Vision testing in the comfort of home
Dennis Graff
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.


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.

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