Validity and reliability of the Persian translation of the McMonnies dry eye questionnaire.

Abstract

Clinical relevance: Forty-nine dry eye questionnaires are available which are different in terms of purpose, length, target population, mode of administration, and content. Psychometric characteristics of a questionnaire in a specific population can determine how effective it will work. and reveal the importance of the studies in this regard.

Background: The McMonnies questionnaire (MQ) is one of the effective tools widely used for dry eye screening. The purpose of this study was to translate the McMonnies dry eye questionnaire into Persian language and assess its validity and reliability.

Methods: Translation and cultural adjustment of the English language McMonnies dry eye questionnaire into Persian was performed. Forty-two patients with dry eye and 42 healthy subjects were involved and validity and reliability aspects of the questionnaire were evaluated. All the participants were asked to complete the Persian translation of the McMonnies dry eye questionnaire, at baseline and 2 weeks later. Statistical analyses of the survey items were conducted using SPSS version 23.

Results: Based on standardised items, the Cronbach ⍺ was acceptable (0.714). The items correlated well with an average inter-item correlation of 0.173 (range, 0.118 to 0.246). The test-retest reliability was high and significant (r = 0.988, p < 0.001). All the items showed factor loadings greater than 0.50. For the recommended cut-off point of 14.5, the sensitivity and specificity were 42.5% and 100% respectively. These values changed to 85.7% and 81% with a new cut-off point of 9.5.

Conclusion: The Persian McMonnies questionnaire demonstrated acceptable internal consistency, good validity, and acceptable accuracy as a screening tool for dry eye in the Persian population. To increase the sensitivity of the instrument, a new cut-off point should be considered.