Abstract
Purpose :
The etiology of meibomian gland dysfunction (MGD) remains unclear. We assessed the association between the commensal microflora of the eyelid margins and meibomian gland (MG) function in a normal population.
Methods :
Subjects (184), aged from 25 to 66 years with no systematic conditions, pre-existing ocular irritation, injury or infection were recruited in the study. Ocular swabs were taken from the lower lid margin of the left eye. Conventional cultivation techniques were used for isolation and identification of bacteria. Meibum quality (MQ) (0: clear and 4: no meibum expressed) and MG expressibility (MGE, 0: all glands expressible and 3: severely affected) of lower eyelid were graded following TFOS MGD workshop guidelines. The association between microorganism counts and meibomian gland functional grading was assessed.
Results :
The population comprised 96 younger (aged 25 to 44; 60 female and 36 male) and 88 older subjects (aged 45 to 66; 48 female and 40 male). Number of microorganisms isolated ranged from 0 to 1500 cfu per swab. The most commonly identified microorganisms were commensal skin bacteria including Propionibacterium (59%), and Staphylococcus epidermidis (36%). Average bacterial counts from the eyelids were higher in males than females overall (162±156 vs. 105± 187 cfu per swab; p < 0.05) and in older females compared to younger (155 ± 187 vs. 64 ± 82 cfu per swab, p < 0.05). Higher counts were enumerated from subjects with an MQ Grade 4 (no meibum expressed) compared to the MQ grade 0 (clear) (289 ± 222 vs 81 ± 104 cfu per swab; p < 0.05). When segregated by gender, this held true for females but not males. Similarly for females only, gland expressibility of ‘severe’ (Grade 3) was associated with higher bacterial counts compared to ‘all glands expressible’ (Grade 0) (401 ± 229 cfu per swab vs 91± 124 cfu per swab, p < 0.05). Younger men had higher average cfu than older men (183 ± 160 cfu per swab vs 144 ± 1151 cfu per swab; p < 0.05).
Conclusions :
Increased number of commensal bacteria obtained from the lower eyelid was associated with clinical measures of decreased meibum quality and MG expressibility. Younger females had lower bacterial counts associated with a better meibomian gland function compared to older females. It remains to be determined if this increased commensal bacterial burden plays a direct role in the establishment of MGD.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.