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Thesis

The clinical success of empirically fit soft toric contact lenses versus fitting using diagnostic trial lenses and ToriTrack

1 May 2005

Abstract

To improve the efficiency of fitting toric soft contact lenses Cooper Vision designed Tori Track, software that calculates the final prescription using any trial lens of known power and SCOR without the estimation of rotation. The clinical success of traditional empirical fitting versus using a randomly selected diagnostic lens with Tori Track was compared using 28 eyes with at least 1.50D of cylinder. The initial visit included empirically fitting the subjects with Frequency 55 toric lenses by vertex correcting their manifest refraction. Following equilibration and an acceptable fit, acuities were taken using Snellen and high and low contrast Bailey Lovie charts. On a second visit, a -3.00-1.25 x040 lens was fit on all the patients and a SCOR was performed. ToriTrack was then used to predict the final lens parametres. The results of the initial visit were compared to the second visit. We found that on average ToriTrack predicted the final lens to undercorrect by 0.33D (spherical equivalent) more than the initial visit. Cylinder power was consistant between both parts, but the axis showed a shift of 15 degrees in 14 out of the 28 eyes. Even with the large axis shift, acuities were not significantly affected. Using ToriTrack and a diagnostic lens did not appear to be significantly more efficient than emprically fitting the lens. However, ToriTrack was useful for the built in vertex calculator, comprehensive catalogue of CooperVision lenses and maintaining patient records.


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