The specific aim of this proposal is develop a method that will allow quality of life and economic investigators to distinguish between health-related quality of life (as measured by utility) that is due to visual impairment, and that which is due to other health-related and/or demographic factors. The outcome of this project will allow economic investigators and clinical trialists to more precisely evaluate benefits of ophthalmic interventions, thus insuring an accurate estimate of the balance between cost and benefit of the treatment and prevention of eye disease. The proposed analysis will use data collected in the NEI funded project, """"""""Assessing Patient Preferences for Visual Acuity Loss"""""""" (R01EY011871-01). This was a cross-sectional study in which investigators interviewed 443 participants in the St. Louis area between June 1998 and October 1999, each with one vision related disease: diabetic retinopathy (n=59), glaucoma (n=99), macular degeneration (n=44), age-related cataract (n=132), and correctable refractive error (n=109). All data were collected and disease impairment characterized according to the NEI-VFQ protocol and included utilities elicited using the standard gamble. We propose to use this data to identify items or scales from the NEI-VFQ or SF-36 that measure utility. A conceptual model describing health-related quality of life will be constructed by experts in eye disease and occupational therapy. The model will distinguish between quality of life that is the result of vision-related factors and other aspects of health. The model will then be estimated using structural equation modeling methods. Validation of the model will be conducted in a subset of the 443 participants. Validation of the models estimates of utility will be conducted by comparing the model estimates to those reported by the study participants. Vision specific utility will be validated using a construct validity method. The social consequence of continued growth is health care spending has been well reported. While in the past the visual sciences have been somewhat immune to concerns over growth in expenditures, the aging of Americans with the associated increase in visual disease adds urgency to the need to make informed decisions concerning the allocation of scarce resources. A cost-utility analysis is a widely accepted method of assessing the cost-effectiveness of treatment or prevention of disease. However, the process of directly eliciting utility is time consuming and cognitively challenging. Questionnaires that indirectly assess utility have been shown to be insensitive to clinically significant changes in ocular disease. If we are to accurately assess the cost-effectiveness of vision related interventions, we must develop instruments that accurately measure vision-specific utility while minimizing respondent burden. ? ? ? ? ? ? ?
