Medically unexplained visual loss in adult patients.

PURPOSE: To evaluate the characteristics of patients with nonorganic or medically unexplained visual loss (MUVL) presenting to a neuro-ophthalmology clinic.

METHODS: A retrospective review of the case notes of patients identified from our diagnostic register. All patients had been followed up for at least 18 months and investigations (including, in all cases, neuroimaging) had failed to reveal any underlying pathology. To be included, patients had to have at least one inconsistent feature on visual function testing.

RESULTS: : We identified 58 patients with MUVL. A total of 79% of patients were female and 21% were male. In total, 36% of patients had been seen in other medical specialties with unexplained symptoms. In all, 60% of patients complained of glare or pain. Of the patients with bilateral visual loss, the acuities were frequently the same in each eye and the most common pattern of visual field loss was concentric contraction. Those with unilateral visual loss had a more variable pattern of visual failure. In total, 22% of patients showed some visual recovery though this was usually incomplete. In one patient, organic pathology accounting for the visual symptoms became apparent after the end of the 18 month follow-up period.

CONCLUSIONS: Medically unexplained symptoms, in general, form an important part of the workload in most medical specialties. Unexplained symptoms in ophthalmology have not been well studied. Terminology should be brought into line with that used in other medical specialties. Further work may help in the identification of positive diagnostic features of MUVL which should not be simply a 'diagnosis of exclusion'.