HIGHLY CURVED SPECTACLE LENSES ARE SUPERIOR TO CONVENTIONAL ‘CORRECTED CURVE’ DESIGNS

Michael Morris

Abstract

PURPOSE. The performance of highly curved spectacle lenses that are nearly concentric about the center of rotation of the eye were compared with traditional ‘corrected curve’ designs using optical raytracing and clinical measures. METHOD. A series of highly curved spectacle lenses covering prescriptions ranging from +2.00 to-6.00 diopters was designed based upon a single front surface with radius of curvature of 33 mm and central thickness of 1.8 mm. The optical performance of the new lens series was compared by optical raytracing with the performance of traditional shape spherical and aspheric lenses of equivalent back vertex power for a number of measures including: defocus, distortion, transverse chromatic aberration, and prismatic effect. In addition, the lenses were manufactured and mounted in spectacle frames and compared with conventional form spectacles of equivalent eye size to evaluate field of view by means of a kinetic perimetry task.

RESULTS. The highly curved lens series had equivalent or superior off-axis resolution performance compared with the conventional curves, and significantly reduced transverse chromatic aberration, distortion and prismatic effect. In addition, the results among wearers of the lenses indicate that the field of view through highly curved lenses is substantially greater than with traditional curves due to the backward sweep of the lenses.

CONCLUSIONS. Spectacles based upon highly curved lenses offer superior performance to that obtained with traditional curves. Implications of highly curved lens designs will be discussed with respect to frame design and wearer acceptance.

Details

Year: 2001

Program Number: Poster 114

Author Affiliation: SOLA International, Inc.

Co-Authors: Scott Fisher

Co-Author Affiliation: SOLA International Research

Room: Exhibit Hall C