Objectives  Many retinal conditions have been associated with strokes, and patients with unilateral hemisphere stroke may experience a horizontal conjugate eye deviation. This study examined the visual function after the MCA occlusion.
Methods  The distal MCA of the right hemisphere was directly occluded in mice and the ischemic areas were assessed histologically. To evaluate visual functions of ischemic mice, optomotor responses, electroretinogram（ERG） and Flash Visual Evoked Potential (FVEP) were measured. The histological change of eyes was measured by HE staining. Transgenic Thy1-YFP mice were used to determine how MCA occlusion affects efferent projection neurons in layer V and ganglion cells in retina.
Results  We observed that neurons in layer V of Thy1-YFP mice disappeared in parts of motor cortex, somatosensory cortex, but not in visual cortex. The visual function of the contralateral eye, which projects to the lesioned hemisphere, was normal following MCAo. No significant difference could be seen in the ERG and HE staining results of bilateral eyes. However, the optomotor response of the ipsilateral eye was reduced and significantly lower in ischemic mice than those in sham-operated mice. The latencies of FVEP increased in the monocular visual cortex of the ischemic hemisphere.
Conclusions  The results show that focal cerebral ischemia produces ipsilateral visual disturbances and the propagation of visual signals to the cortex was inhibited in the ipsilateral hemisphere.in mice. It provide a platform for further investigation of mechanisms of visual function affected by cortical ischemia.