Influence of contact lens power profile on peripheral refractive error

To measure the power profile across the optic zone (OZ) of four commercially available soft contact lenses and establish the impact on the peripheral refractive error of the eye.The power profiles of a spherical conventional hydrogel contact lens (etafilcon A, JJ Vistakon, Jacksonville, FL USA) and three spherical silicone hydrogel contact lenses (lotrafilcon A and B, CIBA Vision, Duluth, GA USA; enfilcon A, CooperVision, Pleasanton, CA USA) with a labeled power of -3.00 and -6.00 diopters were measured using a Shack-Hartmann wavefront sensor power mapping device. Central and peripheral refraction across the horizontal meridian (nasal and temporal visual field at 20, 30, and 40 degrees) was measured with an open-field autorefractor (Shin Nippon NVision K5001, Osaka Japan) with and without contact lenses in 26 myopic subjects. The relative peripheral refractive error on the eye was estimated and compared with and without contact lenses and between contact lenses.Differences in the distribution of the power profile across the OZ were apparent between contact lens types and powers. No significant differences (p0.05) were found between contact lens types for their effect on on-axis refraction. Significant differences (p0.05) were found at all peripheral retinal eccentricities between contact lens types.For a given central power, the four contact lenses exhibited variations in optical power across the OZ of the lens. The distribution of optical power across the OZ has an influence on the peripheral refractive error of the eye.