Axonal loss in a patient with anterior ischemic optic neuropathy as measured with scanning laser polarimetry

PURPOSE: To report Nerve Fiber Analyzer (NFA/GDx; Laser Diagnostic Technologies, San Diego, California) measurements in a patient during the early phase of an anterior ischemic optic neuropathy.

METHODS: Case report. A 58-year old man with acute anterior ischemic optic neuropathy had repeated NFA/GDx scans of the nerve fiber layer adjacent to the optic nerve head of the involved eye, as well as repeated HFA 30.2 (Humphrey Field Analyzer; Humphrey Systems, San Leandro, California) visual field examinations.

RESULTS: At presentation (day 0), he had a normal superior nerve fiber bundle on the NFA/GDx, with a deep inferior hemifield scotoma. By day 21 and day 36, the superior nerve fiber bundle thinned on the NFA/GDx, whereas the scotoma remained practically unchanged.

CONCLUSION: These findings suggest that after the onset of an anterior ischemic optic neuropathy, acute loss of axonal function results in scotoma, presumably from ischemia. This is followed by a gradual disappearance of nerve fiber tissue, as measured with the NFA/GDx, within several weeks.