Visual Performance with Lenses Correcting Peripheral Refractive Errors

Abstract

To design and manufacture lenses to correct peripheral refraction along the horizontal meridian and to determine whether these resulted in noticeable improvements in visual performance. Subjective refraction of a low myope was determined on the basis of best peripheral detection acuity along the horizontal visual field out to ±30° for both horizontal and vertical gratings. Subjective refraction was compared to objective refractions using a COAS-HD aberrometer. Special lenses were made to correct peripheral refraction, based on designs optimized with and without smoothing across a 3-mm diameter square aperture. Grating detection was retested with these lenses. Contrast thresholds of 1.25-min arc spots were determined across the field for the conditions of best correction, on-axis correction, and the special lenses. The participant had high relative peripheral hyperopia, particularly in the temporal visual field (maximum, 2.9 D). There were differences >0.5 D between subjective and objective refractions at a few field angles. On-axis correction reduced peripheral detection acuity and increased peripheral contrast threshold in the peripheral visual field, relative to the best correction, by up to 0.4 and 0.5 log units, respectively. The special lenses restored most of the peripheral vision, although not all at angles to ±10°, and with the lens optimized with aperture smoothing possibly giving better vision than the lens optimized without aperture smoothing at some angles. It is possible to design and manufacture lenses to give near-optimum peripheral visual performance to at least ±30° along one visual field meridian. The benefit of such lenses is likely to be manifest only if a subject has a considerable relative peripheral refraction, for example, of the order of 2 D.