Latricia Pack


PURPOSE: The Frequency 55 soft contact lens (CooperVision, Inc.) is available in an aspheric and spheric lens design. The aspheric lens is designed to decrease spherical aberration and provide better vision, especially for patients with low astigmatism. We investigated this claim by comparing visual and optical performance of the two designs.

METHODS: Twenty-five myopic subjects (sphere-1.00 to-10.00D; cylinder 0.00 to-1.00D) were recruited for a double-blind, prospective study in which one eye was fitted with the aspheric and spheric lens in random order. We evaluated vision with the best spectacle correction and with each lens using contrast sensitivity (VectorVision chart). Optical quality was tested without correction and with each lens on the eye using a clinical Shack-Hartmann aberrometer (Complete Ophthalmic Analysis System by WaveFront Sciences, Inc.). Wavefront analysis was based on a 4mm pupil. Further analysis will be done for larger pupil sizes.

RESULTS: There was no statistically significant difference for the group as a whole in contrast sensitivity, residual RMS wavefront error, or higher-order residual RMS wavefront error for the aspheric vs. spheric lens. However, around half of the subjects had better visual and optical performance with either lens. Among those subjects, about half performed better with the aspheric design and half with the spheric design. Among patients who saw better with the aspheric design, the lens provided better correction of astigmatism. The aspheric lens did not always provide a better correction of either spherical aberration or higher order aberrations; in some cases it over-corrected spherical aberration.

CONCLUSIONS: The aspheric design provides superior optics and vision in some, but not all, patients. Availability of an aspheric design gives doctors more options for correcting vision and may be especially beneficial for patients with low astigmatism. Evaluation with trial contact lenses is recommended to verify that the patient will benefit from the aspheric option.


Year: 2002

Program Number: Poster 42

Resource Type: Scientific Program

Author Affiliation: n/a

Co-Authors: Sarah Ross, Latricia Pack, Thomas Salmon, Richard Hoenes

Co-Author Affiliation: Northeastern State University, Oklahoma College of Optometry, Northeastern State University, Oklahoma College of Optometry, Northeastern State University, Oklahoma College of Optometry, Northeastern State University, Oklahoma College of Optometry

Room: n/a