Isolated optic atrophy best evaluated by imaging

March 1, 2005

New Orleans—Neuroimaging tests such as MRI appear to have the highest diagnostic value in evaluation of cases of unexplained optic atrophy, while laboratory testing has a low yield, according to Karl C. Golnik, MD.

Imaging should be mandatory in all patients with unexplained optic atrophy and is particularly important in those with positive predictive factors such as a young age, progression, and bilaterality, added Dr. Golnik, associate professor of ophthalmology, University of Cincinnati. He presented results of a retrospective review of cases of isolated optic atrophy at a neuro-ophthalmology free paper session during the American Academy of Ophthalmology meeting.

From 1,110 charts reviewed, Dr. Golnik and his colleagues excluded all but 91 because a cause of the optic atrophy could be identified. Among the 91 cases of suspected isolated optic atrophy, 18 (20%) were found to have compressive lesions such as meningiomas, adenomas, and craniopharyngiomas. Eleven of 18 had bilateral vision loss, and five of 18 had a history of progressive vision loss. In addition, 12 of 18 patients were under age 50, and three of 18 were hemianopic.

As was found in the retrospective review, most causes of optic neuropathy can be defined by history and exam, Dr. Golnik said, but sometimes the optic atrophy is isolated and no obvious etiology can be identified after initial neuro-ophthalmic evaluation.

"There is no evidence-based recommendation that can be made for the evaluation of this sort of isolated optic atrophy," Dr. Golnik said.

A literature review disclosed no randomized clinical trials for optic atrophy evaluation or high-powered, large-sample-size prospective or retrospective studies, although some isolated case series have been reported.

To investigate the usefulness of various patient evaluation approaches, he and his colleagues reviewed charts of patients with a diagnosis of isolated, unexplained optic atrophy, using records compiled over an 8-year period from neuro-ophthalmology units at the University of Cincinnati, the Cincinnati Eye Institute, and the University of Iowa Hospitals.

Inclusion requirements were age 18 years and up, a diagnosis of isolated optic atrophy, no documentation of disc edema at initial presentation, and no other abnormal neurologic findings. In addition, there could be no obvious etiology found after the initial examination.

Patients were excluded if they had known ocular or systemic disorders such as multiple sclerosis, if localized findings suggested that the diagnosis was not an isolated optic atrophy, or if they had a history suggestive of an etiology for the optic atrophy, such as severe trauma.

About half of the patients (51 of 91) whose charts were included in the final review had undergone laboratory studies.

"This was a potpourri such as one might expect to find in a retrospective study," Dr. Golnik said. "Not every patient got every study. There was significant variability."

Because of the retrospective format of the study, the specificity and sensitivity of these tests could not be defined, he added.

He also noted that the study population, a select group of patients referred to tertiary neuro-ophthalmology practices in the Midwest, might not be the same as patients seen in other geographic areas.