The concentric distribution of protein on patient-worn hydrogel lenses.

Abstract

We investigated the concentric distribution of protein on patient-worn hydrogel lenses. We measured patient-worn lenses for diameter, sagittal depth, and thickness so that the surface area of each lens could be calculated. The lenses were then cut with a circular blade to give an inner circular core and an outer concentric ring having approximately equal lens surface area. Total protein was then determined for each lens half using a modified ninhydrin procedure. The protein deposition on the inner core was compared to the amount on the outer ring for each of the four FDA lens groups. Lenses of group III and group IV were found to deposit significantly more protein on the outer portion while the other groups showed essentially the same amount on both halves. This finding indicates that the type of lens has an effect on the distribution pattern of protein.