• blindness
• age related macular generation
• elderly people

Age related macular degeneration (AMD), particularly the wet variant, is an important cause of blindness and a serious public health challenge in older people. A recent health technology appraisal for the National Institute for Clinical Excellence (NICE) of a new treatment, photodynamic therapy for AMD, included the requirement to model the cost utility of treatment. (Cost utility analysis is a form of economic evaluation which compares the cost of two alternative interventions and their health outcomes expressed as a single index that combines length of life and quality of life. Cost utility is usually given as a cost per quality adjusted life year.)

In this it was necessary to include the costs averted by the treatment preventing people becoming blind.¹ These are costs averted that the government would have spent supporting the blind person, such as visual rehabilitation, social services, or local authority care rather than the cost of blindness to the individual affected.² Generating a cost of blindness is a generic feature of cost utility models of a variety of other treatments in similar eye conditions such as diabetic retinopathy.^3,4 In these, the blindness cost estimate is often based on a 1990 US federal budgetary cost.⁵ This estimate for a blind person over retirement age was very low (US$32). Obviously it did not take into account other public expenditure so would have been inappropriate to a UK based health technology assessment more than 10 years later. Another approach taken when conducting cost utility analyses is to only include the cost of treatment and ignore the costs averted. This can be done if a “for profit” third party insurer perspective is taken, but again …