Peripheral myopization and visual performance with experimental rigid gas permeable and soft contact lens design

Abstract

Purpose: To evaluate the performance of two experimental contact lenses (CL) designed to induce relativeperipheral myopic defocus in myopic eyes.Methods: Ten right eyes of 10 subjects were fitted with three different CL: a soft experimental lens (Exp-SCL), a rigid gas permeable experimental lens (ExpRGP) and a standard RGP lens made of the same material(StdRGP). Central and peripheral refraction was measured using a Grand Seiko open-field autorefrac-tometer across the central 60◦of the horizontal visual field. Ocular aberrations were measured with aHartman-Shack aberrometer, and monocular contrast sensitivity function (CSF) was measured with aVCTS6500 without and with the three contact lenses.Results: Both experimental lenses were able to increase significantly the relative peripheral myopic defo-cus up to −0.50 D in the nasal field and −1.00 D in the temporal field (p < 0.05). The ExpRGP induceda significantly higher myopic defocus in the temporal field compared to the ExpSCL. ExpSCL inducedsignificantly lower levels of Spherical-like HOA than ExpRGP for the 5 mm pupil size (p < 0.05). Both exper-imental lenses kept CSF within normal limits without any statistically significant change from baseline(p > 0.05).Conclusions: RGP lens design seems to be more effective to induce a significant myopic change in therelative peripheral refractive error. Both lenses preserve a good visual performance. The worsened opticalquality observed in ExpRGP was due to an increased coma-like and spherical-like HOA. However, noimpact on the visual quality as measured by CSF was observed.