Since the recent introduction of gas permeable hard contact lenses, a great deal of research has been conducted that proves the superiority of these lenses over standard PMMA lenses in preventing corneal edema. However, the introduction of gas permeable contact lenses by several different contact lens manufacturers necessitates some direct comparisons. This senior research study involves the contralateral comparison of the Polycon II and the Boston II gas permeable contact lenses. The researchers are interested ~n comparing the two lenses for subjective patient comfort and acuity as well as the effects on corneal physiology by measuring the amount of corneal thickening us1ng the Dicon Model II RK Digital Computer Pachometer . Fourteen subjects participated 1n the study and were divided into four groups: PMMA lens wearers, soft lens wearers, gas permeable lens wearers, and subjects with no previous contact lens wear experience. All lens parameters were ordered according to the stock lens specifications of the Polycon II lens in an effort to match as closely as possible all parameters with the exception of back vertex power. Twelve of the fourteen subjects were fit with 8.5 mm OAD lenses and the remaining two subjects were fit with 9.5 mm OAD lenses. All lenses were fit approximately 1.00 diopter steeper than Kf at the diagnostic fitting. Three pachometric measurements were made on each subject. The first prior to dispensing the lenses and the last two measurements at one week and three weeks respectively. A comparison of pachometric measurements using a two-tailed analysis of variance will be performed on collected data.
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