Changes in Meibomian Glands May Signal Thyroid Eye Disease

In vivo confocal microscopy can be used to view microstructural changes in the meibomian glands of patients with thyroid eye disease (TED), research published in BMC Ophthalmology shows. The findings provide a strong link between obstruction, inflammation, and the disease.

Ocular surface impairments, including conjunctival hyperemia and chemosis, dry eye, superficial punctate keratopathy, exposure keratopathy, and corneal ulcer, are common in patients with TED. According to researchers, dry eye disease is the most common cause of ocular discomfort found in patients with TED. Previous research reported that eye discomfort and deterioration of the ocular surface in patients with TED might be related to meibomian gland dysfunction. The condition is a major risk factor for evaporative dry eye.

Investigators used in vivo confocal microscopy (IVCM) to evaluate microstructural changes in the meibomian glands in patients with active and inactive TED. In the study, 40 patients (80 eyes) with TED (34 eyes with active TED, 46 eyes with inactive TED), and 31 age- and sex-matched control participants (62 eyes) were enrolled consecutively. A researcher recorded the clinical activity score (CAS) for each patient, and a complete ophthalmic examination was then performed. IVCM of the meibomian glands was performed to determine meibomian gland acinar density (MAD), longest and shortest diameters (MALD and MASD), orifice area (MOA), acinar irregularity (MAI), meibum secretion reflectivity (MSR), acinar wall inhomogeneity (AWI), acinar periglandular interstices inhomogeneity (API), and severity of fibrosis (MF).

All confocal microscopy assessments of meibomian glands significantly differed among the groups (all P =.000), according to researchers. Compared with controls, TED groups showed lower MOA (1985.82±1325.30 μm² in active TED and 2021.59±1367.45 μm² in inactive TED vs 3896.63±891.90 μm² in controls, all P =.000) and MAD (87.21±32.69 mm² in active TED and 80.72±35.54 mm² in inactive TED vs 114.69±34.90 mm² in controls, P =.001 and P =.000, respectively). Additionally, they observed greater MALD (118.11±30.23 μm in active TED and 120.58±27.64 μm in inactive TED vs 58.68±20.28 μm in controls, all P =.000) and MASD (44.77±19.16 μm in active TED and 46.02±20.70 μm in inactive TED vs 27.80±9.90 μm in controls, all P =.000) and higher degrees of MAI, MSR, and MF (all P <.05). Eyes with active TED had higher degrees of MAI (P =.015), AWI (P =.000), and API (P =.000), while eyes with inactive TED had higher degrees of MSR (P =.000) and MF (P =.017). In TED groups, AWI and API were positively correlated with CAS (r=0.640, P =.000; r=0.683, P =.000, respectively), and MF was negatively correlated with CAS (r=-0.228, P =.042).

Investigators note some limitations with their study, including that confocal microscopy analysis was only performed on the inferior eyelid margin, the control group did not represent a healthy population, and LLT was designated as 100 nm for eyes with LLT >100 nm, which may have caused an underestimation of the average LLT value.

Reference

Cheng S, Yu Y, Chen J, et al. In vivo confocal microscopy assessment of meibomian glands microstructure in patients with Graves’ orbitopathy. BMC Ophthalmol. Published online June 19, 2021. doi:10.1186/s12886-021-02024-z