Title: Multispectral Fundus Imaging: Acquisition, Interpretation Using Computer Simulations, and Potential Clinical Applications Grant Number Gr/s09906/01 2. Advantage West Midlands Grant Number Bgin3264

Purpose To develop a non-invasive method for quantification of blood and pigment distributions across the posterior pole of the fundus from multispectral images using a computer generated reflectance model of the fundus. Methods A computer model was developed to simulate light interaction with the fundus at different wavelengths. The distribution of macular pigment and retinal haemoglobins in the fundus was obtained by comparing the model predictions to multispectral image data at each pixel. Fundus images were acquired from 31 subjects from various ethnic backgrounds and parametric maps showing the distribution of Macular Pigment and of retinal haemoglobins throughout the fundus were computed. Results The relative distributions of macular pigment and retinal haemoglobins in the subjects were successfully derived from multispectral images acquired at wavelengths 507, 525, 552, 585, 596 and 611nm. Comparisons of model and image data show that both display similar trends, although model predictions overestimate the tissue reflectance at higher wavelengths. Successful application of the technique is contingent upon minimal eye movement between exposures. Conclusion The distributions of macular pigment and retinal haemoglobins obtained in this preliminary investigation are in good agreement with published data on normal subjects. The ongoing development of the imaging system should 3 allow for absolute parameter values to be computed. A further study will investigate subjects with known pathologies to determine the effectiveness of the method as a screening and diagnostic tool.