Psychogenic amblyopia and Stargardt's disease the differential diagnosis

Abstract

Psychogenic amblyopia and Stargardt's disease are visual loss in children; however, their prognoses and management differ greatly. Stargardt's disease is a progressive bilateral macular dystrophy, with autosomal recessive inheritance. In time, visual acuity may decrease to 6/60. Stargardt's disease is characterised by retinal pigment epithelial defects on fluorescein angiography, and prolonged photostress recovery time. The ophthalmoscopic appearance is of macular atrophy and yellow flecks surrounding the macula (fundus flavimaculatus), although initially die macular appearance may be unremarkable. Psychogenic amblyopia is a juvenile functional bilateral amblyopia. Alternative labels include Streff syndrome, functional visual loss, visual conversion reaction, and hysterical amblyopia. Patients with psychogenic amblyopia often have multiple symptoms, as well as a reduced academic achievement. It is linked to visual or emotional stress and the prognosis is usually good. Visual acuity measures are variable, kinetic visual fields may spiral, and an accommodative/vergence disorder is often present. Two patients are presented to illustrate the differential diagnosis and management of the two conditions.