In Western Australia during the period 1 January 1976 to 31 December 1987 1089 eyes of 1044 patients in hospital were operated upon for primary rhegmatogenous retinal detachment due to causes other than penetrating trauma. Of these eyes 295 (27%) were aphakic or pseudophakic. During this period the annual number of cataract operations in the State increased by a factor of 245%, while aphakic and pseudophakic retinal detachment operations rose by only 55%. The declining risk of retinal detachment following cataract surgery is attributed to improvements in microsurgical techniques. In 1983 and 1984 the incidence of aphakic and pseudophakic retinal detachments dropped significantly (p less than 0.05). At about this time extracapsular cataract surgery became widespread in the State, and this may explain the observed fall in retinal detachment operations. Since 1984 the incidence has risen owing to the rapidly increasing prevalence of pseudophakia in the resident population.