Vision testing in the comfort of home

Vision Magazine - December 2020
Mirjam Guesgen

Dennis Graff says that in-home visual field tests are a vast improvement over doing them at the hospital

A UHN-led portable testing tool is providing doctors with a better way to track the progression of glaucoma

Every Saturday morning, Dennis Graff makes himself comfortable in his favourite lounge chair and dons a headset. Although it might look like he's getting ready for a video-gaming session, the 75-year-old Toronto resident is actually testing his vision.

Graff, who previously had surgery to treat both glaucoma and cataracts, is part of a two-year-long study testing the latest tool in eye disease monitoring technology.

"I'm game to help with something that might help others," he says. The system, which consists of a smartphone, a virtual reality headset, a remote clicker and advanced control and analysis software, is the brainchild of Donald K. Johnson Eye Institute scientist Professor Moshe Eizenman. Institute ophthalmologists Drs. Graham Trope and Yvonne Buys assist Prof. Eizenman with patient assessments.

Together, the trio is developing new and better ways to track the progression of the eye disease glaucoma. The innovative tool, called the Toronto Portable Perimeter, or TPP, offers a way for patients in remote parts of Canada, or under-resourced countries around the world, to get access to high-quality vision care.

IMPROVING ON AN IMPERFECT PROCESS

Glaucoma is a disease characterized by the degeneration of the optic nerve connecting the eye to the brain. It progresses slowly, with few symptoms. The best way doctors currently have to track its progression is to ask patients to come to the hospital twice a year for visual field tests. The patient sits in front of a large machine, keeps their eye looking straight ahead and watches lights appearing in their peripheral vision. The patient pushes a button when they see the flashes.

"Patients dislike doing visual field tests. It's one of the most stressful parts of coming to the eye doctor," says Dr. Trope. "It's physiologically unnatural, and a number of patients simply don't do the test well."

Graff says doing the visual field test in the comfort of his own home is a vast improvement over doing them at the hospital.

"The at-home test is just more convenient. I find it more relaxing, too" explains Graff, who has the weekly event marked on his calendar and who has become a bit of a pro when it comes to doing the test at home. "It's very simple."

The TPP system offers more than just convenience. Because the standard, in-office test requires specialized training to administer, there's a cap on the number of patients a hospital can see in a week. That means patients will only have their vision tested twice a year, in many cases, and it's difficult to spot if a person's visual field is deteriorating.

"The evidence indicates that we are missing progression," notes Dr. Trope. The TPP allows patients to do the same test at home, when they want and more often throughout the year. The results of the test are analyzed and sent wirelessly for assessment. It saves patients time, saves money (the TPP is about 40 times cheaper than the standard device) and could allow clinicians to track the disease more efficiently.

So far, the doctors say the results of the study are promising. When the TPP was tested on 150 eyes, it performed just as well as the standard visual field test in terms of measuring how far, and how well, a person can see into their periphery. The TPP was also the clear preference for patients in terms of comfort and ease of use.

With the Toronto Portable Perimeter, Dr. Graham Trope (left) and Prof. Moshe Eizenman hope to increase access to visual field testing

BETTER ACCESS IN MORE PLACES

Lower cost and portability make the TPP perfect for glaucoma screening in remote parts of Canada, where patients might have to travel hours to a hospital. It's also beneficial for under-resourced countries, where patients do not have easy access to hospitals and expensive visual field testing devices.

In 2019, the TPP was sent to northern Ontario, travelling as far as Pickle Lake on-board the CNIB Foundation Eye Van, to screen people in remote communities for glaucoma. The device is also being tested in Singapore and Nepal as a screening tool for the early stages of glaucoma. The TPP has the potential to make a huge impact in developing countries like Nepal, says Prof. Eizenman, because of how frequently glaucoma progresses to blindness through lack of available testing.

"If you detect the disease early and track it, you can manage it," he says.

The team has high ambitions for the device, which they say is part of a bigger move to bring health care out of hospitals and into people's homes.

"It really could revolutionize the way visual fields are performed," says Dr. Trope.