A method for differentiating ocular higher-order aberrations and light scatter as applied to retinitis pigmentosa

Purpose. The purpose of this study is to report a method for differentiating ocular higher-order aberrations and intraocular light scatter based on a deconvolution technique. Methods. An optical system was used to image a laser slit on the retina and also to perform Shack-Hartmann wavefront sensing. From the laser slit image, the line spread function, incorporating both ocular higher-order aberrations and light scatter, was derived. The laser slit image was deconvolved with a point spread function obtained from the Shack-Hartmann image. The area under the line spread function that was derived from the laser slit image after deconvolution provided a measurement of intraocular light scatter. The deconvolution technique was applied to images obtained in a group of 13 patients (mean age +/- I standard deviation: 42 +/- 12 years) with retinitis pigmentosa (RP), a retinal disease in which, by clinical examination, changes in the lens of the eye can be manifested. Measurements were compared with those obtained from 20 visually normal control subjects (mean age +/- 1 standard deviation: 43 +/- 17 years). Results. Combined higher-order aberrations and light scatter, measured as the area under the line spread function derived from the laser slit image, were increased significantly in the patients with RP as compared with the control subjects (p = 0.004). Ocular higher-order aberrations obtained from the Shack-Hartmann images were higher in the patients with RP than in the control subjects (p = 0.05). Intraocular light scatter derived from the deconvolved laser slit image was significantly higher in the patients with RP than in the control subjects (p = 0.009). Minimizing the contribution of ocular higher-order aberrations by deconvolution reduced the area under the line spread function in the control subjects and patients with RP, denoting an improvement in retinal image quality. Conclusions. A method for differentiating ocular higher-order aberrations and intraocular light scatter based on deconvolution was developed that may be useful for determining the level of improvement in retinal image quality that can be anticipated by the application of adaptive optics to aging and diseased human eyes.