Purpose:
Preference–based assessment of quality of life yields "utilities" that assist in decision–making concerning treatment and prevention of disease. Applications include cost–effectiveness research and the development of patient decision support tools. There are few studies of utility loss for visual impairment (VI).
Methods:
We interviewed 443 patients: diabetic retinopathy (DR) =59, glaucoma=99, macular degeneration (AMD)=44, cataract=132, correctable refractive error (RE)=109. Degree of VI was characterized for the disease. Utilities were estimated using the standard gamble, an approach that measures the risk of an adverse outcome accepted to achieve a desired result. We report three scenarios: 1) assuming unilateral blindness, what risk of death would be accepted to gain ideal vision; 2) assuming bilateral blindness, what risk of death would be accepted to gain ideal vision; 3) what risk of death would be accepted to gain perfect health (including ideal vision). The utility score is 1–the risk of death accepted. Age and comorbidity adjusted estimates were made using ANOVA.
Results:
The utility for unilateral blindness and bilateral blindness was consistent across cause of VI. Lower utility scores were found to be associated with increased severity of DR, glaucoma and AMD, with modest loss in early stages. There was little evidence of larger utility loss with increased severity of cataract or RE.
Conclusions:
Our estimate of utility loss associated with bilateral blindness reflects that reported elsewhere. We believe this is the first report of utility loss associated with unilateral blindness, however the use of "ideal vision" for the upper anchor may limit applicability of both estimates. Preference based measures were responsive to severity of DM, glaucoma and AMD but not cataract or RE. Improved assessment of utilities associated with DM, glaucoma and AMD will enhance the ability of clinicians and policy makers to advise patients of treatment options and in identifying cost–effective strategies for treatment and prevention of eye disease.
Keywords: quality of life • clinical (human) or epidemiologic studies: natural history