ABSTRACT
OBJECTIVE: Recent research has helped to develop a more detailed understanding of many functional neurologic disorders. The aim of this study was to increase our knowledge of functional visual loss and to compare the findings with those of other functional syndromes. DESIGN: Prospective and retrospective observational cohort study. METHODS: This study took place at neuro-ophthalmology clinics at 3 major hospitals in London, United Kingdom, over a 12-month period. The study population consisted of 157 participants, 100 with functional visual loss, 21 pathologic control subjects with organic visual loss, and 36 healthy nonpathologic control subjects. All participants had their diagnosis confirmed with a full neuro-ophthalmic examination, neuroimaging, and visual electrophysiology. A full assessment of all participants' medical history was obtained from their general practitioner, and all participants completed a series of questionnaires assessing relevant associations. RESULTS: Data were obtained on 157 participants, 100 with functional visual loss, 21 pathologic control subjects with organic visual loss, and 36 healthy nonpathologic control subjects. Participants with functional visual loss were typically female (74%) with a mean age at vision loss of 40.0 ± 16 years. Sixty-four percent of participants had bilateral vision loss; the remainder, unilateral loss. Twenty-six percent of the total cohort had organic visual loss with functional overlay. Fifty percent of participants with functional visual loss had a preexisting psychiatric diagnosis, the most common being a depressive disorder. Sixty-two percent of participants had an ocular history, and 87% had a previously diagnosed medical illness, most commonly neurologic (45%). Thirty-five percent of participants self-reported at least 1 additional functional symptom. CONCLUSIONS: Our population of functional visual loss subjects shares many similarities with the majority of patients with other functional neurologic disorders. They are generally young and female and have a greater than expected rate of psychiatric, medical, and coexisting ocular conditions. We found increased rates of precipitating stressors, clinical depression, and organic eye problems in subjects with functional visual loss.
ABSTRACT
The management of optic neuropathy is fundamental to neuro-ophthalmic practice. Following the invention of the ophthalmoscope, clinicians, for a century or more, relied upon fundus examination in the evaluation of optic neuropathy. However, the advent of optical coherence tomography, based on the principle of backscattering of light and interferometry, has revolutionized the analysis of optic nerve and retinal disorders. Optical coherence tomography has proven of particular value in the measurement, at the micron level, of the peripapillary retinal nerve fibre layer and the ganglion cell layer. These measurements have proven critical in the differential diagnosis and monitoring of optic neuropathy. Specifically, thinning of the peripapillary nerve fibre layer provides evidence of axonal loss affecting any sector of the optic nerve. Thinning of the macular ganglion cell layer, on the other hand, shows a more precise correlation with visual deficits due to retrograde degeneration following optic nerve damage, although limited to central retina. In daily practise, optical coherence tomography is of great value in assessing the diagnosis, prognosis and response to treatment in optic neuropathy. Particular advances have been made, for example, in the assessment of optic neuritis, papilloedema and chiasmal compression which have translated to everyday practice. As with any other imaging technology the clinician must have a clear understanding of acquisition artefacts. A further issue is the relatively limited normative database in sub-populations such as the young and individuals with a refractive error > + 5 or < -5 dioptres.
