Effects of Geometrically Centered and Offset Soft Multifocal Optics on Vision Quality in Myopes

Center-distance multifocal soft contact lenses (CDMFSCLs) correct refractive error. However, their optical center is misaligned due to the temporal decentration of the soft contact lens on eye. This places the optics relatively inferonasal from the visual axis, potentially degrading vision. This study primarily investigated the effects of geometrically-centered optics (GCO) and offset optics (OFO, lens optics positioned over the visual axis) CDMFSCLs on wavefront aberrations in myopic adults. Secondary outcomes included visual performance and subjective ratings.

Thirty-four myopic adults with disease-free eyes participated in a randomized, crossover, double-masked, order-balanced study. All participants were fitted bilaterally with custom GCO and OFO CDMFSCL that shared identical designs, differing only in optic location. The amount and direction of lens decentration from the visual axis were measured using corneal topography maps over a plano GCO CDMFSCL. Wavefront aberrations, visual performance (acuity & contrast sensitivity), and subjective rating were compared between GCO and OFO designs.

All subjects completed the study. On average, GCO lenses displaced temporally (0.56 mm in the right eye, 0.59 mm in the left eye) and superiorly (0.29 mm in the right eye, 0.23 mm in the left eye). After Holm-Bonferroni correction, differences in ocular aberrations and physical discomfort remained statistically significant. However, improvements in contrast sensitivity at the 20/40 line under glare did not reach the adjusted significance threshold.

OFO CDMFSCLs improved optical alignment and reduced wavefront aberrations, but increased spherical aberration. Optimizing optical alignment may enhance visual quality, offering significant implications for lens customization.