THE ROLE OF TRANSCRANIAL DOPPLER IN NONARTERITIC ISCHEMIC OPTIC NEUROPATHY

PURPOSE: To investigate through the use of cerebral Doppler technology whether emboli are a more common cause of nonarteritic anterior ische mic optic neuropathy (NAION) than previously recognized. METHODS: Elev en patients with a recent (<121 days) history of nonarteritic anterior ischemic optic neuropathy and 10 age-matched controls (event >121 day s) were examined using a Nicolet Pioneer 2020 transcranial Doppler (TC D) unit with a 2-MHz bilateral continuous monitoring capability. The r ight and left middle cerebral arteries were evaluated simultaneously f or 30 minutes at a depth of 50 to 55 mm, and the number of emboli, blo od flow velocities, and pulsatility indices were recorded. Data were s tored by computer, and hard-copy color recordings were made. RESULTS: None of 11 patients with a recent history of NAION demonstrated microe mboli by TCD examination. One patient in the control group who had a r emote history of NAION had a microembolic event rate of 12 per hour (s ix over 30 minutes). This patient had a history of prosthetic cardiac valve replacement and was taking anticoagulation medication at the tim e of the examination. CONCLUSIONS: Our study did not reveal an increas ed incidence of embolic events in patients with NAION when they were e xamined in a transcranial Doppler study of the middle cerebral arterie s. This study does not support embolism as a frequent cause of NAION. (Am J Ophthalmol 1998;126:288-290. (C) 1998 by Elsevier Science Inc. A ll rights reserved.).