Correlating corneal and meibomian gland morphology with diabetes duration in T2DM via confocal microscopy

To investigate morphological changes in the cornea and meibomian glands using in vivo confocal microscopy (IVCM) in patients with type 2 diabetes (T2DM) and to analyze the correlation of these changes with disease duration (DD).

Patients with T2DM who visited the ophthalmology and endocrinology departments of our hospital from May 2023 to December 2023 were selected. According to DD, they were divided into the short-DD (≤10y) and long-DD (>10y) groups. The control group consisted of age-matched non-diabetes patients. All underwent Ocular Surface Disease Index (OSDI), tear break-up time (TBUT), Schirmer I test (SIT), and IVCM imaging. Corneal nerve parameters, including corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and meibomian gland metrics, including density of meibomian gland acinar units (MGAUD), the longest diameter of the meibomian gland acini (MGALD), the shortest diameter of meibomian gland acini (MGASD), the area of meibomian gland acinar units (MGAUA), were analyzed using ImageJ and ACCMetrics.

A total of 130 patients with T2DM were included in this study, among which 68 were male (52.3%, age 30-76y) and 62 were female (47.7%, age 30-76y), the average age of the group was 55.54±11.65y. Significant differences (P<0.001) were observed in OSDI, TBUT, SIT, CNFD, CNBD, CNFL, MGALD, MGASD, MGAUD, and MGAUA between diabetes groups and controls. DD positively correlated with OSDI, MGALD, and MGASD (P<0.05), and negatively correlated with TBUT, SIT, CNFD, and CNFL (P<0.05). No correlation was found between DD and CNBD, MGAUD, or MGAUA (P>0.05).

T2DM patients exhibit greater corneal nerve and meibomian gland damage than age 30-76y non-type 2 diabetes patients. Prolonged DD exacerbates these morphological changes.