To conserve limited resources, healthcare purchasers are questioning whether they should ration second eye cataract surgery after successful unilateral extraction. The effect this would have on overall cataract workload is unknown. The clinical indications for performing second eye cataract extraction were recorded from the medical notes of a random group of patients undergoing second eye surgery over a 1 year period. Twenty-six per cent of all cataract operations were on second eyes and, of these, 21.5% of operations were on patients with coexistent ocular pathology, requiring clear optical media for disease monitoring, and 18.4% were on patients who had failed to achieve a satisfactory result after unilateral cataract surgery (visual acuity 6/18 or worse). Another 43.6% had severe binocular visual disability due to their remaining cataract. Only 4.4% of all cataract operations performed during the study period were on second eyes of patients with no other ocular pathology who had had successful unilateral surgery and had only mild symptoms from their remaining cataract (visual acuity 6/12 or better in second eye). Therefore, the overall savings made by rationing second eye cataract surgery to those patients who have only mild visual disability would be slight. If the proportion of cataract operations performed as daycases under local anaesthetic were increased, sufficient resources would be released to enable all patients to achieve maximum binocular visual rehabilitation.