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Evaluation of the effect of corneal collagen cross-linking for keratoconus on the ocular higher-order aberrations

Authors El-Massry AA, Dowidar AM, Massoud TH, Tadros BG

Received 19 May 2017

Accepted for publication 27 June 2017

Published 9 August 2017 Volume 2017:11 Pages 1461—1469

DOI https://doi.org/10.2147/OPTH.S142167

Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Amy Norman

Peer reviewer comments 3

Editor who approved publication: Dr Scott Fraser

Ahmed Abdel-Karim El-Massry, Amgad Mostafa Dowidar, Tamer Hamdy Massoud, Baher Guirguis Daoud Tadros

Department of Ophthalmology, Faculty of Medicine, Alexandria University, Alexandria Governorate, Egypt

Background: Corneal collagen cross-linking (CXL) is the only treatment currently available to arrest the progression of keratoconus. The procedure consists of photopolymerization of stromal collagen fibers induced by combined action of a photosensitizing substance (riboflavin or vitamin B2) and ultraviolet-A light.
Purpose: To determine changes in the ocular higher-order aberrations (HOAs) after CXL and its correlation with changes in visual acuity.
Design: Prospective interventional study.
Subjects and methods: This study was conducted on 30 eyes of 16 patients with progressive keratoconus documented between 2012 and 2014. Patients were treated with epithelium-off CXL and followed for a minimum of 6 months. The following ocular HOAs were measured and analyzed using I-Tracey Aberrometer: coma, trefoil, spherical aberration, astigmatism, and total HOAs.
Results: There was statistically significant improvement in uncorrected visual acuity and best-corrected visual acuity between the preoperative and 6-month evaluations (P<0.001). Total HOAs and total coma were statistically significantly reduced at 6 months by 25% and 18%, respectively. Significant improvement was seen in spherical aberration by 8.71% (P<0.001), while no significant change was observed in trefoil and high order astigmatism (P=0.405 and 0.329, respectively). There was a statistically significant change in the average (K) value at the apex between the preoperative values and the 6-month values (P<0.05).
Conclusion: Total HOAs, total coma, and spherical aberrations decreased after CXL. Coma has a direct relationship with the improvement of visual function.

Keywords: collagen cross-linking, progressive keratoconus, ultraviolet irradiation, wavefront aberrations

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