Glowing picture of health

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Lipofuscin is a normal by-product of photoreceptor metabolism. When photoreceptor discs are processed by lysosomes, a small amount of lipofuscin remains and accumulates in retinal pigment epithelium (RPE) cells. Lipofuscin accumulates with age and in the over-70-year-old eye it is estimated that 20-30 per cent of the cytoplasmic space is taken up by lipofuscin and melanolipofuscin (a combination with melanin). Extracellular accumulation of this debris constitutes drusen which, once large enough, lead to denaturation and depigmentation of overlying retinal pigment epithelium and so revealing the discrete yellow lesions familiar during ophthalmoscopy.