Cataract surgery and intraocular lens implantation has taken on many significant advances since its earliest inception. As the prevalence of the aged population increases the number of cataract operations also increases year on year. In the UK last year over 300,000 cataract operations were performed with 2 million in Europe and 1.5 million in the USA. Globally 8.7 million cataract operations are performed per annum. Technical advances are occurring ever more rapidly in this procedure enabling improved preoperative assessment and surgical management. This has produced a sophisticated procedure which is eminently reproducible. In concordance with such improvements both patient and doctors expectations for visual results have also risen. The expectation is now that the operation will achieve more than mere removal of a pathological opacity interfering with the visual process. The possibility and expectation is that the procedure will be tailored specifically to the patient in such a way that the best possible visual result will be achieved through customization of the surgical process to optimize the individual's optical system. Optimization of any particular process may be complex, and cataract surgery is no exception. Careful consideration of many interrelated factors including a patient's functional visual requirements, along with specific anatomical and unique optical factors will be required if an optimum result is to be achieved. The decision making process involved in determining how an individual eye should be surgically customised, can therefore be complicated. These are the situations where decision support systems become most beneficial, to ensure consistent successful results, particularly if technical measurements are being performed by individuals with varying degrees of experience.