Purpose: To evaluate the distribution of meibomian gland dropout and analyze the correlation between dropout and meibomian gland dysfunction (MGD).
Methods: A total of 161 eyes of 85 patients with MGD were recruited as the MGD group; 88 eyes of 46 health volunteers were enrolled as the control group (2:1 matched for age and sex). Examinations included the Schirmer I test, breakup time, symptom questionnaire, corneal fluorescein staining, meibum quality, meibomian gland expressibility, and meibomian gland dropout.
Results: (1) The incidences of chalazion and eyelid surgery were significantly higher in patients with MGD. (2) All clinical indexes were better in healthy volunteers (all P < 0.05). (3) The dropout in the upper eyelid was statistically lower (P < 0.01) in both groups. The nasal and/or temporal part had higher dropout than did the middle part, except in the lower eyelid of the control group. (4) The entire or partial dropout was positively related to MGD occurrence. Both additive dropout of the entire 2 eyelids and that of the 2 nasal parts had the strongest correlation (r = 0.792, P < 0.01). (5) In the MGD group, breakup time was most negatively related to upper nasal dropout (r = -0.229, P < 0.05). The corneal staining score was positively related only to the dropout of additive (r = 0.185, P < 0.05) and lower (r = 0.258, P < 0.05) middle parts.
Conclusions: (1) Uneven dropouts exist in different or single eyelids. (2) Dropout evaluation is better when covering the entire area of both upper and lower meibomians. (3) Nasal part dropout plays a more essential role than the other dropouts in MGD occurrence.