Biomechanical and Refractive Results of Transepithelial Cross-linking Treatment in Keratoconic Eyes

Abstract

Purpose: To analyze change in visual acuity (VA), refractive outcomes, corneal compensated intraocular pressure (IOPcc), corneal hysteresis (CH) and cornea resistance factor (CRF) after transepithelial cross-linking (CXL) treatment. Setting: Kudret Eye Hospital, Ankara, Turkey Materials and methods: A total of 32 eyes of 22 patients diagnosed with keratoconus were included in this retrospective study. Changes in VA, spheric and cylinderic refraction for all eyes were analyzed before and 3 months after transepithelial CXL. In addition, a subset of 14 eyes had data acquired using the ocular response analyzer (ORA), and for these eyes, IOPcc, CH and CRF were recorded as well as a measurement of the amplitude of the first peak in the infrared signal (peak 1), used to identify the inward applanation event. The ORA parameters were also compared before and 3 months after treatment. Results: Uncorrected and best corrected VA increased 1.76 and 1.61 Snellen lines (p < 0.05); spheric and cylinderic refractions improved 0.74 and 0.43 D (p > 0.05) respectively. Mean changes in IOPcc, CRF and CH were not significantly different (p > 0.05). However, mean peak 1 signal value increased significantly (p < 0.05). Conclusion: Transepithelial CXL is effective in VA improvement in the short-term with an increase in the peak 1 signal value which is consistent with an increase in stiffness of cornea, whereas IOPcc, CRF and CH values remained the same.