Development and validation of a short global dry eye symptom index

We have developed and evaluated the repeatability of a short questionnaire based on a visual analog scale (VAS) to quantify the frequency and severity of symptoms of dry eye syndrome (DES). The "Symptom Assessment IN Dry Eye" (SANDE) questionnaire utilizes a 100 mm horizontal VAS technique to quantify patient symptoms of ocular dryness and/or irritation. Fifty-two subjects with DES were prospectively enrolled and followed-up at 2 and 4 months with repeated administrations of the SANDE questionnaire and clinical ocular surface evaluation. Subjects demonstrated a wide range of symptom scores indicative of the variability of the disease. Analyses comparing the repeatability of SANDE scores from baseline to the 2-month follow-up indicated a significant downward regression of scores toward the mean. In contrast, repeatability measures were consistently good for questionnaires administered within a few days of one another (ICC ranging from 0.53 to 0.76). Bland-Altman analysis demonstrated that 50% of repeated SANDE symptom scores were within 10 mm of each other, 80% were within 20 mm, and 95% were within less than 30 mm. These data describe good repeatability for the SANDE symptom score when repeated assessments are made within a few days. The results are encouraging and suggest that further refinement and testing of the SANDE questionnaire in larger populations may result in a reliable questionnaire to detect change in irritative symptoms over time.