True or pseudo optic disc edema: clinically-based approach to the differential diagnosis.

Purpose: To present a clinically based approach to the differentiation of optic disc edema (DE) cases, commonly seen in neuro-ophthalmology.

Methods: Consecutive patients who were considered to have unilateral or bilateral DE during examinations in the outpatient clinic and were referred to the neuro-ophthalmology department were included in this prospective study. The examination findings and differential diagnosis based on clinical signs and symptoms, and neuro-ophthalmological approach were evaluated in cases of DE.

Results: Of the 119 cases with DE, 69 (58%) were women and 50 (42%) were men, where 89 (75%) had true optic DE (ODE) and 30 (25%) had pseudo optic DE  (PODE). Non-arteritic anterior ischemic optic neuropathy (n = 40), increased intracranial pressure (n = 32), and anterior optic neuritis (n = 17) were determined as the causes of true ODE, whereas small and crowded optic disc (n = 12), tilted optic disc (n = 8), myelinated nerve fibers (n = 5) and optic disc drusen (n = 5) as the causes of PODE. Patients with optic neuritis were the youngest (28.41 years) group of ODE cases while those with non-arteritic anterior ischemic optic neuropathy were the oldest (59.98 years). The first symptoms were sudden and painless loss of vision and/or visual field in cases with non-arteritic anterior ischemic optic neuropathy, pain increasing with eye movements and loss of vision and/or visual field in cases with optic neuritis, headache, and from time to time blurred vision in cases with increased intracranial pressure. Patients having vision loss due to amblyopia constituted (30%) of PODE cases while 70% were determined incidentally and they had the best visual acuity. The accuracy of the preliminary diagnosis based on neuro-ophthalmologic examination findings was 79% in all cases.

Conclusion: Detailed history taking and neuro-ophthalmological examination are essential in the differential diagnosis of ODE and PODE.