The cupped disc. Who needs neuroimaging?

Abstract

Objective: To determine the incidence of positive neuroradiologic studies in consecutive patients with glaucoma associated with normal intraocular pressure and to compare the psychophysical and clinical characteristics of these eyes with eyes with disc cupping associated with intracranial masses.

Design: Retrospective case-controlled study.

Participants: Fifty-two eyes of 29 patients with glaucoma associated with normal intraocular pressure and 44 eyes of 28 control patients with compressive lesions were reviewed.

Intervention: The medical records of consecutive glaucoma patients with normal intraocular pressure who underwent brain magnetic resonance imaging or computed tomography scanning as part of a diagnostic evaluation between January 1, 1985, and July 1, 1995, were reviewed. A masked reading of optic nerve photographs and visual fields was performed by one observer. A similar analysis was performed on a control group of consecutive patients with nonglaucomatous optic nerve cupping with known intracranial mass lesions.

Main outcome measures: The neuroradiologic findings, clinical characteristics, optic nerve head appearance, and patterns of visual field loss were compared between groups.

Results: None of the patients diagnosed with glaucoma had neuroradiologic evidence of a mass lesion involving the anterior visual pathway. Compared to control subjects, patients with glaucoma were older (P = 0.0001), had better visual acuity (P = 0.002), greater vertical loss of neuroretinal rim tissue (P = 0.0001), more frequent optic disc hemorrhages (P = 0.01), less neuroretinal rim pallor (P = 0.0001), and more nerve fiber bundle visual field defects aligned at the horizontal midline (P = 0.0001). Visual acuity less than 20/40, vertically aligned visual field defects, optic nerve pallor in excess of cupping, and age younger than 50 years were 77%, 81%, 90%, and 93% specific for nonglaucomatous cupping associated with compressive lesions, respectively.

Conclusions: Anterior visual pathway compression is an uncommon finding in the neuroradiologic evaluation of patients with a presumptive diagnosis of normal-tension glaucoma. Younger age, lower levels of visual acuity, vertically aligned visual field defects, and neuroretinal rim pallor may increase the likelihood of identifying an intracranial mass lesion.