OBJECTIVES: Age related macular degeneration (AMD) is the leading cause of blindness in the United Kingdom and the rest of the western world, occurring in 15% to 30% of those over 75 years of age. About 15% of these patients develop a more aggressive wet form of the disease that causes severe loss of vision METHODS: Costs considered are those for treatment and social care for people with low vision. The benefit estimates come from a 2-year clinical trial of 609 patients that compared PDT with verteporfin to placebo. A Markov model was used to extrapolate the results of the trial to a 5-year time horizon. Transition rates in the model were based on a time-to-event analysis using a Weibull parametric hazard, with the assumption that the treated eye is the better seeing eye. Two outcomes were measured, vision years gained and quality adjusted life years (QALYs) gained. RESULTS: The cost per vision year gained estimates range from £13,000 to £15,000 over 2years, while those modelled to 5years range from £5,000 to £9,000. The cost per QALY gained within the trial time frame range from £58,000 to £66,000, and is estimated to range from £22,000 to £43,000 at 5 years. Earlier intervention has greater expected cost effectiveness in the long term, in spite of more treatments being given overall. For example, with a 5-year follow-up, starting a treatment cohort at 20/40 yields an expected cost per QALY of £22,000-£30,000, but starting a cohort at 20/100 yields an expected cost per QALY of £34,000-£43,000. The main driver in the costs for the treatment group is the cost of therapy, and these costs are estimated to occur mainly in the first 2 years. CONCLUSION: Early intervention may yield acceptable cost-effectiveness levels. Consideration should be given to early detection and treatment of people with AMD.