Etiological and clinical characteristics of infectious optic neuritis

Fifty-one patients with infectious optic neuritis (ION) with no associated choroidal or retinal involvement were studied in relation to the etiologic agents, and to the epidemiological and clinical features to look up features which could be used to distinct them from the demyelinating optic neuritis (DON) which have a well-known tendency to convert to multiple sclerosis. Bilateral involvement was found in 23 patients (45.1%), simultaneously in 18 cases. Sex distribution was 2M: IE The ages ranged from 1 to 82 years (median 34.8); 1/3 of the patients were younger than 20 and 1/3 were 50 years of age or older. Syphilis was found in 19 patients being the single most common etiology, whereas viral infetions were found in 41.2% of the cases. Visual acuity was severely damaged in most patients and was worse than 20/200 in 57.3% of the involved eyes. Color vision was affected in 91.8%. Visual field defects were round in 92.2%, with predominance of the central defects (40.7%). The optic disc was abnormal in 90.5% of the eyes. This study clearly demonstrates that ION and DON have distinct epidemiological and clinical features. The awareness of these differences may help clinicians to follow different paths for the correct diagnosis and appropriate treatment and prognostic orientation of their patients.