Correlation between filtering bleb morphology, expression of inflammatory marker HLA-DR by ocular surface, and outcome of trabeculectomy.

PURPOSE: To correlate clinical bleb characteristics and the expression of human leukocyte antigen (HLA)-DR by conjunctiva with the outcome of trabeculectomy.

PATIENTS AND

METHODS

In this cross-sectional study, bleb morphology was assessed at slit lamp using the Moorfields Bleb Grading System in 85 eyes of 85 patients. Conjunctival specimens were collected from superior conjunctiva by impression cytology and analyzed for the expression of HLA-DR on epithelial and antigen-presenting cells. The success of trabeculectomy was defined as intraocular pressure <21 mm Hg without antiglaucoma drops. Differences in bleb characteristics and expression of HLA-DR between eyes with surgical success and failure were examined.

RESULTS

Fifty-eight of 85 eyes with successful trabeculectomy had significantly greater central and maximal area of the bleb (P<0.001) with decreased vascularity of the central (P=0.02) and peripheral part of the bleb (P=0.03). The expression of HLA-DR on conjunctival epithelial cells and antigen-presenting cells was not different between the eyes with successful and failed trabeculectomy and also not between the eyes with and without topical glaucoma medication or topical corticosteroid eye drops.

CONCLUSIONS

Successful trabeculectomy was associated with greater area and decreased vascularity of the bleb but not with diminished expression of inflammatory marker by ocular surface. Presence of subclinical inflammation in eyes without eye drops may result from the transcellular aqueous pathway towards the ocular surface, especially in functioning blebs with adjunctive mitomycin C.