Purpose To quantify decreases in health-related quality of life (HRQoL) for given deterioration in clinical measures of vision; to describe the shape of these relationships; and to test whether the gradients of these relationships change with duration of visual loss. Design A prospective, longitudinal study of patients treated with verteporfin photodynamic therapy in the United Kingdom National Health Service. Participants Patients with neovascular age-related macular degeneration (AMD) treated in 18 ophthalmology departments in the United Kingdom with expertise in management of neovascular AMD. Methods Responses to HRQoL questionnaires (Short Form 36 [SF-36] and National Eye Institute Visual Functioning Questionnaire [NEIVFQ]) and clinical measures of vision were recorded at baseline and at follow-up visits. Mixed regression models were used to characterize the relationships of interest. Main Outcome Measures Measures of vision were best-corrected visual acuity (BCVA) and contrast sensitivity (CS). The SF-36 physical and mental component scores (PCS and MCS), SF-6D utility, and distance, near, and composite NEIVFQ scores were derived to characterize HRQoL. Results The SF-6D, PCS, and MCS were linearly associated with BCVA; predicted decreases for a 5-letter drop in BCVA in the better-seeing eye were 0.0058, 0.245, and 0.546, respectively (all P<0.0001). Gradients were not influenced by duration of follow-up. Models predicting distance, near, and composite NEIVFQ scores from BCVA were quadratic; predicted decreases for a 5-letter drop in BCVA in the better-seeing eye were 5.08, 5.48, and 3.90, respectively (all P<0.0001). The BCVA predicted HRQoL scores more strongly than CS. Conclusions Clinically significant deterioration in clinical measures of vision is associated with small decreases in generic and vision-specific HRQoL. Our findings are important for further research modeling the cost effectiveness of current and future interventions for neovascular AMD. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.