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

Area of Science:

• Ophthalmology and Optometry
• Optical Engineering
• Vision Science

Background:

• Center-distance multifocal soft contact lenses (CDMFSCLs) correct refractive errors but often suffer from optical misalignment.
• Temporal decentration of CDMFSCLs shifts optics inferonasally to the visual axis, potentially compromising visual performance.
• Understanding the impact of optic placement is crucial for optimizing multifocal contact lens design.

Purpose of the Study:

• To investigate the effects of geometrically-centered optics (GCO) versus offset optics (OFO) in CDMFSCLs on wavefront aberrations.
• To compare visual performance and subjective ratings between GCO and OFO CDMFSCL designs in myopic adults.
• To evaluate the impact of precise optical alignment on vision quality with multifocal contact lenses.

Main Methods:

• A randomized, crossover, double-masked study involving 34 myopic adults fitted bilaterally with custom GCO and OFO CDMFSCLs.
• Lens decentration measured using corneal topography; wavefront aberrations, visual acuity, and contrast sensitivity compared between designs.
• Custom lenses shared identical designs, differing solely in optic location relative to the visual axis.

Main Results:

• GCO lenses exhibited significant temporal and superior decentration from the visual axis in both eyes.
• OFO CDMFSCLs demonstrated statistically significant reductions in ocular aberrations and improved physical comfort compared to GCO.
• While contrast sensitivity showed improvement under glare with OFO, it did not reach statistical significance after correction.

Conclusions:

• Offset optics (OFO) in CDMFSCLs enhance optical alignment and reduce wavefront aberrations, though they increase spherical aberration.
• Optimizing optical alignment through lens design can significantly improve visual quality in multifocal contact lens wearers.
• These findings have important implications for the customization of soft multifocal contact lenses for myopia management.