To validate the Persian translation of the Glaucoma Quality of Life-15 (GQL-15) questionnaire, evaluate its psychometric properties, and identify new composite items and item numbers.

In this cross-sectional study 190 patients with glaucoma were enrolled from a glaucoma clinic in Shiraz, Iran. Data on sociodemograghic characteristics were collected . Habitual-corrected visual acuity, intraocular pressure, slit-lamp biomicroscopy, fundus exam and mean visual field defects were recorded. The Persian version of the GQL-15 was administered in face-to-face interviews, and psychometric properties, i.e. test-retest reliability, internal consistency, content validity and construct validity were evaluated with factor analysis. Based on the Disc Damage Likelihood Scale, patients were stratified according to mild, moderate, and severe disc damage, and discriminant validity was evalated with multinomial logistic regression by adjusting for some clinical and demographic variables.

Of 190 eligible glaucoma patients, reliable clinical data were available for 140 participants. Mean age (SD) of the patients was 58.7 (13.3) years. Cronbach’s α coefficient ranged from 0.74 to 0.91, and the overall correlation coefficient for all analyses was 0.53. The content validity ratio was 0.91 based on evaluations by five experts in the field. Exploratory factor analysis based on eigenvalues higher than one identified two factors after varimax rotation for the GQL-15 which explained 66.5% of the total variance. Discriminant validity analysis disclosed statistically significant differences in mean quality of life scores between levels of disease severity.

The Persian version of the GQL-15 is a reliable and valid questionnaire for use in ophthalmology clinics as a complementary tool for evidence-based decision-making, and is applicable in further clinical research on glaucoma in Persian-speaking populations.