Differential Diagnosis of Optic Neuropathy

ABSTRACT

PURPOSE: In order to prospectively investigate the causative mechanisms of visual loss in 42 patients referred to rule out optic neuropathy or diagnosed with optic neuropathy in other hospitals. METHODS: Thorough history taking and ophthalmologic examinations were performed. In some patients, evaluation of extraocular movement, nerve fiber layer photography, contrast sensitivity, visual evoked potential, electroretinogram and visual field were tested. RESULTS: Functional visual loss was most common(18 patients), followed by retinopathy(nine patients). Three patients suffered from amblyopia and glaucoma, respectively, two from keratoconus, pseudopapilledema, miscorrected refractive error, and Leber's congenital amaurosis, respectively, and one from cortical visual impairment. In the differential diagnosis of optic neuropathy, history taking and ophthalmologic examinations including pupillary light reflex, color vision test, nerve fiber layer photography, funduscopy and visual field test were useful. Especially the color vision test was very simple, but useful. CONCLUSION: Clinical entities including functional visual loss and retinopathy should be considered when diagnosing visual loss of unknown etiology.