LOCAL-EFFECTS OF PREVIOUS CONJUNCTIVAL INCISIONAL SURGERY AND THE SUBSEQUENT OUTCOME OF FILTRATION SURGERY

PURPOSE: Previous ocular surgery involving conjunctival incision is a risk factor for failure of filtration surgery. To determine whether us ing adjunctive antimetabolite therapy may have a rational basis, a stu dy was performed to determine whether the conjunctival cellular profil e was altered by such surgery. METHODS: After a mean follow-up of 5.9 years, filtration surgery outcomes for 35 patients who had undergone c onjunctival incisional surgery were retrospectively compared with 29 c ontrol and 18 matched patients who had not undergone such surgery. At the time of filtration surgery, a conjunctival biopsy specimen was obt ained from all 82 patients, and these were quantitatively analyzed by light microscopy in a prospective manner. RESULTS: Trabeculectomy succ ess for the con trol group (93%) was significantly higher than for the previous surgery group (38%) (P < .001). Compared with control tissue , conjunctiva from the patients who had undergone previous surgery con tained more fibroblasts (P < .001, P < .05), macrophages (P < .01, P < .001), and lymphocytes (P = .001, P < .01) in both superficial and de ep substantia propria (respective P values). Furthermore, trabeculecto my failure was associated with an increase in number of conjunctival f ibroblasts in intraoperative specimens. CONCLUSIONS: Previous ocular s urgery involving the conjunctiva increases the number of conjunctival fibroblasts and inflammatory cells. This may account for the increased risk of trabeculectomy failure. Perhaps on this basis, the use of adj unctive medication may be justified in patients who have undergone pre vious ocular surgery involving conjunctival incision. (C) 1998 by Else vier Science Inc. All rights reserved.).