Abstract
Abstract: :
Purpose: To gauge the effects of spherical aberration on subjective and objective visual function and to estimate the level of spherical aberration needed perceive degradation of in image or point source of light. Methods: A contact lens model of spherical aberration using Hioxifilcon A in a standard base curve of 8.3mm with a central plano optical zone of 6.0mm was used. The periphery was a hyperopic aspheric design which induced spherical aberration ranging from one to ten diopters in one diopter increments. After administration of phenylephrine 2.5%, forty eyes of forty masked volunteers with myopia ranging from 0 to –4.00 diopters and less that 0.75 diopters of cylinder underwent ray tracing aberrometry visual acuity measurement reported using the logMAR scale, contrast sensitivity using the Pelli–Robson chart, glare using the Brightness Acuity Tester, and measurement of halo size using a standardized point source. The volunteers were then fit with contact lenses by a masked examiner and the aberrometry, visual acuity, contrast sensitivity, glare, and halo size measurements were repeated. Results: In contact lenses with higher levels of spherical aberration, subjective and objective measures of visual function were degraded. Not all subjects were equally affected by the same level of induced spherical aberration. Conclusion: In this contact lens model of spherical aberration, we have characterized the subjective and objective changes induced by varying levels of spherical aberration.