Objective: To determine the effect of long-term topical antiglaucoma therapy on the results of glaucoma filtration surgery and to relate any differences to the cell population profile of the conjunctiva.
Methods: Filtration surgery was performed in 124 patients (trabeculectomy in 112 and triple procedures [trabeculectomy, cataract extraction, and intraocular lens implantation] in 12), and the outcome of these procedures was assessed after a minimum follow-up of 6 months. A conjunctival biopsy specimen was obtained at the time of surgery. The patients were divided into four groups according to the type of topical therapy administered. The duration of therapy tended to be greater for the patients treated with a greater number of medication types. The outcome of trabeculectomy was assessed in 106 of the patients.
Results: In comparison with the briefly treated-primary surgery group, the success rate of trabeculectomy (90% [n = 28]) was similar to that in the group treated with beta-blockers (93% [n = 29]). The trabeculectomy success rate for patients treated with beta-blockers and miotics was significantly lower (72%, P < .01 [n = 29]), and that for the group treated with beta-blockers, miotics, and sympathomimetics was even lower (45%, P < .001, [n = 20]).
Conclusions: Various treatment regimens were associated with differential effects on the success rate of trabeculectomy. Long-term topical combination therapy was identified as a significant risk factor for failure of trabeculectomy. Preoperative conjunctival cell counts from patients whose trabeculectomies were successful were compared with those whose trabeculectomies failed. Failure was associated with significantly more pale cells (P < .01), macrophages (P < .05), and lymphocytes (P < .05) in the epithelium; fibroblasts (P < .05) and macrophages (P < .05) in the superficial substantia propria; and both macrophages and lymphocytes in the deep substantia propria (P < .01). Thus, preoperative subclinical conjunctival inflammation induced by previous topical medication was identified as a risk factor for failure of trabeculectomy.