Purpose: To evaluate the effect of corneal collagen cross-linking (CXL) on corneal innervation, corneal sensitivity, and tear function in patients with keratoconus.
Design: Prospective, interventional case series.
Participants: Twenty-four patients with bilateral keratoconus (30 eyes) who presented to the Institute of Vision and Optics, University of Crete, from May 2008 to October 2008.
Methods: Patients underwent CXL. Confocal microscopic analysis of corneal sub-basal nerve plexus (total nerve length per image), corneal sensitivity (assessed with the Cochet-Bonnet esthesiometer), basic tear secretion (assessed with Schirmer's I test with anesthesia), and tear film stability (evaluated by means of tear film break-up time [TFBUT]) were assessed preoperatively and at 1, 3, 6, 9, 12, 18, and 24 months postoperatively.
Main outcome measures: Comparisons between preoperative and each postoperative value of total nerve length per image, corneal sensitivity, Schirmer's I test results, and TFBUT.
Results: Total nerve length per image and corneal sensitivity were significantly decreased until postoperative month 6 (for both parameters: P<0.05 paired-samples t test at 1, 3, and 6 months postoperatively). Total nerve length per image tended to increase up to 2 years postoperatively, when it reached the preoperative level, but differences with the preoperative values after the sixth post-CXL month were insignificant. The results of Schirmer's I test and TFBUT had no statistically significant difference at any time point.
Conclusions: A transient decrease in corneal innervation and corneal sensitivity can be observed up to 6 months after CXL. No significant effect of CXL could be detected on basic tear secretion and tear film stability in our group of patients.
Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.