Jagdish M. Jethmalani

Wavefront-guided spectacle lenses

A new type of spectacle lens was developed incorporating a thin layer of a novel polymer with a light-programmable refractive index. The refractive index change can be used to change the optical power of the lens. One of the applications of this new lens is the correction of high-order aberrations of the human eye. A feasibility study was conducted to determine whether such wavefront-guided high-order correcting spectacle lenses can be 1) accurately manufactured, and 2) improve vision of human subjects. The ocular wavefront of 30 subjects was measured with a Z-ViewTM diffractive aberrometer. A vision correcting high-order zone canceling the subjects ocular wavefront was programmed directly into pairs of wavefront-guided spectacle lenses (WFGSL). The lenses could be successfully manufactured to an average Zernike rms accuracy of 81% (range 70% to 90%). Comparison was made against identical spectacles without the high-order zone. Double-masked vision tests included high and low-contrast visual acuity, and contrast sensitivity. The subject was allowed only a few minutes of adaptation time to the spectacles. While some experienced a dramatic improvement in vision, this was not observed for all subjects, in particular for subjects with small amounts of high-order aberrations. We speculate that more consistent vision improvement can be achieved by 1) determining a subjects candidacy for WFGSL based on the subjects ocular aberrations, 2) correcting only selected aberrations, 3) manufacture with higher purity and accuracy, and 4) lengthening the adaptation period before testing each lens.

Programmable Wavefront Control with Photopolymers

By controlling the photocuring of polymer systems between optical substrates it is possible to accurately program a wide variety of wavefront patterns. Two distinct methods are described, and examples of programmed wavefront elements are presented.