Powerful technique helps pupils reveal diseases

SYDNEY - A powerful new technique, developed by scientists, can quantify damage caused by serious eye diseases affecting tens of millions worldwide.

Known as multifocal pupillography, the method involves monitoring minute responses of the eye's pupil to light signals in different parts of the patient's visual field.

ARC Vision Centre and Australian National University (ANU) researchers led by Ted Maddess and Andrew James are pioneering the use of multifocal pupillography for painless detection and monitoring of glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy.

AMD is a progressive disease of the retina wherein the light-sensing cells in the central area of vision (the macula) stop working and eventually die. Together these are thought to affect around 100 million people globally, aged 50 and over.

The technique relies on a feedback loop of nerve signals, which flow from each eye to the brain and back again to both pupils of the eyes by a secondary pathway, Maddess explains.

We've known for a century or so that the pupil reacts more to a stimulus on one side of the visual field than the other, though we did not know how or why until recently, he said.

In our research we have been trying to localise the responses of the pupil to particular places across the visual field and hence, the eye's retina, said Maddes, according to a release of the Vision Centre.

By mapping places where the response of the retina is patchy and the pupil responds less strongly, the team has been able to detect portions of the retina affected by the disease and so improve the chances of early accurate diagnosis and treatment of a condition which in many cases may result in loss of vision or complete blindness.


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