The Effect Of Z-Values On The Fit Of Rigid Contact Lenses.

The purpose of this project is to determine the effect of z-values on the fit of rigid contact lenses on corneas with various degrees of eccentricity (different e-values) and make a statistical, graphical, written and video representation of the results. The method of study included: designing a trial lens set with 27 lenses using three different z-values (0.06, 0.10, 0.14) and nine different base curves/z-value (7.40-8.20 in 0.10 mm steps)(constants = OAD 9.2 mm, OZD 7.8 mm, power -3.0 OD). Taking autokeratometer readings of corneal toricity and eccentricity (shape factor or e-values) on 30 patients. Videotaping and evaluating the fit of each z-value on each cornea with the lens of appropriate base curve, paying particular attention to flourescein patterns, centration of lens and lens movement.