Scientists develop easier test for blindness

People affected with age-related macular degeneration (AMD) will often notice a blank patch or dark spot in the centre of their sight. Photo: Special Arrangement

Scientists claim to have developed a quick and accurate test for one of the world’s leading causes of blindness.

Researchers from Australia’s Vision Centre demonstrated the test under lights for age-related macular degeneration (AMD) - one of the world’s leading causes of blindness.

A new study shows that age-related macular degeneration (AMD) can be just as effectively and more rapidly and inexpensively diagnosed under bright lights, instead of requiring patients to sit for 20 minutes in a darkened room.

“AMD accounts for half of the legal blindness cases in Australia,” says Professor Ted Maddess from The Vision Centre and The Australian National University.

“It affects one in seven people over the age of 50, costing the nation $2.6 billion a year. Globally, it affects 25 to 30 million people, with an annual cost of $343 billion.

“While current tests for AMD are done in the light, scientists have proposed that it might be better if the patient has their vision adapted to the dark prior to the test,” he said in a statement.

“This is because they had found that rod receptors - vision cells that we use to see in black and white and in low light - die earlier in AMD than the cone receptors we use to see in colour during the day. So it had been suggested that AMD tests would be more accurate if they were based on the health of a person’s rods,” researchers said.

Recent research, however, has shown that the eye’s cones, while dying later than rods, start to deteriorate at the same time as the ‘night vision’ cells.

Using the TrueField Analyser, researchers tested how pupils respond to images on LCD screens.

“We found little to no difference in the results - with the TrueField Analyser, we could diagnose AMD just as well regardless of how much light the eyes were exposed to during the test.

“Our research indicates that it’s not necessary for people to be dark-adapted, which eliminates any long waiting periods and the need for dark rooms. So it is an easier test than was previously thought,” researchers said.