Functional vision disorders in adults: a paradigm and nomenclature shift for ophthalmology

Abstract

Vision loss with clinical findings that are incompatible with the symptoms and recognized neurological or ophthalmic conditions is a common presentation of patients to neurologists, ophthalmologists, and neuro-ophthalmologists. The accepted terminology to describe such patients has evolved over time, including functional visual disorder (FVD), non-organic vision loss, non-physiologic vision loss, functional vision loss, psychogenic, psychosomatic, and medically unexplained visual loss. Likewise, attitudes and recommended management options have changed over the years in the fields of psychiatry and neurology. FVD is a diagnosis of inclusion, and it is critical that the diagnosis be made and delivered efficiently and effectively to reduce patient and physician duress. We review the current Diagnostic and Statistical Manual (DSM V) terminology and the prior literature on FVD and describe how the approaches to diagnosis and management have changed. We provide recommendations on the appropriate techniques and diagnostic approach for patients with FVD. We also propose a protocol for consistent and standardized discussion with the patient of the diagnosis of FVD. We believe that the adoption of FVD as both a paradigm and nomenclature shift in ophthalmology will improve patient care.

Keywords: Functional vision disorder; SPIKES; functional neurologic disorder; functional visual loss; medically unexplained vision loss; non-organic vision loss; psychogenic vision loss.

Figure 1:

Changes in descriptions of functional vision loss per decade in the literature

Figure 2:

Normally, the visual field at 2 meters is doubled compared to the visual field at 1 meter. However, patients with functional vision loss may report the same size of visual field at increased distance.

Figure 3:

Representative Goldmann visual field patterns suggestive of functional visual disorder. A. Symmetric constriction (tunnel vision) B. Spiraling of isopters C. Crossing of isopters

Figure 4:

Representative Goldmann visual fields with binocular testing for a patient with FVD claiming monocular vision loss. A. Left eye (OS) shows a temporal hemianopia B. Right eye (OD) shows a normal visual field C. Binocular (OU) visual field demonstrates a persistent temporal defect, indicative of a functional visual disorder. Physiologic results on binocular testing would demonstrate an enlargement of the visual field as the right eye compensates.