Correlation of Dry Eye Workshop Dry Eye Severity Grading System With Tear Meniscus Measurement by Optical Coherence Tomography and Tear Osmolarity

Objectives: To compare tear meniscus measurements obtained by optical coherence tomography (OCT) and tear osmolarity with dry eye severity according to the Dry Eye Workshop (DEWS) classification system. Methods: Forty-four eyes of 22 patients with dry eye disease (DED) were recruited in this prospective study. In all eyes, ophthalmic examination was performed in the same order as follows: Ocular Surface Disease Index (OSDI) survey, tear film osmolarity measurement with TearLab Osmolarity System, tear meniscus measurements by OCT, corneal fluorescein staining scoring, conjunctival lissamine green staining scoring, tear film breakup time assessment, and anesthetized Schirmer test. Dry eye disease severity was graded according to the DEWS dry eye severity grading system, and the patients were divided into two groups. Group 1 composed of the patients with grades 1 and 2 DED, and group 2 composed of the patients with grades 3 and 4 DED. Results: The mean tear osmolarity value was significantly higher in group 2 (318.9 +/- 12.8 mOsm/L) than in group 1 (308.1 +/- 8.5 mOsm/L) (P<0.01). The mean tear meniscus height (TMH), tear meniscus depth (TMD), and tear meniscus area (TMA) values were significantly lower in group 2 (172.9 +/- 73.5 mu m, 121.57 +/- 46.2 mu m, and 0.013 +/- 0.012 mm(2), respectively) than in group 1 (218.5 +/- 70.2 mu m, 157.94 +/- 49.1 mu m, and 0.022 +/- 0.013 mm(2), respectively) (P=0.05, P=0.02, and P=0.026, respectively). There was a negative correlation between TMH and OSDI at the level of 45% (r=-0.450; P<0.05), between TMD and OSDI at the level of 47% (r=-0.470, P<0.05), and lastly between TMA and OSDI at the level of 48.5% (r=-0.485, P<0.05). There was no correlation between OSDI and tear osmolarity (P>0.05). Conclusions: Both tear osmolarity and tear meniscus OCT measurements comply with the DEWS grading system, and they can be used in the diagnosis and follow-up of dry eye patients in addition to conventional tests.