Researchers unravelling the complex aetiology of AMD

Researchers are making steady progress in unlocking the mysteries of the complex combination of factors underling the aetiology of age-related macular degeneration (AMD), according to Chi-Chao Chan M.D.

“AMD aetiology involves multiple factors such as ageing, genetic predisposition, environmental elements such as smoking and diet, lipid metabolism, cell death, oxidative stress and inflammation,” she said. “From this perspective, AMD can be viewed as producing dysregulation and dysfunction of homeostatic processes that change throughout ageing,” she added

She noted that AMD was first described as “symmetrical central chorioretinal disease occurring in senile persons” by Hutchinson and Tay in 1875 and remains the leading cause of irreversible vision loss and blindness in the developed world among the elderly.

Discussing the pathology of AMD, Dr Chan said that during the natural ageing process, a few small drusen and RPE pigmentary degeneration can be seen in the periphery. Thickened Bruch’s membrane and internal limiting membrane as well as accumulation of lipofuscin granules in RPE are often found in ageing macula.

“AMD pathology is characterised by soft drusen, degenerative changes and atrophy of the photoreceptors, RPE, Bruch’s membrane and choriocapillaries in the macula,” she said.

A wide spectrum of pathological abnormalities is found to increase as AMD progresses, said Dr Chan. She said that para-inflammation exists in the ageing retina under physiological conditions and also plays a role in age-related diseases including AMD.

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