Macula Sparing, Macula Splitting
Macula sparing is a feature of an homonymous hemianopia in which central vision is intact, due to damage confined to the occipital cortex without involving the occipital pole. This may occur because anastomoses between the middle and posterior cerebral arteries maintain that part of area 17 necessary for central vision after occlusion of the posterior cerebral artery.
Cortical blindness due to bilateral (sequential or simultaneous) posterior cerebral artery occlusion may leave a small central field around the fixation point intact, also known as macula sparing.
Macula splitting, an homonymous hemianopia which cuts through the vertical meridian of the macula, occurs with lesions of the optic radiation.