Abstract
Purpose: : There is currently considerable interest in contact lens design that induces relative peripheral myopia, since it is hypothesized that a myopic image on the peripheral retina will inhibit foveal myopia development. This study investigates the effect of several commercially available multifocal contact lenses on peripheral optical errors.
Methods: : A fast scanning Hartmann-Shack wavefront sensor for continuous off-axis data acquisition was used to measure the peripheral optical quality. Wavefront aberrations were measured out to ±40°, sampled in 1° steps, and averaged over four measurements on the right eye of four subjects. Each subject was fitted with a series of soft contact lenses: Bausch & Lomb PureVision® (BL) multifocal high add, low add, and single power; Cooper Vision Proclear® multifocal center near (CN) add +1 D and +2 D; Cooper Vision Proclear® multifocal center distance (CD) add +1 D and +2 D. The subjects were also measured without any contact lens. Spherical refraction was calculated from the second and fourth order Zernike coefficients (Seidel refraction).
Results: : Relative peripheral myopia was induced on all subjects by the CD lens design over the whole visual field, in the order of 0.5-1 D at 20° eccentricity. Conversely, the CN and BL lenses induced a hyperopic shift off-axis. Peripheral coma was worsened by all lens designs. Spherical aberration in the central ±20° was stable for all designs, except for CD where it was higher in the fovea and decreased quadratically with eccentricity. At eccentricities larger than 30°, aberrations increased substantially with lenses, particularly nasally.
Conclusions: : The CD multifocal lens design induces relative peripheral myopia that could prevent myopia development. As expected, the other multifocal and single contact lens designs give hyperopic shifts. However, the increase in higher order aberrations with all lens designs makes the peripheral far point less well-defined.
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