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B. Tan, Y.–L. Chen, K. Baker, J.W. L. Lewis, L. Shi, Y. Jiang, M. Wang; Visualization Of Ophthalmic Measurement Using Computer Eye Modeling . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1169.
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© ARVO (1962-2015); The Authors (2016-present)
With the advance of contemporary high–speed computation and optical design software, the practical applications of computer eye modeling include customized designs of intraocular lens, contact lens, and spectacles, prediction of outcomes of laser surgery, and simulation of ophthalmic measurement for medical training purposes. In this presentation, we demonstrate the use of eye modeling to provide the computer simulation of retinoscopic observations.
A commercial optical design software, ZeMax, is used for both the construction of eye models and the simulation of optical measurements. Parameters in the Navarro (1985) schematic eye model are adopted for the emmetropic condition. Ammetropic eye conditions are introduced based on the statistics of refraction (spherical equivalence) dependence on both ocular axial length and cornea radius of curvature. For simplicity, cylindrical condition is induced on anterior cornea surface along specified meridians. In the simulation of retinoscopy, double–pass image analysis is performed under the assumption of perfect diffusive retinal reflection. 100 million rays are traced to produce each image and a 0.5 meter retinoscopic working distance is assumed.
The simulation results successfully reproduce the observation of strip retinoscopy for various refractive conditions. The common "with" and "against" motion appearances for hyperopic and myopic eyes are presented. In addition, the ambiguous "anomalous with motion" in myopia or accommodative eye that often confuses inexperienced users is illustrated. Finally, the limitations of normal and anomalous reflex correlations of myopic condition, slit–beam irradiation, and pupil size that produce such observations are provided.
This computational demonstration of a commonly observed examination shows a promising future of eye modeling in accurately predicting the optical behavior and performance of the eye.
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