Noninvasive Optical Imaging of the Effects of External Spectral Filters on Macular Autofluorescence in Pseudophakic Eyes

Accumulation of the photoproduct N-retinylidene-n-retinylethaholamine (A2E) within the retina may be associated with the early age-related macular degeneration (AMD). Our biophysical model of retinal photochemistries predicts that as the lens yellows with age a spectral imbalance of the light reaching the retina causes steady-state A2E levels to rise in the RPE, which induces increasing RPE stress leading to AMD progression. If correct, this rise in A2E levels and the initial injury could be prevented by appropriately chosen spectral filtering (e.g., colored sunglasses). Autofluorescence imaging of the retina currently allows noninvasive mapping of total accumulated lipofuscin fluorophores within the macular retinal pigment epithelium (RPE) but not A2E or its precursor alone. By adding new sets of excitation and emission filters to existing fundus cameras and confocal scanning laser ophthalmoscopes, we propose to map individually both A2E and its precursor A2PEH2 or their fractional contributions to the total retinal fluorescence. By following A2E fluorescence in both eyes in subjects following bilateral cataract surgery and intra-ocular lens [IOL] implantation with early symmetric age-related maculopathy who wear our bicolored sunglasses whenever outdoors in the daylight, we propose to test this hypothesis while efficiently controlling for hidden genetic, physiological, and environmental confounding variables between subjects. This pilot protocol seeks to optimize recruitment of suitable subjects and the reproducibility of our spectral imaging and noninvasive analysis of A2E and A2PEH2 levels in the normal and microscopically abnormal regions of the macula. The data from this pilot study will be used to design a clinical study to test our hypothesis.