Table 1

Characteristics of the study population

VariableComplete sample
n=3824
Subsample that completed OSDI and self-perceived health question
n=681
Female gender3824 (100%)681 (100%)
Age category (years)
 20–29182 (4.8%)4 (0.6%)
 30–39327 (8.6%)28 (4.1%)
 40–49571 (14.9%)101 (14.8%)
 50–59967 (25.3%)181 (26.6%)
 60–691177 (30.8%)270 (39.6%)
 70–79540 (14.1%)93 (13.7%)
 80–8960 (1.6%)4 (0.6%)
Twin status
 Monozygotic2133 (55.8%)347 (51.0%)
 Dizygotic1691 (44.2%)334 (49.0%)
Ethnicity
 White3766 (98.5%)676 (99.3%)
 Asian9 (0.2%)0 (0.0%)
 Black19 (0.5%)3 (0.4%)
 Mixed24 (0.6%)2 (0.3%)
 Other6 (0.2%)0 (0.0%)
Dry eye disease symptoms last 3 months794 (20.8%)154 (22.6%)
Dry eye disease diagnosis by a clinician437 (11.4%)103 (15.1%)
Current use of artificial tears567 (14.8%)99 (14.5%)
Dry eye disease diagnosis and current use of artificial tears
 Cases367 (9.6%)72 (10.6%)
 Controls3171 (82.9%)551 (80.8%)
  • OSDI, Ocular Surface Disease Index.