A novel clinical sign in macular telangiectasia type 2.

The objective of the study is to report, and propose a hypothesis for, a novel clinical sign in patients with macular telangiectasia type 2. Nine consecutive patients with macular telangiectasia and visible parafoveal graying were examined. The parafoveal graying decreased in intensity with continuous light exposure from an indirect ophthalmoscope. After dark adaptation for 15 minutes, the intensity of parafoveal graying increased again. This phenomenon appears to be a novel and global sign in patients with macular telangiectasia type 2. It could be a possible photochemical reaction occurring due to the release of chromophores from the abnormal Müller cells.