Association Between Tear Osmolarity and Dry Eye Signs in Patients with Obstructive Meibomian Gland Dysfunction

Purpose: To explore the correlations between tear osmolarity, as measured using I-PEN® (I-MED Pharma, Inc., Dollard-des-Ormeaux, QC, Canada), and various dry eye indicators, including the Schirmer test, tear break-up time (TBUT), Oxford scale, and Ocular Surface Disease Index (OSDI), in patients with obstructive meibomian gland dysfunction (MGD).Methods: The medical records of 44 cases of obstructive MGD were reviewed. Tear osmolarity was obtained using I-PEN® (I-MED Pharma, Inc.). The TBUT, Schirmer test, Oxford scale, OSDI, and MGD grade were used to assess the cases, and their correlations with tear osmolarity were analyzed.Results: Spearman and Pearson correlation analyses showed a significant correlation between tear osmolarity and MGD grade (p < 0.001) and OSDI (p = 0.005). However, the results of the TBUT, Schirmer test, and Oxford scale were not significantly related to tear osmolarity. The patients were divided according to MGD severity into those with MGD grades ≤ 2 and those with MGD grades ≥ 3. Tear osmolarity (p < 0.001) and OSDI (p = 0.014) showed significant differences between the two groups.Conclusions: In patients with obstructive MGD, tear osmolarity, assessed using I-PEN® (I-MED Pharma, Inc.), is significantly correlated with MGD grade and OSDI.