Wittich W, Faubert J, Watanabe DH, Kapusta MA, Overbury O. Spatial judgments in patients with retinitis pigmentosa. Vision Res. 2011;51(1):165-73.
Scientific impact: Retinitis pigmentosa (RP) is a hereditary degenerative disease affecting photo-receptors and causing a progressive loss of vision. Common symptoms are night blindness and loss of peripheral vision. In an interesting twist, analysis of many studies has recently indicated that disease progression is not an indication of patient performance in visual tests. This article explores the possibility that interpretation of spatial and visual signals by the brain is modified to counterbalance visual loss in RP patients. Analysis of these subtle changes could simplify detection of vision loss when compared to conventional tests.
Network contribution: This multidisciplinary study lead by VHRN researchers represents an ideal example of knowledge transfer between fundamental and clinical investigators. It as financed by the VHRN in partnership with the foundation for ocular diseases and the Nazareth and Louis-Braille institute.
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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.