Effects of soft contact lenses on contrast sensitivity

This study attempts to resolve the conflicting reports relative to contrast sensitivity function (CSF) and soft contact lens wear. Contrast sensitivity was measured at six spatial frequencies for 19 subjects (38 eyes) when corrected with either spectacles or soft lenses. Measured amounts of residual astigmatism and/or sphere were corrected using a trial frame and lenses. Additionally, data were evaluated on more than one occasion in order to investigate the effect of time upon visual performance with the lenses. The results indicate a measurable decrease in contrast sensitivity for only the highest of the spatial frequencies tested (22.8 c/deg) when soft lenses were worn. For those eyes demonstrating a clinically significantly decrease in contrast sensitivity, responsibility appears to be shared by both the contact lens and the cornea. There were no significant changes in CSF over time.