The Influence of Soft Contact Lens Materials on the Central, Para-Central and Peripheral Corneal Endothelium

Title: The influence of soft contact lens materials on the central, para-central and peripheral corneal endothelium prior to and following two weeks cessation of soft contact lens wear. Purpose: To examine the influence of a variety of soft contact lens (SCL) materials on the central, para-central and peripheral corneal endothelium measurements, prior to and following two weeks cessation of SCL wear. Methods: Endothelial measurements were taken using the CEM-530 (Nidek, Japan) specular microscope. Full-time SCL wearers (n = 31 eyes) were compared to a non-contact lens (NCL) control group (n = 28 eyes) of a similar age. Seven areas of the endothelium were analysed: centrally, para-centrally (0.6mm from centre) at 0°, 90°, 180°, 270° and the superior and inferior periphery (3.7mm from center). Parameters examined were endothelial cell density (ECD; cell/mm2), mean cell area (MCA; µ2), coefficient of variation (COV) and hexagonality (%). Results: Prior to SCL cessation, two-way ANOVA testing resulted in significant differences between silicone hydrogel (SiH) SCL materials for the COV at 0º, with generation 2 SiH wearers showing increased COV (27.67 ±3.78) compared to generation 3 SiH wearers (24.50 ±3.73, p=0.01). COV at the superior periphery was significantly lower in the NCL group (25.63 ±2.79) compared to the hydrogel group (29.92 ±6.22, p=0.02). The MCA in the inferior periphery was also significantly higher in the NCL group (346.92 ±36.75) compared to the hydrogel group (314.92 ±16.57, p=0.02). Following 14 days SCL cessation the differences in measurements taken between day 0 and day 14 were calculated and analysed, no statistically significant differences in stability of endothelial parameters were detected between NCL and SCL material groups (all p values \u3e0.05). Conclusion: SCL wear has an effect on para-central and peripheral corneal endothelial measurements in SCL wearers compared to NCL wearers, with largest significant differences seen between NCL and hydrogel SCL wearers. Following two weeks SCL cessation, there was relative stability of all endothelial measurements, regardless of which SCL material was worn prior to SCL cessation