Economic evaluation of health technology using cost-utility analysis (CUA) normally applies an extra-welfarist framework in which health, the unit of effectiveness, is maximised. Typically, health status is measured by health-related quality of life (HRQoL) questionnaires to define health states. Preferences for health states are valued on a utility scale and combined with the time spent in the state to calculate quality-adjusted life years (QALYs). This thesis develops methods for measuring and valuing health using the case of age-related macular degeneration (AMD), where there are limitations with current methods for calculating QALYs.