The authors present a retrospective records review, using the search terms homonymous hemianopia, visual field loss and MRI. Only posterior circulation artery territory ischemic strokes were included. Demographics, stroke details and initial and follow-up with 24-2 SITA Standard perimetry results were extracted. Two authors independently interpreted the perimetry results. The extent of the lesion was assessed using sagittal images from MRI. A total of 92 patients were included in the analysis. Six patients were excluded due to unreliable or uninterpretable perimetry results. The patients were divided into three groups depending on anteroposterior extent of the lesion; 1) involved visual cortex only, 2) extended to include posterior optic radiations and 3) extended to include anterior optic radiations. The lesion extent was then correlated with the perimetry results. The authors report 96% of visual field loss in one hemifield accurately predicted the laterality of the ischemic lesion, however in cases of bilateral visual field loss 33% lesions were only found in one hemisphere. This highlights MRI has a lack of sensitivity which has the potential to be clinically significant. Quadrantanopia evaluation accurately located the visual cortex quadrant in 97% of cases. A limitation of the study was the use of the 24-2 programme which limits detection of visual field loss as a result of lesions in the anterior visual cortex. This study shows the reliability of patterns of visual field loss predicting ischemic lesion location. However, it also highlights limitations with MRI and the 24-2 programme in this group of patients.
Predicting ischemic lesion location using perimetry
Reviewed by Lauren Hepworth
Accuracy of visual fields in localizing MRI lesions in posterior cerebral artery infarction.
CONTRIBUTOR
Lauren R Hepworth
University of Liverpool; Honorary Stroke Specialist Clinical Orthoptist, Northern Care Alliance NHS Foundation Trust; St Helen’s and Knowsley NHS Foundation Trust, UK.
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