Purchase this article with an account.
H.H. Dietze, M.J. Cox; Correcting Ocular Spherical Aberration with Soft Contact Lenses . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3286.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Background: To assess the effect of modifying the front surface asphericity of rotationally symmetrical soft contact lenses (SCLs) on the spherical aberration (SA) and visual performance of the eye-SCL system. Methods: One spherical and two front surface aspheric SCLs were fitted to one eye of each of 19 ametropic (16 myopes, 3 hyperopes) subjects (age 22 ± 4.5) with corrected logMAR visual acuity better than 0.0 and no ocular pathology. Following measurement of the subject's SA, one aspheric SCL was designed to neutralise the SA of the subject when wearing the SCL (the ‘custom made' lens) and one to minimise the SA of the SCL alone (the ‘aberration free' lens). Hartmann-Shack aberrometry measurements were made of the Zernike coefficients and the root-mean-square of the wavefront aberration with and without each SCL on the eye. logMAR visual acuity and contrast sensitivity at 6, 12 and 24 c/deg were measured with each SCL and with the best correcting spectacle lens. Residual refractive error with the SCL was corrected using spectacle lenses. Results: The custom made aspheric SCLs corrected, on average, 60% of the ocular SA. For our cohort of subjects, ANOVAs followed by post-hoc testing where appropriate showed the following statistically significant differences. The SA of the eye-SCL system was increased with aberration free lenses (p < 0.01), was reduced by custom made lenses (p < 0.01) and was unchanged by spherical lenses when compared to a spectacle lens correction. No change in the root-mean-square wavefront aberration or logMAR visual acuity was found with any of the SCL types compared to the spectacle lenses. Contrast sensitivity at 6 c/deg was higher with the custom made SCLs (p < 0.01) and with the standard SCLs (p < 0.05) compared to the spectacle lenses. At 12 c/deg it was higher with the custom made SCLs (p < 0.05). Conclusions: Individually designed SCLs can reduce the level of SA of the eye-SCL system. The negative SA produced by negatively powered standard SCLs partly cancels the on average positive ocular SA in myopes. Aberration free SCLs can increase the SA compared to standard lenses in a population containing a high proportion of myopes. Visual benefits of correcting the SA using SCLs are small and hard to predict.
This PDF is available to Subscribers Only