Accelerated Corneal Crosslinking to Arrest Progression of Corneal Ectasia: A Prospective Multicenter Study.

OBJECTIVES: To report the results of epithelium-off accelerated corneal collagen crosslinking (accelerated corneal crosslinking [ACXL]) in patients with progressive keratoconus. METHODS: This prospective, nonrandomized, noncomparative, interventional, multicenter clinical study included all patients who underwent ACXL, either continuous (c-ACXL; 9 mW/cm 2 , 10', 5.4 J/cm 2 ) or pulsed (p-ACXL; 2″ON/1″OFF, 30 mW/cm 2 , 4.5', 5.4 J/cm 2 ) between January 2014 and May 2017. Best-corrected visual acuity, sphere, cylinder, spherical equivalent, and topographical keratometry data were collected preoperatively and at 1, 3, 6, 12, 18, and 24 months postoperatively. RESULTS: Ninety-six eyes of 78 patients were included. The mean age was 20.8±4.4 years (14-33) for c-ACXL and 26.7±7.7 years (12-37) for p-ACXL. The mean best-corrected visual acuity was 0.4±0.4 for c-ACXL and 0.01±0.1 for p-ACXL preoperatively, and 0.3±0.3 ( P =0.0014) and -0.01±0.1 ( P =0.1554), respectively, at the last follow-up. The subjective sphere and spherical equivalent did not show statistically significant differences between the time points ( P >0.05). The subjective cylinder showed significant differences ( P =0.0013 for c-ACXL; P =0.0358 for p-ACXL). Keratometric values (K steep , K flat , and SimK) remained stable, with no statistically significant differences ( P >0.05). No major complications were noted. CONCLUSIONS: Both c-ACXL and p-ACXL are equally safe and effective ACXL protocols in stabilizing the progression of keratoconus and can be considered alternatives to the conventional Dresden protocol.

Challenges in using both eyes of the same patient when evaluating the results after implantation of intrastromal corneal ring segments.

PURPOSE: To assess correlation between results from both eyes of the same patient after implantation of intrastromal corneal ring segments (ICRS) and define whether they can be used together in clinical studies. METHODS: A review of medical records of 74 patients with keratoconus implanted with bilateral Ferrara ICRS at Centro de Oftalmología Barraquer from January 2005 until December 2014. Data were collected on uncorrected visual acuity, best-corrected visual acuity and subjective refractive values (sphere, cylinder and axis). RESULTS: A total of 39 patients were male (53%), and 35 were female (47%). Mean age at the time of implantation was 32.5 ± 10 years. No major complications occurred. A significant correlation between the results from right and left eyes was found (p < 0.0043), indicating that both eyes significantly resembled each other. No significant interaction in the magnitude of change between eye and surgery was observed under classic and mixed models. CONCLUSION: Based on our data, whenever application is not possible under mixed-model analyses, we recommend the use of a first eye operated only, either right or left, in order to avoid bias and errors derived from autocorrelation and guarantee the independence of the registered observations.