Higher Order Aberrations Induced by Soft Contact Lens Use for Myopic Correction

Abstract

Abstract: : Purpose: To evaluate and compare the wavefront characteristics in normal eyes before and after being fitted with hydrogel soft contact lenses for correction of myopia. Methods:Higher order aberrations (HOA) of 30 eyes of 15 soft contact users who had no ocular diseases other than myopia were quantified with a Nidek Marco 3–D Wave wavefront analyzer. Zernike’s polynomial was used to describe the wavefront measurements. RMS values of the total HOAs, total coma, total trefoil and total spherical aberrations were obtained in the same eyes before and after soft contact lenses were inserted. Similar sets of data were also obtained in different brands of soft contact lenses of the same power inserted in the same eyes. We used paired sample t–test to analyze the data. Results:Mean values (RMS) for all higher order aberration components from before to after soft contact lens insertion were: total HOA from 0.364µm to 0.456µm (P=0.01), total coma from 0.203µm to 0.220µm (P=0.51), total trefoil from 0.193µm to 0.254µm (P=0.06) and total spherical aberration from 0.126µm to 0.148µm (P=0.36). Induced HOA also varies among different brands of soft contact lens when power and eyes were controlled. Conclusions: Wavefront analysis showed soft contact lenses for myopia induced a significant increase in HOA. Though total HOA with contact lens use was statistically significant, total coma, trefoil and spherical aberrations were also higher in contact lens use but were not statistically significant when individually evaluated. Comparison with LASIK induced HOA will be presented.

Keywords: cornea: clinical science • contact lens • refractive surgery: corneal topography