Prism Glasses Expand the View for Patients with ...(ential obstacle or hazard. The patient c...),Health

Prisms by their nature can shift images from one side of the visual field to the other side (e.g., from the right side of the field to the left side). Before Peli's invention, others had tried to develop prism glasses to bring the missing part of the patient's visual field into view. However, these previous techniques placed the prisms in the center of the glasses, which resulted in double vision, which is disturbing and confusing. Peli's solution was to keep the central part prism free and place prisms above and below.

The Archives of Ophthalmology study evaluated the glasses' ability to improve a patient's walking mobility, which includes obstacle avoidance. Forty-three patients were fitted with prism glasses in 15 community-based clinics around the country. The clinicians interviewed them at six weeks and after 12 months. Success was measured by how many patients continued wearing the prism glasses and by their ranking of the prisms' effectiveness in assisting with obstacle avoidance while walking.

Thirty-two participants (74 percent) continued wearing the glasses at week six. At 12 months, 20 (47 percent) were still donning the spectacles eight hours a day and rating them as "very helpful" for obstacle avoidance. These 12-month-plus patients were reporting significant benefits for a variety of obstacle avoidance scenarios (e.g. walking in crowded areas, unfamiliar places, shopping malls). According to Bowers, the first author of the paper, "These results indicate that the glasses have great promise for helping patients resume normal daily life."

Peli partnered with a small optical company in Vermont-Chadwick Optical, Inc. who funded the study in part through a National Institutes for Health (NIH) small business grant. Peli and Karen Keeney, the President of Chadwick Optical, crea
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