Abstract
BACKGROUND: Blepharitis is an ocular surface disease and chronic ophthalmic condition. This paper reports on the development of psychometric evaluation of a patient-reported measure of blepharitis symptoms. METHODS: Self-reports of 13 blepharitis symptoms collected in a Phase 3 multi-site, randomized, double-masked, 4-arm parallel group, clinical trial of 907 individuals with blepharitis (mean age = 62, range: 19-93; 57% female) were analyzed. Symptoms asked about were: eyes that itch; eyes that burn; eyelids feel heavy or puffy; feel like something is in your eye; dry eyes; gritty eyes; irritated eyes; eyes that tear or water; crusty eyes; flaking from your eyelids; eyelids that are stuck together; red eyes or eyelids; and debris like pieces of skin or dandruff in your eyes. RESULTS: Categorical factor analyses provided support for two multi-item symptom scales: Irritation (9 items, alpha = 0.88) and Debris (4 items, alpha = 0.85). Spearman-rank order correlations of the Irritation and Debris scales with the Ocular Surface Disease total score were 0.63 and 0.41, respectively (p's < 0.001). Rank-order correlations between ratings of clinicians and self-reports of puffy eyes (r = 0.07, p < .05), red eyes (r = 0.12, p < .001), debris (r = 0.03, p > 0.05), and irritation (r = 0.47, p < .001). CONCLUSIONS: This study provides support for the psychometric properties and construct validity of the Irritation and Debris scales for assessing symptoms of blepharitis. The associations between the self-reports and clinician ratings of 4 symptoms indicate substantial unique information in the new self-reported symptom items. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov under the registry number NCT01408082 .