Peripheral Refraction Differences in Myopic Eyes Using Proclear Multifocal Center Distance Contact Lenses with Various Add Power Values
Introduction: The peripheral refractive error of the human eye has been hypothesized to be a major stimulus for the development of its central refractive error. Depending on their power profiles, multifocal center-distance soft contact lenses influence the peripheral refractive error.
Aim: The purpose of this study was to assess refractive profiles across the horizontal visual fields in healthy eyes of young, myopic adults using Proclear multifocal center-distance soft contact lenses in all commercially available add power values and to analyze differences in peripheral refraction.
Subjects and Methods: Using an open-field autorefractor, we measured refractive profiles of 40 adult subjects from 30° nasal to 30° temporal without and with multifocal center distance soft contact lenses with 4 different add power values. We then computed relative refractive errors in power vector notation. We performed statistical analysis to evaluate differences in refractive error profiles induced by the various lenses. In addition we evaluated the clinical relevance of these changes.
Results: Statistically significant differences in defocus were obtained at 20° and 30° of the temporal retinal field. Clinically meaningful values were reached using lenses with 2.00 and 2.50 D add power at 20° and 1.50, 2.00, and 2.50 D add power at 30°. Statistically significant differences in with-the-rule and against-the-rule astigmatism were obtained at 20° and 30° of the temporal retinal field. Clinically meaningful values were reached using lenses with 2.50 D add power. We found no statistically significant differences for oblique astigmatism.
Conclusion: Our findings indicate that significant changes in defocus and with-the-rule and against-the-rule astigmatism at 20° and 30° peripheral refraction in adult myopic eyes can be achieved by using Proclear multifocal center-distance soft contact lenses. These changes are more pronounced for higher add power values, and defocus is affected to a larger extent than with-the-rule and against-the-rule astigmatism. To achieve a clinically meaningful peripheral defocus, add power values of 1.50, 2.00 or 2.50 D should be used.
Keywords: peripheral refraction, refractive error, myopia, multifocal contact lens