Early test warns of world's leading eye disease

September 23, 2013, The ARC Centre of Excellence in Vision Science

(Medical Xpress)—A new, quick and simple eye test can predict who is more at risk of age-related macular degeneration (AMD), a leading cause of blindness worldwide.

Researchers at Australia's Vision Centre (VC) have found that while people with early AMD can still see in fine detail, other parts of their vision may be damaged and this isn't revealed by current tests.

The new test, by revealing the damage, can show doctors or optometrists where to look and when to watch a patient more closely, helping them to lessen the risk of the disease and avoid total blindness.

"Many people as they grow older have little yellow blobs of protein and lipids that build up in the retina, known as drusen," says Professor Ted Maddess of The VC and The Australian National University (ANU). "While having drusen doesn't always lead to AMD, it can signal an increase in the individual's risk of the eye disease."

Prof. Maddess explains that AMD occurs when the drusen accumulate and expand, blocking the retina from getting oxygen or from disposing dead eye cell or tissue. This causes patches of the retina to die or leads to of blood vessels in the eye.

"It ends up damaging our central vision, which we use to read, drive and see in fine detail. This is why current tests for AMD focus on the central visual field," he says. "However, these tests ignore other parts of the retina, which our study now shows can be damaged in early AMD."

Using the TrueField Analyzer, a device developed by Prof. Maddess's team and the Australian company "Seeing Machines", Vision Centre researchers tested how pupils of early AMD respond to images on LCD screens. The images were provided to each eye at 44 locations in the person's visual field.

Two video cameras using infrared lighting recorded the instantaneous response of the pupils, which was then analysed by a computer.

"All the patients had drusen and most could see in fine detail, which means that their central vision was still working well," Prof. Maddess says. "However, when we measured other parts of their vision, we found that their pupils responded less compared to people without AMD.

"This shows that some of the drusen were harming parts of their vision, and the test reveals which patches were causing the damage."

"While we don't know if damage caused by drusen will always result in AMD, the test can act as a warning sign for doctors and patients," Prof. Maddess says. "For instance, if there's a patch of drusen near the central vision, and if the person's vision is damaged in the same area, it's a sign that they need close attention.

"Doctors can advise the patient to exercise more, to eat more antioxidants, or to stop habits like smoking that cause eye disease. They can also have the patient come in more frequently for check-ups."

Prof. Maddess says AMD currently affects one in seven Australians over the age of 50, costs $2.6 billion a year, and will rob the central vision of 1.77 million Australians by 2030. In developed countries about 15 per cent of people over 40 show signs of early AMD, with about four per cent progressing to late stage AMD each year. "By the time eye tests detect damage in the , it's usually too late because it means the disease has progressed too far.

"Knowing who is at risk of progressing to late stage AMD and helping them to prevent it, regardless of whether they develop the disease or not, can go a long way towards saving their sight."

The study "Multifocal pupillography identifies retinal dysfunction in early AMD" by Faran Sabeti, Andrew C. James, Rohan W. Essex and Ted Maddess was published in Graefe's Archive for Clinical and Experimental Ophthalmology.

Explore further: New, easy test for age-related macular degeneration

More information: DOI: 10.1007/s00417-013-2273-z

Related Stories

New, easy test for age-related macular degeneration

October 9, 2012
(Medical Xpress)—Scientists from Australia's Vision Centre have demonstrated a quick, accurate test under lights for one of the world's leading causes of blindness.

Impaired autophagy associated with age-related macular degeneration

August 21, 2013
A new study published in the prestigious PLoS One journal changes our understanding of the pathogenesis of age-related macular degeneration (AMD). The researchers found that degenerative changes and loss of vision are caused ...

Researchers find better way to save sight

March 15, 2012
People who are losing their eyesight through aged-related macular degeneration (AMD) may soon be able to find out if a commonly used drug can help save their vision.

Faster help for stroke victims

January 4, 2013
Scientists have developed a quick, easy and cheap vision test to find out which part – and how much – of the brain of a stroke victim has been damaged, potentially enabling them to save more lives.

Researchers report a critical role for the complement system in early macular degeneration

August 15, 2013
In a study published on line this week in the journal Human Molecular Genetics, Drs. Donita Garland, Rosario Fernandez-Godino, and Eric Pierce of the Ocular Genomics Institute at the Massachusetts Eye and Ear, Harvard Medical ...

VCU Medical Center first in Virginia to implant telescope for macular degeneration

April 15, 2013
Physicians at the Virginia Commonwealth University Medical Center have become the first in Virginia to successfully implant a telescope in a patient's eye to treat macular degeneration.

Recommended for you

Study advances gene therapy for glaucoma

January 16, 2018
While testing genes to treat glaucoma by reducing pressure inside the eye, University of Wisconsin-Madison scientists stumbled onto a problem: They had trouble getting efficient gene delivery to the cells that act like drains ...

New study offers added hope for patients awaiting corneal transplants

January 9, 2018
New national research led by Jonathan Lass of Case Western Reserve University School of Medicine has found that corneal donor tissue can be safely stored for 11 days before transplantation surgery to correct eye problems ...

Diabetic blindness caused and reversed "trapped" immune cells in rodent retinas

January 3, 2018
Johns Hopkins researchers have discovered a cell signaling pathway in mice that triggers vision loss in patients with diabetic retinopathy and retinal vein occlusion – diseases characterized by the closure of blood vessels ...

Ophthalmologists increasingly dissatisfied with electronic health records

December 29, 2017
Ophthalmologists' use of electronic health records (EHR) systems for storing and accessing patients' medical histories more than doubled between 2006 and 2016, while their perceptions of financial and clinical productivity ...

Higher omega-3 fatty acid intake tied to lower glaucoma risk

December 26, 2017
(HealthDay)—Increased daily intake of ω-3 fatty acids is associated with lower odds of glaucoma, but higher levels of total polyunsaturated fatty acid (PUFA) intake are associated with higher odds of developing glaucoma, ...

Protein analysis allows for treatment of eye-disease symptoms with existing drugs

December 21, 2017
Demonstrating the potential of precision health, a team led by a researcher at the Stanford University School of Medicine has matched existing drugs to errant proteins expressed by patients with a rare eye disease.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.