Spatial judgments in patients with retinitis pigmentosa

Previous investigations into cortical plasticity in the presence of ocular disease have focused on central retinal damage. Perceptually, patients often report distortions of visual space which can be partially explained by perceptual filling-in. The mechanisms involved could also apply to peripheral field loss. Spatial interval discrimination was tested in 28 retinitis pigmentosa (RP) patients and a control group. When stimuli were presented to both hemispheres, bias did not differ whereas threshold was poorer in RP patients. When presenting the task to only one hemifield, bias was related to field asymmetry, but only in the left visual field, r2 = .59. Brain laterality may be an important factor when examining changes in cortical function in response to peripheral system damage.

Research highlights
► Spatial vision accuracy in patients with RP field loss is similar to normals.
► Their spatial vision precision contains more uncertainty than normals.
► The left visual field showed a systematic relationship to field asymmetry in RP patients.
► Brain laterality may influence adaptations to adult-onset visual field loss.