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L. Abetz, K. Venkataraman, P. Mertzanis, R. Chalmers, C. Begley; The Development, Reliability and Validity of a Questionnaire to Assess the Impact of Dry Eyes on Everyday Life (IDEEL) . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2477.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Little information is available on the impact of dry eyes on patients’ lives. The purpose of this study was to develop and validate a comprehensive patient reported outcomes instrument that focuses on the impact of dry eyes on every day life (IDEEL). Methods: Information gathered from focus groups with 45 American and Canadian dry eye sufferers was used to develop the IDEEL. Subsequently, the IDEEL was completed twice over a two-week period by 210 people: 48 controls, 130 with mild to severe dry eye and 32 with Sjogren’s Syndrome (SS). The SF-36 and EQ-5D, generic measures of health status, were administered at baseline. Results: Interview results suggested that dry eyes impact a range of daily activities; SS patients experienced even greater burden. Based on the interviews, the 113-item IDEEL was developed and included questions on daily activity limitations, emotional well-being, work limitations, symptom bother and treatment satisfaction. Psychometric validation suggested the removal of 56 items, yielding 3 modules (quality of life (27 items), symptom-bother (20 items), and treatment satisfaction (10 items)) and 6 scale scores (emotional well-being, activity limitations, work limitations, symptom bother, treatment satisfaction, treatment-related bother). All standards for item convergent validity (item-scale correlations greater than 0.4) and item discriminant validity (>=90% of items have correlations higher with own scale than with other scale) were met. Internal consistency (Cronbach’s alpha) and test-retest reliability (intra-class correlation (ICC)) coefficients for all summary scores met or exceeded the standard of 0.70 (Cronbach’s alpha range: 0.70-0.97; ICC range 0.82-0.94). With the exception of treatment satisfaction, IDEEL scales were able to significantly discriminate between diagnoses (no dry eye, dry eye, Sjogren’s Syndrome), clinician reported severity and patient reported severity, indicating discriminative validity. The IDEEL was also better able to discriminate between severity indices than the generic measures (SF-36 and EQ-5D). Conclusions: These results indicate that the IDEEL is reliable and valid and appropriate for use as a clinical endpoint in trials of dry eye treatments. The IDEEL’s ability to distinguish between a range of severity levels provides preliminary evidence that the IDEEL will be responsive to dry eye changes over time.
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