Association of a novel meibomian gland dysfunction composite score with corneal nerve parameters and ocular surface...

To construct a composite meibomian gland dysfunction (MGD) score integrating gland dropout, expressibility, and meibum quality, and to investigate its associations with corneal nerve parameters, subjective symptoms, and ocular surface signs in patients with dry eye disease (DED).

This cross-sectional study included 137 DED patients (274 eyes). MGD composite score (0-9) was calculated as the sum of averaged upper/lower eyelid scores for dropout (0-3), expressibility (0-3), and meibum quality (0-3). Corneal nerve parameters (length, width, reflectivity, microneuroma count) were assessed by in vivo confocal microscopy. Symptoms were evaluated using OSDI and a 10-item visual analogue scale. Tear break-up time (TBUT), corneal fluorescein staining (CFS), and tear meniscus height (TMH) were recorded. Correlation, partial correlation (to explore the associational pathway), and subgroup analyses were performed.

MGD composite score positively correlated with OSDI (r = 0.769, p < 0.01) and negatively with corneal nerve fiber length (CNFL) (r = -0.709, p < 0.01). OSDI correlated strongly with CNFL (r = -0.868, p < 0.01). After controlling for nerve length, age, sex, and CFS, the partial correlation between MGD composite score and OSDI dropped from 0.796 to 0.390. Patients with higher MGD grades exhibited significantly shorter nerve length, more microneuromas, worse TBUT, higher CFS, and greater symptom scores (all p < 0.05). Microneuroma count correlated positively with pain, asthenopia, blurred vision, and photophobia.

The MGD composite score effectively reflects disease severity. Corneal nerve length is strongly associated with the relationship between MGD signs and subjective symptoms, providing a structural basis for understanding symptom-sign discordance in DED.