The angiographic ocular choroidal crescent: distortion with intraorbital and remote intracranial pathology.

The ocular choroidal plexus can be identified on virtually all normal internal or common carotid angiograms. Posterior flattening of the choroid is often seen with retrobulbar tumors. This angiographic appearance can also be observed in some patients with papilledema and increased intracranial pressure. In these patients, ampulliform dilatation of the dura and subarachnoid space just posterior to the globe produces a retrobulbar mass effect that can mimic true retrobulbar tumor. Enlargement of the ocular choroid crescent is an unusual angiographic finding and can be seen with intraocular expansile lesions such as unilateral axial high myopia with posterior staphyloma. An abnormally small, shrunken choroidal blush can be seen with microphthalmia, extreme degrees of hyperopia, and in the phthisical eye.