Schematic eye models for simulation of patient visual performance

PURPOSE: To determine if model eyes can simulate the visual performance of normal human eyes under conditions of varying low myopic blur, pupil size, and contrast. METHODS: High and low contrast Bailey-Lovie logMAR visual acuity (VA) of th ree normal eyes of three subjects were measured for four artificial pupil s izes and ten levels of myopic defocus, Simulated visual acuities were then determined for three model eyes-the Indiana Eye with no spherical. aberrati on, the Indiana Eye with average spherical aberration, and the Kooijman Eye -by generating optically aberrated VA charts for each testing condition usi ng Visual Optics Lab software by Sar ver and Associates, Inc, and having th e subjects read high resolution printouts of these charts using a 3-mm pupi l and optimal spectacle correction. The correlation between real VA and sim ulated VA was then plotted and a regression line calculated. RESULTS: Slopes for the Indiana Eye, Indiana Eye with spherical aberration, and Kooijman Eye were 0.98, 0.98, and 1.01 for high contrast, and 0.92, 0. 67, and 0.75 for low contrast, respectively. The r(2) values were 0.73, 0.7 4, and 0.77, for high contrast, and 0.69, 0.40, and 0.50 for low contrast, respectively. Under low contrast conditions the Indiana Eye VA was signific antly closer to the real VA than that of the other two models (P < .0003). CONCLUSION: Visual performance can be simulated by eye models. The simple s ingle surface Indiana Eye with no spherical aberration best modeled both hi gh and low contrast visual acuity.