading, and after UVA light exposure at 5 and 10 minutes., Results: The preoperative pachymetric measurements decreased in both groups after the removal of epithelium [group 1 (n = 26): -25 μm, group 2 (n = 26): -31 μm, P = 0.234]. Although the thinnest pachymetry significantly increased after soaking in both group 1 (52.26 μm) and group 2 (27.88 μm, P < 0.001), closure of the eyelids during RF instillation further increased the pachymetry readings (P < 0.0001). The corneal thickness remained stable in both groups during UVA irradiation at 5 and 10 minutes (P > 0.05)., Conclusions: Closure of the eyelids further induces corneal swelling that may offer an advantage to improve safety of the procedure particularly in thin corneas.

Purpose: To compare the clinical outcome 2 years after corneal collagen cross-linking (CXL) with conventional and accelerated ultraviolet A (UVA) irradiation using riboflavin with hydroxypropyl methylcellulose., Methods: Prospective randomized controlled study. Forty patients with keratoconus (40 eyes) were randomized to either CXL using conventional 3 mW/cm UVA irradiation for 30 minutes (CXL30 group) or accelerated 9 mW/cm UVA irradiation for 10 minutes (CXL10 group). In both groups, a solution of 0.1% riboflavin with 1.1% hydroxypropyl methylcellulose (methylcellulose-riboflavin) was used. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), and Scheimpflug tomography were performed at baseline and after 24 months., Results: Both groups had statistically significant improvement in CDVA and maximum keratometric reading compared with baseline; however, with no statistically significant difference in the change between the 2 groups. No significant changes in flattest, steepest and mean keratometry (K1, K2 and K mean) were found in either of the groups. There were no statistically significant changes in ECD in either group after 2 years or in the difference in the change between the 2 groups. A literature review showed comparative clinical outcome after accelerated CXL compared with conventional CXL; however, in several studies, there was a tendency for less pronounced corneal flattening after accelerated CXL., Conclusions: Improvement in visual acuity and maximum keratometric reading 2 years after CXL was found after both conventional and accelerated UVA irradiation using methylcellulose-riboflavin. This suggests that when using riboflavin with methylcellulose, the less time-consuming accelerated protocol is a valuable and effective option in CXL treatment.

Purpose: To compare the demarcation line depth after contact lens-assisted corneal crosslinking (CXL) for progressive keratoconus using dextran-based and hydroxypropyl methylcellulose (HPMC)-based riboflavin solutions., Setting: Advanced Eye Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India., Design: Retrospective case series., Methods: Patients with preoperative epithelium-on (epi-on) minimum corneal thickness between 350 μm and 450 μm having contact lens-assisted CXL for progressive keratoconus were crosslinked with isoosmolar 0.1% riboflavin in 20% dextran 500 or HPMC 1.1%. The primary outcome measure was the mean demarcation line depth measured 1 month postoperatively on anterior-segment optical coherence tomography. The secondary outcome measure was change in endothelial cell density (ECD) 6 months from baseline., Results: The study comprised 21 patients (21 eyes, 9 in the HPMC group and 12 in the dextran group). The mean demarcation line depth was deeper in the HPMC group (308.22 μm ± 84.19 [SD]) than in the dextran group (235.33 ± 64.87 μm) (P < .04). This difference remained significant (P = .02) even after controlling for the preoperative lesser epi-on minimum corneal thickness in the HPMC group (385.56 ±13.81 μm) versus the dextran group (413.08 ± 29.58 μm) (P < .02). The ECD 6 months after contact lens-assisted CXL was comparable to the baseline levels in both groups (P = .19 and P = .09, respectively)., Conclusion: During contact lens-assisted CXL, HPMC-based riboflavin seemed to be associated with a deeper demarcation line than dextran-based riboflavin, although both solutions were safe for the endothelium at 6 months., (Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the clinical and microstructural results of accelerated 15 mW pulsed-light corneal crosslinking (CXL) to treat progressive keratoconus., Setting: Siena Crosslinking Center, Siena, Italy., Design: Prospective case series., Methods: After epithelium removal (with Epi-Clear) and 10 minutes stromal soaking with riboflavin 0.1% hydroxypropyl methylcellulose solution, all eyes had 15 mW/cm 2 pulsed-light epithelium-off accelerated CXL for 6 minutes of ultraviolet-A (UVA) irradiation (1 second on/1 second off), maintaining a total UVA exposure of 12 minutes at a fluence of 5.4 J/cm 2 . The 2-year follow-up examination included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, Scheimpflug tomography, in vivo confocal microscopy (IVCM), and spectral-domain optical coherence tomography (SD-OCT)., Results: The study comprised 132 eyes of 96 patients (mean age 23.7 years ± 4.3 [SD]) with stage II keratoconus. The change in UDVA and CDVA was statistically significant, from 0.51 ± 0.106 logarithm of the minimum angle of resolution (logMAR) at baseline to 0.309 ± 0.074 logMAR (P = .0001) and 0.271 ± 0.144 logMAR at baseline to 0.135 ± 0.100 logMAR (P = .0023), respectively. Coma values measured by Scheimpflug analysis showed a statistically significant improvement beginning with the first postoperative month (P = .0004). The IVCM scans documented basal epithelial healing occurring 72 hours after treatment associated with the presence of subepithelial nerves. The SD-OCT scans performed in the central 6.0 mm of corneal diameter documented a demarcation line at a mean depth of 280 ± 32 μm., Conclusion: The 15 mW/cm 2 pulsed-light epithelium-off accelerated CXL was effective and safe, stabilizing keratoconus progression through 2 years of follow-up., (Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to monitor corneal pachymetry changes during accelerated collagen cross-linking (CXL) for keratoconus while using isotonic riboflavin with HPMC., Methods: All consecutive patients who underwent CXL for progressive keratoconus, using accelerated protocol and isotonic riboflavin with HPMC, from December 2012 to September 2013 were included in the study. The corneal pachymetry measurements were obtained at different time points: after epithelial removal, after riboflavin application for 20 minutes, and after ultraviolet A irradiation for 10 minutes at 9 mW/cm., Results: A total of 14 eyes of 14 consecutive patients were included in this study. The mean age of the patients was 19 ± 8 years. There were 8 left eyes and 6 right eyes. After epithelial debridement, the thinnest pachymetric readings were between 324 and 452 μm (average, 401.4 ± 40.7 μm). No significant difference (P = 0.80) was found between the deepithelialized corneal thickness and after 20 minutes of isotonic riboflavin with HPMC (pachymetric average, 405.3 ± 37.5 μm). Pachymetric average after ultraviolet A irradiation was 419.29 ± 20.60 μm. There was no statistical significant change in the corneal thickness after the irradiation (P = 0.24)., Conclusions: During corneal CXL using isotonic riboflavin and HPMC with accelerated cross-linking protocol, no significant decline in the corneal thickness was demonstrated.