Peripheral Refraction With and Without Contact Lens Correction

Abstract

Purpose Peripheral refractive error degrades the quality of retinal images and has been hypothesized to be a stimulus for the development of refractive error. The purpose of this study was to investigate the changes in refractive error across the horizontal visual field produced by contact lenses (CLs) and to quantify the effect of CLs on peripheral image blur. Methods A commercial Shack-Hartmann aberrometer measured ocular wavefront aberrations in 5° steps across the central 60° of visual field along the horizontal meridian before and after CLs correction. Wavefront refractions for peripheral lines-of-sight were based on the full elliptical pupil encountered in peripheral measurements. Curvature of field is the change in peripheral spherical equivalent relative to the eye’s optical axis. Results Hyperopic curvature of field in the naked eye increases with increasing amounts central myopic refractive error as predicted by Atchison (2006). For an eccentricity of E degrees, field curvature is approximately E percent of foveal refractive error. Rigid gas permeable (RGP) lenses changed field curvature in the myopic direction twice as much as soft contact lenses (SCLs). Both of these effects varied with CLs power. For all lens powers, SCL cut the degree of hyperopic field curvature in half whereas RGP lenses nearly eliminated field curvature. The benefit of reduced field curvature was partially offset by increased oblique astigmatism. The net reduction of retinal blur due to CLs is approximately constant across the visual field. Conclusions Both SCL and RGP lenses reduced the degree of hyperopic field curvature present in myopic eyes, with RGP lenses having greater effect. The tradeoff between field curvature and off-axis astigmatism with RGP lenses may limit their effectiveness for control of myopia progression. These results suggest that axial growth mechanisms that depend on retinal image quality will be affected more by RGP than by SCL lenses.

Power profiles of single vision and multifocal soft contact lenses

“…It has been shown that power distribution across a soft contact lens' optical zone can affect visual performance, peripheral refraction and growth of the eye [4,5,21,[29][30][31][32][33]. Studies found bi-or multifocal contact lens wear to be effective treatments for progressing myopic children [8,34] with some contrary findings [13,14,35].…”

“…Mutti et al, amongst others [4][5][6], also demonstrated that there is an association between myopia in children and relative peripheral hyperopia [7].…”

Comparing the relative peripheral refraction effect of single vision and multifocal contact lenses measured using an autorefractor and an aberrometer: A pilot study

“…11,12 This has led to the use of the mentioned instruments for evaluating the peripheral refractive state of the eye through such specialty lenses. 11,13,14 Recalling that most of these lenses have some sort of multifocality incorporated; this study was designed to compare the contributions of single vision (SVCL) and multifocal contact lenses (MFCL) to the relative peripheral refraction (RPR) profiles as measured with the SN autorefractor and the COAS-HD aberrometer.…”

Ocular Aberrations and Image Quality, Contact Lens and MYOPIA Progression

“…In one of our published studies, [110] the average image blur caused by sphere and cylinder in naked eye increased to 2 D at 35 o periphery relative to the eye's optical axis. SCLs did not have a consistent effect on sphero-cylindrical blur but RGP lenses consistently reduced the blur across the visual field (p < 0.01, non-parametric sign test) by approximately 0.25 diopter.…”