Faculty | 6/14/2024

National Clinical Trial Aiming to Improve Vision Rehabilitation

By Jennifer Persons


The clinical trial is evaluating new prism spectacles that expand the visual field for patients who have lost half their field of vision.

Massachusetts College of Pharmacy and Health Sciences (MCPHS) is one of the sites involved in a national clinical trial that aims to help survivors of stroke and other traumatic brain injuries improve their everyday lives.

The Eye and Vision Center on the Worcester Campus is an investigational site where researchers will test a device called a multi-periscopic prism (MPP) lens that, using double reflections of light, shifts objects from the side where the patient has lost vision to the side where they have vision, allowing them to see.

“We’ve never seen any lens that could expand the patients’ field of view as much as this device,” said Kathryn Deliso, OD FAAO. Dr. Deliso is Chief of the Low Vision Service at the Eye and Vision Center. “If this trial is successful, it will change how we treat hemianopia.”

Kathryn Deliso
Dr. Deliso models the multi-periscopic prism (MPP) lens with upper and lower segments.

More than 800,000 Americans suffer from hemianopia, or blindness in one half of the visual field in both eyes. The condition is often caused by a stroke, but it can also occur after other traumatic brain injuries.

Hemianopia affects people of all ages, and there is no cure. Along with losing half their visual field, patients also lose their ability to get around independently and safely. They are unable to drive, and walking in crowded stores, shopping malls, or bus and train stations becomes challenging due to a heightened risk of colliding with other people. This clinical trial is evaluating the safety and effectiveness of the MPP lens, which aims to improve patients’ field of view.

“It could be an exciting and important tool for patients to improve their independence, especially if they’re able to navigate in busy, public, and unfamiliar areas,” Dr. Deliso said.

The trial is in partnership with Schepens Eye Research Institute of Massachusetts Eye and Ear and Harvard Medical School Department of Ophthalmology. Eli Peli, OD, MSc, is the Principal Investigator and inventor of the MPP lens.

The MPP is an upgraded version of the lenses currently used to treat hemianopia, called a Fresnel peripheral prism (FPP). While the FPP expands the visual field by no more than 30 degrees, the MPP can provide up to 45 degrees of expansion.

“We are one of the clinics that will evaluate if the MPP is superior in helping patients avoid colliding with other pedestrians,” Dr. Deliso explained.

Practitioners at the Eye and Vision Center—assisted by School of Optometry students—will fit trial participants with both the FPP and the MPP. The participants will use the devices for several weeks, walking indoors and outdoors to complete their daily activities. Then, their success will be evaluated using a virtual reality environment that will test their ability to detect collisions with other pedestrians.

“Prisms have been the most successful way to treat patients with hemianopia. I’m hopeful this trial will really be beneficial for patients,” Dr. Deliso explained.

A virtual reality environment will test patients' ability to detect collisions with other pedestrians with and without assistance from the MPP.

Since early in her career, Dr. Deliso has worked with low-vision patients, seeing the impact hemianopia can have on their lives. In Massachusetts, patients living with hemianopia are not considered legally blind and are, therefore, not eligible for many critical resources and services.

“I don’t think much of society realizes how functionally impactful losing one half of your vision is,” she said. “I’ll never forget my first patient who was successfully fitted with FPP lenses. Since then, I’ve been focused on making sure hemianopia patients know they’re not being left out and that we are working on more ways to help them function safely, confidently, and independently.”

The trial is funded by the National Eye Institute, which is part of the National Institutes of Health. View the full details about the trial online.