Effect of corneal collagen cross-linking on higher-order aberrations in patients with early keratoconus

Abstract

Background and aim Collagen cross-linking (CXL) is the available treatment to arrest the progression of keratoconus (KC). It consists of photopolymerization of collagen induced by combined action of a photosensitizing substance, and ultraviolet-A light. The aim of the study is to assess higher-order aberrations (HOAs) of cornea in patients with early KC before and after cross-linking using the Bausch & Lomb Zywave II aberrometer. Patients and methods In total, 30 patients (nine males and 21 females), aged 19–35-years old with mild KC. HOAs examination was done using Zywave device before and after corneal CXL and followed up 1, 3, and 6 months postoperative. Results Preoperative and postoperative 1-month Root Mean Square (RMS) of the total HOA differences was statistically insignificant with P value of 0.102, however, preoperative and postoperative 3 and 6 months showed higher significance with P value of 0.007 and P value less than 0.001, respectively. Preoperative and postoperative 1-month RMS of total coma-order aberration differences was statistically insignificant (P=0.211), however preoperative and postoperative 3 and 6 months showed higher significance with P value of 0.024 and value less than 0.001, respectively. Preoperative and postoperative 1- and 3-month secondary astigmatism-aberration differences were statistically insignificant (P=0.070 and 0.216, respectively), however preoperative and postoperative 6 months showed higher significance with P value less than 0.001. Conclusion There is reduction in the parameters of HOAs after CXL in patients with KC, especially total HOA, coma, and secondary astigmatism aberrations.