Correlation between OSDI Score, Tear Break-Up Time and Schirmer Test in Patients with Dry Eye Disease: A Cross-Sectional Observational Study
Keywords:
Dry Eye Disease; Ocular Surface Disease Index; OSDI; Tear Break-Up Time; TBUT; Schirmer I Test; CorrelationAbstract
Background: Dry eye disease is clinically heterogeneous, and symptom burden does not always parallel individual ocular surface signs. The Ocular Surface Disease Index (OSDI), tear break-up time (TBUT) and Schirmer I test assess complementary dimensions of dry eye, making their relationship relevant to routine evaluation.
Objective: To determine the correlation of OSDI score with TBUT and Schirmer I test values in patients with dry eye disease.
Methods: This cross-sectional observational study enrolled 50 consecutive patients with symptomatic dry eye disease. Dry eye was operationally defined by an OSDI score >=13 together with either fluorescein TBUT <10 seconds or Schirmer I test <10 mm/5 min without anaesthesia. Final eligibility validation identified one enrolled participant who did not meet the objective-test criterion; 49 eligible participants were therefore included in the analysis. Spearman rank correlation was used to examine relationships among OSDI, TBUT and Schirmer I values.
Results: Among 49 eligible participants, mean age was 56.24 ± 11.27 years and 28 (57.1%) were female. Mean OSDI score was 43.22 ± 11.47, mean TBUT was 5.46 ± 2.36 seconds and mean Schirmer I value was 6.74 ± 2.96 mm/5 min. Eleven (22.4%) participants had moderate and 38 (77.6%) had severe disease by OSDI classification. OSDI showed very strong inverse correlations with TBUT (Spearman rho=-0.986, p<0.001) and Schirmer I (rho=-0.988, p<0.001), while TBUT and Schirmer I were very strongly positively correlated (rho=0.993, p<0.001).
Conclusion: In this moderate-to-severe dry eye cohort, greater symptom burden was accompanied by shorter tear-film break-up time and lower Schirmer I values. The exceptionally strong correlations should be interpreted within the restricted clinical spectrum and the limitations of a single-centre cross-sectional study. Combined symptom and objective tear-film assessment remains clinically appropriate.
