Changes in the tear film and meibomian gland morphology between preclinical dry eye and normal subjects represented by ocular surface disease index scores.

Tear film and MG morphology play an essential role in detecting dry eyes and Meibomian Gland Dysfunction (MGD). Previous studies have reported these changes in cases diagnosed with dry eyes. However, it is important to study these changes among subjects with symptoms of dry eyes without signs. Hence, this study evaluated the changes in the tear film and meibomian gland (MG) morphology among subjects with pre-clinical dry eye and compared it with the normals defined by the Ocular Surface Disease Index score. One hundred and fifty subjects were enrolled in this prospective cross-sectional study. All the subjects completed the Ocular Surface Disease Index (OSDI) questionnaire and the Computer Vision Syndrome Questionnaire (CVS-Q). Tear film tests such as non-invasive break-up time (NIBUT), tear meniscus height (TMH), lipid layer pattern, Schirmer's test, and corneal staining were performed. Images were captured from both the upper and the lower eyelids to study the MG morphology. TMH, MG length, thickness, loss, and tortuosity were measured using ImageJ software. Subjects were differentiated into two groups based on an OSDI threshold score of ≥13 as preclinical dry eye and normals. Among all the subjects, 43.6% of them were categorized as pre-clinical dry eye, and 56.4% as normals. In the pre-clinical dry eye group, a significant reduction in NIBUT (Z = -2.13, p = 0.03) and MG length of the lower lid (Z = -2.58, p = 0.01) was found when compared to normals. TMH, Schirmer's test, and MG width did not vary among both groups (p > 0.05). Similarly, MG loss and tortuosity score was higher in the pre-clinical dry eye group, but did not show any statistical significance (p > 0.05). The majority of the young individuals presenting for the regular eye examination may have pre-clinical dry eye based on their OSDI scores. Hence, it is important to administer the OSDI questionnaire and perform non-invasive tests such as NIBUT and IR imaging of MG as a part of the routine eye examination.