Effect of Wearing Different Soft Contact Lens Material & Base Curve on the Objective Refraction

Abstract

Purpose : The study investigated the effect of different soft contact lens material & Base curve on over-refraction using ARK and corneal topography measurement. Methods : 20 participants with mean corneal curvature of 7.77±0.24 mm (mean age = 24.73 ±2.52 years) volunterred. Each participant worn –3.00 D of hydrogel contact lenses and silicone hydrogel lenses with BC 9.0 mm & 8.5 mm in random order. The refraction (KR-8100P) and corneal topography measurement (Oculus Keratograph 5M) were conducted and difference of before and while wearing the lenses were analysed after –3.00 D compensation. Results : There were no statistically significant for ARK and topography measurmenet among 4 lenses (ARK p=0.691, Topography p=0.438). Differences by material were 0.05±0.05 for hydrogel and 0.12±0.04 for silicone hydrogel (p=0.327). Difference by BC were 0.06±0.05 for BC 9.0 and 0.11±0.05 for BC 8.5 (p=0.482). For Topography measurement, differences by material were 0.30±0.05 D for hydrogel and 0.38±0.05 D for silicone hydrogel (p=0.298). Difference by BC were 0.36±0.04 D or BC 9.0 and 0.32±0.06 D for BC 8.5 (p=0.537). Conclusion : Material and BC did not make any difference on the objective refraction, however corneal topography showed more than 0.25 D map changes, therefore cautious approaches needs to be made when prescribing contact lens.