Abstract
Purpose: :
Degraded peripheral vision has been hypothesized to be a stimulus for the development of foveal refractive error. Contact lenses have been widely used to correct central vision, but their impact on peripheral vision is still not fully understood. The purpose of this study was to use optical model to evaluate the peripheral optics of various contact lenses in isolation thus to better assist us in understanding their peripheral optical performances on human eyes.
Methods: :
An optical design software package (Zemax EE) was used to model peripheral optics of Menicon rigid gas permeable (RGP) lenses and Acuvue 2 soft contact lenses (SCLs). Profiles of sphero-cylindrical power and major higher-order aberrations were computed in 10° steps out to 40° off-axis eccentricity for -3D contact lenses. Optical modeling results were analyzed and compared with previous published experimental data.
Results: :
-3D RGP lens and SCLs had -1.4D and -2.0D dioptric power at 40° eccentricity, respectively. Reduced dioptric power of contact lenses in periphery quantitatively matched with reduced degree of hyperopic field curvature found from experimental data. Cylindrical power increased to 0.3D ~ 0.4D at 40° eccentricity for both lenses. And they both produced 1.2µm coma and 0.15µm spherical aberration at 40° eccentricity.
Conclusions: :
Compared to SCLs, same power RGP lenses had less dioptric power in the periphery. Both RGP lens and SCLs produced the same amount of major higher-order aberrations in a same field angle. These results can be used to predict and understand the peripheral optical performance of contact lenses on human eyes.
Keywords: contact lens • optical properties • refraction