Long-term Results of an Accelerated Corneal Cross-linking Protocol (18 mW/cm2) for the Treatment of Progressive Keratoconus.

PURPOSE: To compare the long-term outcomes of accelerated and standard corneal cross-linking protocols in the treatment of progressive keratoconus. DESIGN: Prospective randomized clinical trial. METHODS: Thirty-one eyes with keratoconus were treated with an accelerated protocol (18 mW/cm(2), 5 min) and all contralateral eyes were treated with the standard method (3 mW/cm(2), 30 min) using the same overall fluence of 5.4 J/cm(2). RESULTS: At 18 months after the procedure, the standard group showed significant improvement in spherical equivalent (P < .05), K-readings (P < .05), Q value (P < .05), index of surface variance (P < .05), and keratoconus index (P = .008) and decline in central corneal thickness (P < .05), but no significant change in visual acuity, corneal hysteresis, corneal resistance factor, P2 area, or endothelial cell density. In the accelerated group, central corneal thickness was the only parameter with statistically significant change. However, neither of these parameters showed significant differences between the standard and the 18 mW/cm(2) accelerated protocol, except K-reading (P = .059) and index surface variance (P = .034). CONCLUSION: An accelerated cross-linking protocol, using 18 mW/cm(2) for 5 minutes, shows a comparable outcome and safety profile when compared to the standard protocol, but better corneal flattening is achieved with the standard method than the accelerated method. Overall, both methods stop the disease progression similarly. This study will continue to examine more long-term results.

Evaluation of the Results of Using Toric IOL in the Cataract Surgery of Keratoconus Patients.

PURPOSE: To evaluate the results of using AcrySof toric intraocular lenses (IOLs) in the cataract surgery of patients with keratoconus (KCN). METHODS: In this study, 23 eyes of 17 patients with KCN who underwent cataract surgery using the toric IOL were evaluated. The amount and axis of the corneal astigmatism were measured by manual keratometry, corneal topography, refractive map of the Pentacam, and equivalent K reading of the Pentacam in all patients. RESULTS: The mean uncorrected visual acuity increased significantly 3 months after the surgery (P<0.01). The mean best-corrected visual acuity was 0.28±0.10 logMAR, 0.51±0.52 logMAR, and 0.83±0.55 logMAR before the surgery and 0.16±0.09 logMAR, 0.18±0.12 logMAR, and 0.35±0.13 logMAR after the surgery in the mild, moderate, and severe KCN groups, respectively (P<0.01). The mean IOL rotation was 2.50±1.18 degrees, 2.50±1.51 degrees, and 2.67±1.15 degrees in the mild, moderate, and severe KCN groups. The lowest mean absolute error was seen in the mild and moderate KCN groups with corneal topography-derived keratometry using the SRK/T formula and in the severe KCN group with corneal topography-derived keratometry and manual keratometry using the SRK/T and SRK II formulas. CONCLUSIONS: The use of toric IOLs resulted in desirable vision and refraction in the cataract surgery of patients with nonprogressive KCN. As for determining the IOL power, it seems that keratometry derived from the 3 mm central zone in the axial map of corneal topography using the SRK/T formula has the lowest error.

Short-term comparison of accelerated and standard methods of corneal collagen crosslinking.

PURPOSE: To compare the 6-month results of accelerated and standard collagen crosslinking (CXL) treatment of progressive keratoconus. SETTING: Noor Eye Hospital, Tehran, Iran. DESIGN: Prospective randomized clinical trial. METHODS: Two groups of eyes (intervention and control) received corneal collagen crosslinking (CXL) treatment. The intervention group received accelerated CXL (18 mW/cm(2), 5 minutes), and the control group received standard CXL (3 mW/cm(2), 30 minutes). The eyes were evaluated for changes in the visual indices, refraction, and topography preoperatively and 1, 3, and 6 months postoperatively and regarding corneal rigidity indices and the endothelial cell count (ECC) preoperatively and at 6 months. RESULTS: The study evaluated 62 eyes (31 patient) in 2 groups. The mean changes in uncorrected (P = .733) and corrected (P = .646) distance visual acuities and manifest refraction spherical equivalent (P = .598) did not differ statistically significantly between the 2 groups. The central corneal thickness was higher in the standard group than the accelerated group (P = .025). The mean decrease in the maximum keratometry (K) (P = .865) and mean K (P = .974) and the mean changes in the asphericity (P = .272) were not statistically significantly different between the 2 groups. The mean changes in corneal hysteresis (CH) (P = .548) and the corneal resistance factor (CRF) (P = 1.000), CH-CRF (P = .282), and the area under the peak 2 (P = .260) were similar in both groups. The mean decrease in the ECC was not statistically significantly different between the 2 groups (P = .218). CONCLUSION: Based on 6-month results, accelerated and standard corneal CXL arrested the progression of keratoconus similarly. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.