Related Experiment Video
Updated: Aug 11, 2026
Functional Magnetic Resonance Imaging (fMRI) of the Visual Cortex with Wide-View Retinotopic Stimulation
Published on: December 8, 2023
Visual field expansion in patients with retinitis pigmentosa
Sohel Somani1, Michael H Brent, Samuel N Markowitz
1Low Vision Service, University Health Network Hospitals, Department of Ophthalmology and Vision Sciences, University of Toronto, Tronto, Ont.
Background:
To determine the effectiveness of using spectacle-mounted prisms for field expansion in patients with retinitis pigmentosa (RP).
Methods:
Vision-related activities of daily living (V-ADL) questionnaire scores and functional visual field score (FFS) measurements were conducted before and after a one-month trial of spectacle-mounted prisms in those patients with RP who had residual central visual fields of less than 10 degrees.
Results:
16 patients were recruited who met study inclusion criteria. Mean V-ADL and FFS at baseline were 67.6 (73%) and 22.9 (46%), respectively. After a 1-month trial using spectacle-mounted prisms, V-ADL and FFS demonstrated significant improvement to 73.4 (80%, p < 0.05) and 27.0 (54%, p < 0.001), respectively.
Interpretation:
Spectacle-mounted prisms effectively create visual field expansion and noticeable spatial orientation benefits in patients with RP. This may provide an adjunctive tool in low vision rehabilitation and should be considered in all cases with RP with less than 10 degrees of visual field.
