REFRACTIVE ERROR CHANGES IN ADULT HYDROGEL CONTACT LENS WEARERS: LOW vs MEDIUM WATER CONTENT AND DAILY vs EXTENDED WEAR

Vince McGlone

Abstract

Last year we presented data demonstrating that adults wearing daily-wear low water content hydrogel lenses exhibit significantly greater myopic shifts than those wearing medium water content lenses on an extended-wear basis. However, is this effect is due to wearing schedule or lens water content? We conducted a second retrospective study categorizing patients on the basis of wearing schedule; daily-wear vs extended-wear, and water content; low (38%) vs medium (55%) water content. We performed a computer search of over 7000 records for patients over 22 years old, refractive error between -0.25 D and -6.00 D and at least two years of lens wear. A secondary manual search eliminated any patient who had changed lens types or wearing schedule for any more than one week during the two years. The following table shows the number of subjects and mean refractive change over a two year period (all show an increase in myopia) in each subject category: [clean up table] Category N Rx Change Daily Wear/38 36 -0.18 D Extended Wear/38 14 -0.39 D Daily Wear/58 24 -0.16 D Extended Wear/58 38 -0.19 D A two-factor ANOVA revealed that the effect of wearing schedule on refractive change approached significance (F = 3.02, p = 0.085), as did water content (F = 2.69, p = 0.103). There was no significant interaction between water content and wearing schedule. Analysis of groups matched for age and entering refractive error revealed a significant difference between the low and medium water content lenses worn on an extended basis (t = 2.30, p=0.019). These findings show the low water content lenses tend to produce a greater amount of myopic shift than medium water content lenses worn on an extended-wear basis, consistent with our previous report. Additionally, there is a potential relationship between wearing schedule and myopic shift.

Details

Year: 1992

Program Number: 1:45 pm

Author Affiliation: n/a

Co-Authors: Barry Farkas

Co-Author Affiliation: n/a

Room: Great Hall North