Impact of Pterygium on Dry Eye and Meibomian Gland Parameters: A Case- Control Study

Purpose To investigate the impact of pterygium on dry eye parameters and meibomian gland morphology and function in a Nepalese population. Methods In this hospital-based case-control study 32 patients with pterygium (Group 1) and 32 age- and sex-matched healthy controls (Group 2) were studied at Bharatpur Eye Hospital, Nepal. Ocular Surface Disease Index (OSDI) scores, Schirmer II test, fluorescein tear film break-up time (TBUT), non-invasive tear break-up time (NIBUT), lipid layer thickness (LLT), and infrared meibography-based meiboscores were recorded and compared between groups. Results In this study, thirty-two eyes with pterygium (Group 1) and 32 control (Group 2) were analyzed. OSDI scores did not differ significantly between groups (16.4 ± 7.7 vs. 13.0 ± 7.5; p = 0.08). However, Schirmer II test values (7.03 ± 3.86 vs. 11.5 ± 6.83 mm; p = 0.002), NIBUT (6.38 ± 3.30 vs. 9.38 ± 4.43 s; p = 0.003), TBUT (5.09 ± 2.69 vs. 9.69 ± 4.16 s; p < 0.001), and LLT (45.0 ± 13.7 vs. 68.2 ± 18.0 nm; p < 0.001) were all significantly lower in Group 1. Meibomian gland loss was significantly greater in the upper (35.2 ± 10.2% vs. 29.1 ± 12.0%; p = 0.034) and lower tarsal plates (29.6 ± 10.3% vs. 24.2 ± 9.14%; p = 0.029) in the pterygium group. Conclusion Meibomian glands tend to show both morphological and functional alterations in eyes affected by pterygium. Also, pterygium is associated with significant impairment of aqueous tear production, tear film stability, lipid layer integrity, and meibomian gland structure. The correspondence between the location of pterygium and meibomian gland abnormality suggests a direct mechanical relationship. Therefore, in the clinical management of patients with pterygium, the presence of meibomian gland dysfunction and evaporative dry eye disease should be carefully evaluated and considered.