Lack of spatial remapping of the visual field surrounding a monocular scotoma.

BACKGROUND

Changes in cortical receptive fields following deafferentation raise the question of whether interruption of optic nerve fibres engenders spatial distortion in the region bordering the resulting scotoma.

METHODS

The regularity and uniformity of the spatial metric surrounding a monocular Bjerrum scotoma were studied in both the affected and unaffected eyes of a glaucoma patient, using rigorous psychometric measurements and Amsler grid observations.

RESULTS

No expansion of distances towards the edge of the scotoma was found; however, such a change occurs at the border of the normal blind spot, though not binocularly and not in the corresponding field of the other eye.

CONCLUSION

The findings argue against cortical reorganisation following monocular retinal deafferentation in the adult.