The investigators will develop and test different configurations of high-power prisms to expand the field of vision of patients with visual field loss to assist them with obstacle detection when walking. The study will involve multiple visits (typically four) to Schepens Eye Research Institute for fitting and testing with the prism glasses. The overall objective is to determine best designs and fitting parameters for implementation in prism devices for future clinical trials.
Visual field loss, either peripheral field loss or hemianopic field loss
Visual acuity of at least 20/50 in the better eye
In sufficiently good health to be able to complete sessions lasting 2-4 hours
Able to independently walk short distances
Any physical or mental impairments, including cognitive dysfunction, balance problems or other deficits that could impair the ability to walk or use the prism spectacles
A history of seizures in the last 6 months
Hemispatial neglect (subjects with hemianopic field loss only)
Single group
High power prisms
DeviceHigh power prisms designed to shift images from blind areas into portions of the wearer's remaining, seeing, field of vision
Field of view expansion
Horizontal and vertical extent of the expansion (in degrees) of the field of view
Pedestrian detection rate
Proportion of pedestrians detected (in simulated walking or simulated driving)
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Massachusetts Eye and Ear Infirmary
Lead sponsor
National Eye Institute (NEI)
Collaborator
