Eighty-three patients with retinal pigment epitheliopathy have been identified from the photographic and fluorescein records of the Tennent Institute of Ophthalmology in Glasgow. Many have been brought back for follow-up assessment. Twenty-seven patients had placoid lesions, 22 geographic lesions and 15 a condition which we propose to rename the 'not ocular histoplasmosis' (NOH) syndrome. Patients with placoid lesions could be divided into typical acute multifocal placoid pigment epitheliopathy (AMPPE), where the long-term visual prognosis was poor because of recurrent disease leading to extensive areas of atrophy, and acute diffuse placoid pigment epitheliopathy which seemed to be self-limiting. No consistent evidence of viral or immunological abnormality was found in either group of patients. Geographic lesions appeared to result either from a coalescence of focal lesions or from a slow (serpiginous) spread from a single focus. Four patients with helicoid atrophy lost central vision from disciform lesions. Seven patients had pigment epithelial disorder associated with sarcoidosis. The pigment epithelial disease was unresponsive to systemic corticosteroid therapy and tended to be complicated by disciform lesions. Disciform lesions may occur in any type of pigment epitheliopathy, as may serous retinal detachment or pigment epithelial detachment. A technique for the biopsy of choroid and retinal pigment epithelium is described. This may lead to a better understanding of these disorders.