The outer area of the retina, or the peripheral retina, could offer a window into an early detection of Alzheimer's disease long before irreversible brain damage occurs, and a routine eye exam may thus potentially help with an early diagnosis of the neurodegenerative condition, according to a new study.

"The eyes are indeed a window into the brain, but our study reveals that we have been looking at the wrong part of the window. While most clinical eye exams focus on the central retina, the most critical early indicators of Alzheimer's disease (AD) appear to be hidden at the periphery of the eye," author Stephen Wong, from Houston Methodist Hospital in the US, said.