A rating scale is a proper method to evaluate changes in quality of life due to dry eye symptoms

Purpose: To determine which utility value assessment method is more suitable to evaluate changes in the quality of life due to dry eye symptoms.

Methods: Dry eye outpatients with a presenting visual acuity of 20/25 or better in the worse-seeing eye were recruited. Presenting distance visual acuity, tear film break-up time, Schirmer I test and fluorescein were assessed. The severity of dry eye symptoms was assessed using the Ocular Surface Disease Index (OSDI), and utility values were measured using the time trade-off (TTO), standard gamble (SG1 and SG2) and rating scale (RS) methods. Different utility values were compared with each other. The most appropriate utility value method to evaluate quality-of-life changes solely due to dry eye symptoms is determined by calculating the correlation between the OSDI score and different utility values.

Results: A total of 104 patients were enrolled. The three sections of OSDI in the order of high to low scores were as follows: "environmental trigger," "eye discomfort" and "visual function." The utility scores measured with TTO, SG1, SG2 and RS were 0.95 ± 0.11, 0.96 ± 0.10, 0.99 ± 0.07 and 0.89 ± 0.10, respectively. The utility scores evaluated by the TTO, SG1, SG2 and RS methods were significantly different from each other (p < 0.05). Only the utility scores measured with RS were significantly correlated with the composite OSDI score, "environmental trigger" and "eye discomfort" section scores (p < 0.05).

Conclusions: RS is more sensitive than TTO and SG for the evaluation of altered quality of life due to dry eye symptoms.