Objective: Patient satisfaction with glaucoma therapy is one of the aspects that affects adequate adherence to treatment; therefore, it would be interesting to measure the satisfaction properly. We present the development process and psychometric properties of a new instrument for measuring patient satisfaction with glaucoma treatment.
Material and methods: After collection and discussion of contents, a 38-item questionnaire was proposed and arranged into seven theoretical domains. The questionnaire was applied to a sample of 194 patients and its length was reduced using an exploratory factor analysis. Psychometric properties were assessed under classic theory.
Results: The final questionnaire is formed by 22 items grouped into seven dimensions: expectations and beliefs about treatment, ease of use, efficacy, undesired effects, impact on health-related quality of life, medical care, and general satisfaction with treatment. Some dimensions correlated slightly. The reliability of the dimensions ranged from 0.77 to 0.93. Confirmatory factor analysis revealed an additional support of the proposed structure (chi(2) (188) = 217, P = 0.073). Glausat scores were proven to correlate with patients' self rating on medication tolerability, and with clinicians' assessment of tolerability, effectiveness and compliance.
Conclusions: The Glausat questionnaire has proven to be reliable and structurally valid. This instrument may be used to assess patients' satisfaction with glaucoma treatment.