Eye for modeling visual distortion in central serous retinopathy.

ABSTRACT

PURPOSE: To present a simple mathematical eye model capable of modeling the metamorphopsia (visual distortion) reported by patients with central serous retinopathy (CSR). METHODS: A computer program was developed to perform the modeling. A simple wide-angle eye model was adapted to include a spherical edema added at the retina. The visual impression was taken as the projection of the retinal pattern back into object space, after the edema had been deflated to its undistorted state. The deflation of the edema was facilitated by assuming a simplified "spreading of photoreceptors" rule. Numerical examples have been included to demonstrate the use of the model. In particular, an Amsler grid was projected to the retina with CSR, to illustrate the associated geometrical distortion. RESULTS: The eye model predicted a pincushion-like distortion of an Amsler grid, that depended (for given height) on the radius of curvature of the CSR. A larger radius of curvature resulted in less pincushion distortion extending over a larger area. CONCLUSIONS: An eye model has been developed that simulates distortion because of CSR. The predicted visual impression of a spherical edema is a pincushion-like distortion. This model may have applications in benchmarking alternate chart designs for detecting CSR, investigating optical aberrations over the edema as well as simulating the visual effect of metamorphopsia in other retinal conditions.