The peripheral prism glasses were invented by Dr. Eli Peli, a senior scientist at the Schepens Eye Research Institute in Boston and a professor of ophthalmology at Harvard Medical School.

Hemianopia results from damage to the optic pathways in the brain. A patient with the condition might be unaware of what he or she cannot see and frequently bumps into walls and people, or trips over objects on the side where the visual field is missing.

Peli expanded the visual field by attaching small, specially designed high power prisms on the top and bottom of one spectacle lens, leaving the center of the lens untouched. The prisms pull in images missing from the visual field on the side of the vision loss, alerting the patient to the presence of a potential obstacle or hazard.

Peli partnered with a Vermont optical company -- Chadwick Optical Inc. -- which funded the study.

The research that included Dr. Alex Bowers and Karen Keeney, president of Chadwick Optical, appears in the journal Archives of Ophthalmology.