This study was performed to document the prevalence of pre-existing medical disease amongst 105 patients awaiting ophthalmic surgery, and to assess the usefulness of investigations performed in accordance with the guidelines of the Joint Working Party on Anaesthesia in Ophthalmic Surgery. Patients attending the preoperative assessment clinic prior to ophthalmic surgery all had a full medical history taken and a clinical examination performed, Investigations were then ordered in accordance with the guidelines of the Joint Working Party on Anaesthesia in Ophthalmic Surgery, Pre-existing disease was present in 74 patients and abnormal results were obtained from 77 of the 318 investigations, Only 132 of the investigations were felt to be clinically indicated, and of the 77 abnormal results only 11 were unexpected, Despite the high prevalence of medical disease, patients awaiting ophthalmic surgery should be investigated only when clinically indicated and not on the basis of age or sex alone.