Ultrasonography assessments of meibomian gland as a noninvasive method of detecting changes in morphology

Purpose

We employed 24 MHz ultrasonography to evaluate the morphological features of meibomian glands (MGs) and compared the ultrasonic differences in morphology between healthy volunteers and meibomian gland dysfunction (MGD) patients.

Methods

24 MHz ultrasound examinations on both the upper and lower eyelids of healthy volunteers and patients with MGD, using transverse and longitudinal sections. The reproducibility of ultrasonographic findings for the MG was evaluated, and a comparison of morphological characteristics at different examination sites between the two groups was made.

Results

Among 89 participants, 24 were healthy volunteers and 65 had MGD. The cross-sectional ultrasound findings showed well-organized punctate hyperechoic ducts within the tarsal plate, surrounded by hypoechoic acinar formations, which were further classified based on the extent of MG involvement into three categories: normal, ≤50 % involvement, and >50 % involvement. Additionally, a typical longitudinal ultrasound appearance of a MG consisted of a thin band-like hypoechoic structure (acinar) with uniform thickness accompanied by an arc-shaped linear hyperechoic duct in its middle region. Furthermore, seven abnormal longitudinal ultrasound manifestations were categorized as distortion, ectasia, central duct truncation, cyst formation, structureless appearance, complete disappearance or other findings. The intra- and inter-observer agreement for those categories was found to be high (ICC>0.6). MGD patients exhibited a higher likelihood of overall MG involvement or abnormal ultrasound findings, particularly in relation to the middle part of the upper eyelid.

Conclusion

The present study has developed an initial classification method to identify abnormalities in MG morphology using 24 MHz ultrasound in MGD patients.