Epilepsy surgery provides new insights in retinotopic organization of optic radiations. A systematic review.

PURPOSE OF REVIEW: Visual field defects (VFDs) produced by temporal lobe resections provide valuable information on the retinotopic organization of the optic radiations. The results of this systematic review of the literature will be translated into a revised--and evidence-based--map of the retinotopic anatomy of the anterior optic radiations.

RECENT FINDINGS: Recent studies provide best evidence by combining automatic static perimetry and modern imaging techniques. VFDs occur in 83% of patients undergoing temporal lobectomy. There is a significant correlation between size of resection and amount of VFD. Most defects appear incongruous. Macular involvement is seen in more than 50% of cases. The inferolateral defect border is of a sloping nature and sometimes crosses the horizontal meridian. On the basis of these findings, the classical theory on the retinotopic anatomy of the optic radiation should be revised.

SUMMARY: This article systematically reviews the literature on VFDs after temporal lobe resection. Frequency, size, congruity, macular involvement and defect borders are related to size of resection. The classical theory on the retinotopic organization of the anterior optic radiations should be revised.