Scientists develop easier test for blindness

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 thehealth of a person's rods," researchers said.
Recent research, however, has shown thatthe eye's cones, while dying
later than rods, start to deteriorate at thesame time as the 'night
vision' cells.
Using the TrueField Analyser, researchers tested how pupils respond to
images on LCDscreens.
"We found little to no difference in the results - with the TrueField
Analyser, we could diagnose AMD just as wellregardless of how much
light the eyes were exposed to during the test.
"Our research indicates that it's not necessary forpeople 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.

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