Central and Peripheral Corneal Thickness Changes during Scleral Contact Lens Wear

Abstract

Purpose : To evaluate corneal thickness changes in the center and periphery after 5 hours of scleral contact lens wear

Methods : Subjects with no history of contact lens wear in the past 12 months and presenting with no active ocular disease were recruited. Scleral lenses of fluorosilicone acrylate material (hofocon A; 15.6mm diameter; 97 Dk; 1.44 refractive index; average lens thickness of 400 µm) were used. Ocular surface examination with slit lamp biomicroscope was performed before and after 5-hr lens wear. Central, peripheral corneal thicknesses (nasal and temporal quadrants) and central post-lens tear thickness of each eye were measured by high-resolution spectral domain optical coherence tomography (OCT) (ENVISU 2300; Bioptigen Inc.) before and during lens wear, as well as after lens removal. Mixed effect model assigning repeated measurements as random effect was employed to examine the corneal thickness changes from baseline in both center and periphery.

Results : A total of 10 sets of central cornea and 20 sets of peripheral cornea OCT images were analyzed for percent corneal thickness changes (%CTΔ) from 5 subjects (Mean±SD age: 20.2±1.8 years). Central %CTΔ after 5-hr lens wear was 0.8±0.9% (p=0.02) and peripheral %CTΔ were 1.4±0.7% nasally (p=0.62) and 1.4±0.9% temporally (p=0.56). Central %CTΔ reached its peak at 2 hours after lens wear (1.0±0.4%; p=0.003). Mean±SD of central post-lens tear thickness before lens removal was 188.4±99.8µm. Of interest, 40% eyes exhibited signs of microcystic changes of corneal epithelium in the periphery, which showed no qualitative trend with %CTΔ.

Conclusions : Using a novel image processing technique, we were able to monitor peripheral corneal thickness change after scleral lens wear but it was not considered significantly different from baseline. We found a change in central corneal thickness however it may not be considered clinically significant. There was no relationship between corneal thickness changes and the ocular sign of microcystic changes of corneal epithelium.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.