Psychogenic medicine Non-organic visual loss

Visual complaints without a physical basis are not uncommon presentations to the general physician , the neurologist, or the ophthalmologist. These alleged visual disturbances may be psy-chogenic or feigned. The diagnosis is made when all possible contributory pathology of the visual system is excluded, and reassurance remains the cornerstone of management. Visual complaints without evidence of contributory ocular or non-ocular pathology are not infrequent presentations to the general Accident and Emergency department, and are said to account for approximately 1% of visual problems seen by the ophthalmologist. 1 The wide spectrum of terminology used to describe visual disturbance without a physical basis, which includes 'functional', 'hysterical' (amblyopia), 'conversion disorder', 'neurotic', 2 'supratentorial', 2 and 'psychosomatic', has resulted in considerable confusion. In this review we use the term non-organic visual loss (NOVL) to describe any visual disturbance where there is no detectable dysfunction of structures between cornea and occipital cortex. NOVL may be psychogenic, or the result of malingering. Psychogenic visual complaints result from a disturbance of higher cortical structures occupied with visual awareness, and patients with this form of NOVL do experience but do not control their visual symptoms. The malingerer, on the other hand, deliberately feigns visual loss for secondary gain. The term 'malingering' is in many ways a moral accusation rather than a clinical diagnosis, and consequently should only be used with extreme caution. In the vast majority of cases the distinction between psychogenic visual complaints and malingering is not made, and the term non-organic visual loss is used. In this article we review the literature concerning NOVL, and provide up-to-date guidelines on the most appropriate investigative and therapeutic approach to patients with unexplained visual symptoms. Loss of acuity NOVL is more common among younger age-groups and females. 1 3–8 The most frequently reported non-organic visual complaints include a reduction of visual acuity with or without loss of field (36–80%). 3 9 Isolated visual field defects in the presence of normal acuity are less frequent at 14–20%, 3 9 and visual symptoms are binocular in the majority of cases (50–80%). There are no features of a clinical history that are pathognomonic of non-organic visual loss, but the onset of alleged visual loss is usually not typical of known pathology. It has been noted, however, that patients with psychogenic complaints are highly suggestible, whereas malingerers " try too hard " to convince the physician of their symptoms. 13 A …