Diagnostic value of tear hyperosmolarity in dry eye

Abstract

Background Tear hyperosmosis is considered to be one of the core mechanisms of dry eye.The measurement of tear osmolarity is important in the clinical diagnosis of dry eye.However, relevant study is lack in Chinese population. Objective The aim was to investigate the relation of tear osmolarity and pathogenesis of dry eye and evaluate the diagnosis value of tear hyperosmosis in dry eye. Methods Sixty-one consecutive dry eye patients were enrolled in Affiliated Eye Hospital of Wenzhou Medical University from May to August in 2011, including 30 mild and moderate dry eyes and 31 severe dry eyes, and 30 normal volunteers with matched age and gender were collected simultaneously under the informed consent.The visual acuity, Ocular Surface Disease Index (OSDI) questionnaire, osmotic pressure of tear, tear film breakup time (TFBUT), corneal fluorescein staining, conjunctival lissamine green staining, ShirmerⅠtest (SⅠt) without anesthesia and meibomian function were examined in turn in the subjects, and lateral eyes with higher tear osmotic pressure were analyzed.The differences in above indexes among the different groups were statistically compared, and the correlations between the osmotic pressure of tear and clinical parameters were assessed. Results The osmotic pressure of tear was (326.46±22.66) mOsm/L in the dry eye group, which was significantly higher than (296.60±10.81) mOsm/L in the normal control group (P 0.05). Conclusions Tears osmotic pressure might be a useful indicator for the diagnosis of dry eye and assessment of severity.A combined application of tear osmolarity measurement with other relevant indexes can improve the diagnostic value. Key words: Dry eye/diagnosis; Tears; Osmolar concentration; Diagnostic techniques, ophthalmological/instrumentation