Assessment of Aphakic Spectacle Lenses: High Power Flatback Lenses for the Correction of Aphakia

Abstract

The spectacle wearing aphakic patient has severe optical and other problems compared with most other spectacle wearers. Recently, aspheric lenses with relatively flat back surfaces have been introduced for the correction of aphakia which are claimed to (i) reduce spectacle magnification and peripheral distortion, and (ii) increase the apparent visual field. A theoretical assessment of typical aspheric planoconvex ("flatback") lenses is presented in which optimal asphericities for the solution of different aphakic lens problems is determined and a preliminary assessment of the new aphakic lenses is given. The best asphericity of correction of off-axis aberrations with foveal vision of a rotating eye is less than that for correction of peripheral visual problems. Although the new aphakic lenses have less spectacle magnification and improved cosmetic appearance relative to previous types, the amount of asphericity seems to be insufficient to markedly improve peripheral visual performance.