Perceptual relevance of abnormal visual field representations: static visual field perimetry in human albinism.
BACKGROUND
In human albinism the plasticity of the visual system is challenged, as part of the temporal retina projects abnormally to the contralateral hemisphere.


OBJECTIVE
To investigate whether the sensitivity of the abnormally projecting temporal retina is preserved.


METHODS
Light spot detection sensitivities were assessed in the central 20 degrees of the visual field in 15 patients with albinism and electrophysiologically determined extent of the retinal projection abnormality, and in 6 controls. The sensitivities were determined monocularly with static white-on-white perimetry using Octopus 101.


RESULTS
In the patients with albinism, the sensitivity of the abnormally projecting part of the temporal retina was not selectively reduced. Apart from the vicinity of the papilla, there was no significant sensitivity difference between nasal and temporal retina in both patients with albinism and controls.


CONCLUSIONS
While in the present study the papilla-induced scotoma was detected in those with albinism tested, there was no indication of a selective visual field defect induced by the projection abnormality. This contrasts with the selective visual field defects observed in some animal models of albinism, and indicates that, in humans, mechanisms of cortical self-organisation make the abnormal representation available for visual perception.
Hoffmann
Michael B
MB
Universitäts-Augenklinik, Visual Processing Lab, Leipziger Street 44, 39120 Magdeburg, UK. michael.hoffmann@medizin.uni-magdeburg.de
Seufert
Petra S
PS
Schmidtborn
Linda C
LC
D000328:Adult; D000368:Aged; D016117:Albinism, Ocular / Q000503:physiopathology*; D005074:Evoked Potentials, Visual; D006801:Humans; D008875:Middle Aged; D009473:Neuronal Plasticity; D012160:Retina / Q000503:physiopathology*; D014792:Visual Acuity; D058609:Visual Field Tests / Q000379:methods; D014794:Visual Fields