Raytracing in the Compensation of the Peripheral Optics of the Eye

Björn Breidegard, MSc, PhD Student, Jörgen Gustafsson, Optometrist, Bodil Jönsson, PhD, Professor, Bo Möller, LicEng, Sven-Göran Pettersson, PhD


Abstract

Background: Many people with a visual impairment have only peripheral vision. However, there is limited knowledge of the peripheral optics of the eye and only some measurements are available in this field.
Methods: We simulated the paths of peripheral rays through the eye by means of raytracing. Five programs were compared. The OSLO raytracing software proved to be not only the best one in these circumstances but we also found it very well suited to our purpose. Remaining uncertainties are entirely due to a lack of input data about the peripheral part of the optical system of the eye. We designed compensatory optics on the basis of the test results. Results: Lenses have been manufactured in accordance with the calculations made by the program for angles of incidence of 20, 40, and 60 degrees.
The lenses are high compensation astigmatic lenses. The results of perimeter examinations of changes in peripheral vision using attachment optics were inconclusive, while tests of the lenses as attachments in front of a fundus camera produced successful preliminary results. Conclusion: The next step is to test peripheral vision compensatory optics in traffic situations (driving simulator). At the same time attempts are being made to find methods and instruments for measuring the peripheral optics of the eye.

Keywords: astigmatism, central scotoma, raytracing, macula degeneration, peripheral vision.

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