Comparison of Corneal Stromal Demarcation Line Depth in Epi-off and Epi-on Corneal CrossLinking Using Anterior Segment Optical Coherence Tomograph

Abstract

Objective: To compare the corneal stromal demarcation line depth after Epithelium-On and Epithelium-Off corneal crosslinking in patients with keratoconus using anterior segment Optical Coherence Tomography (AS-OCT).

Study design: Quasi-experimental study.

Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi Pakistan from Jun 2018 to Jun 2019.

Methodology: This study included patients (60 eyes) with progressive keratoconus treated with procedure CXL (corneal cross linkage). There were 30 eyes in each group. Two different protocols of Corneal cross linkage were performed, and patients were divided into two groups according to protocol: 1) epithelium-on Corneal cross-linkage, 2) epithelium-off Corneal crosslinkage. In the First-Group, epithelium-on Corneal cross-linkage,corneal epithelium was not removed, riboflavin solution was instilled on the cornea for one hour, and the cornea was exposed to Ultraviolet A rays. In Epithelium off Corneal cross-linkage,after epithelium was removed by spatula, riboflavin solution was instilled for 30 minutes, and Ultraviolet-A rays were focused on the cornea. After one month of the procedure, Anterior segment Optical Coherence Tomography was performed.Demarcation line depth was measured in treated corneas in all patients from both groups, and findings were compared.

Results: The stromal demarcation line depth was similar in both groups, and there was no statistical difference between the groups. The mean value of demarcation line depth was 277.13±107.09 цm (p>0.05).

Conclusion: Corneal stromal demarcation line depth after both procedures was similar in both groups after one month of Corneal cross-linkage, so it was concluded that epithelium-on Corneal cross-linkage was comparable to epithelium-off Corneal cross-linkage.