The impact of persistent visually disabling vitreous floaters on health status utility values

To assess the time trade-off (TTO) utility values in patients with persistent visually disabling vitreous floaters (DVF) and to determine the reliability and validity of TTO methods in DVF patients.

Prospective cross-sectional questionnaire survey: Eligible patients with persistent DVF referred to the Shanghai First People's Hospital outpatient service between January 2006 and February 2010, and randomly selected normal vision general population residents, were enrolled. All participants underwent TTO utility value evaluation. After 4-5 weeks, the patients were asked to undergo second TTO utility value evaluation during the follow-up interview.

The mean initial utility values of the 107 persistent DVF patients were 0.904 ± 0.054. Regression analyses revealed that length of education, visual acuity in the poorer-vision eye and employment status were associated with utility values (all P < 0.01). All patients took part in the follow-up interview; the intra-class correlation coefficient for TTO utility values at the initial and follow-up interviews was 0.855. In the 91 general population residents, the mean utility value was 0.923 ± 0.032, which was statistically higher than that of active study patients (t = 3.01, P < 0.01).

Persistent DVF can substantially diminish the patients' perception of their life, and can be measured by TTO utility values with high reliability and construct validity.