Purpose: To evaluate meibomian gland loss after trabeculectomy with mitomycin C (MMC).
Methods: This cross-sectional observational case study involved 55 eyes in 39 patients who had undergone trabeculectomy with MMC administered to the upper area of the eye. We used a mobile pen-shaped noncontact meibography system to access the morphology and determine loss of the meibomian glands. Meibomian gland loss was scored (meiboscore) from grade 0 (no loss of the meibomian glands) through grade 3 (loss of more than two-thirds of the total area) in the bleb-contacting and bleb-noncontacting upper eyelid areas in the primary position and in the lower eyelid. The tear film breakup time (BUT) was also measured.
Results: The median duration from trabeculectomy to examination was 7.4 years (interquartile range 3.1-14.2). The meiboscores of the bleb-contacting upper eyelid areas were significantly higher than those for the bleb-noncontacting upper eyelid areas (P < 0.001). The meiboscores for both the bleb-contacting and the bleb-noncontacting upper eyelid areas were significantly higher when the bleb was avascular (P = 0.011 and P = 0.008, respectively). The meiboscores of the bleb-contacting and bleb-noncontacting upper eyelid areas showed a significant negative correlation with the BUT (r = -0.330, P = 0.014 and r = -0.296, P = 0.028, respectively).
Conclusion: Blebs that occur after trabeculectomy with MMC may be the cause of meibomian gland loss, particularly when the bleb is avascular. The presence of an avascular bleb warrants extra vigilance for decreased meibomian gland secretions because this decrease can lead to tear dysfunction and ocular surface damage, including bleb-wall damage.