Abstract
Purpose: :
Although symptoms of ocular irritation may not correlate well with signs, it is widely accepted that a validated symptom questionnaire is vital to dry eye diagnosis and treatment. We modified an efficient, previously validated questionnaire to make it quantitative and characterized it in dry eye subjects that varied in severity and sub–type.
Methods: :
The six–question instrument developed by Schein and co–workers (Ophthalmol.,104:1395, 1997) was modified by adding a category of "never" for frequency and giving each of the five possible frequency responses a numerical value of 0–4. Thus the instrument provides a nearly–continuous measurement scale. One–hundred nine clinic–based subjects were screened for dry eye using the modified instrument and a battery of noninvasive (e.g., lipid interferometry and tear meniscus height) and invasive (e.g., TBUT, fluorescein and rose bengal staining, Schirmer I) tests. Specific diagnostic criteria to determine whether "dry" or "normal" were: TBUT < 7 secs, ocular surface damage using either fluorescein staining > 4 (0–4 score/zone, NEI five zone system, 20 maximum,) OR rose bengal staining > 4 (0–4 score/zone, NEI six zone system, 24 maximum), or Schirmer I test without anesthesia < 5 mm in 5 minutes.
Results: :
Based on the above diagnostic criteria, 94 of the 109 subjects screened were classified as dry and 15 as normal. Repeatability data were available for 64 of the 94 dry eye subjects. Of the dry eye subjects, the Visit 1 mean (± SD) was 11.3 (± 3.7) on the 0– 24 point scale and the Visit 2 (repeatability) mean was 10.3 (± 3.4). The Intra Class Correlation Coefficient was 0.70, demonstrating fair repeatability over a short (1–5 days) time frame. Moreover, the Visit 1 mean score was significantly different compared to the normal score (mean 6.4 ± 2.9); p < 0.001, 2–sample t–test.
Conclusions: :
The modified Schein questionnaire is efficient and appears useful in discriminating normal patients from those with clinically diagnosed dry eye. In addition, the questionnaire appears to yield repeatable scores, suggesting usefulness as a measure of management effectiveness.
Keywords: cornea: tears/tear film/dry eye • cornea: clinical science • clinical (human) or epidemiologic studies: systems/equipment/techniques