HOW SUCCESSFUL IS NEEDLING OF THE FAILED FILTERING BLEB

Background ''Needling'' may become necessary when filtering blebs fail due to scarring or encapsulation. Our goal was to calculate the mediu m term success rate of the needling procedure. Methods The results of 90 needling procedures performed on 58 eyes were analyzed. 52 eves req uired one single needling (group 1) after simple trabeculectomy, where as 19 eyes had to have double needling (group 2) and 3 eyes had to be needled 3 times (group 3). These figures do not include a 4th group of 16 eyes which had been needled after repeated and complicated surgery . Success rates were calculated at t(1) = 0-1 day, t(2) = 1-4, weeks, t(3) = 4-8 weeks, t(4) = 3-5 months and t(5) = > 6 months after the tr eatment. Results The mean IOP (n = 90) was Results The mean IOP (n = 9 0) was 29 +/- 6 mmHg preoperatively. 15 +/- 10 mm Hg at t(1), 23 +/- 9 mm Hg at t(2), 20 +/- 7 mm Hg al t(3), 17 +/- 5 at 4 and 17 +/- 3 at t(5). The overall success rates were 80% (t(1)), 45% (t(2)), 37% (t(3) ), 35% (t(4)) and 31% (t(5)). The corresponding responding success rat es were 74%, 36%, 32%, 28% and 26% for group 1, 89%, 52%, 37%, 37% and 31% for group 2. 67% at all times for group 3 and 100%, 69%, 54%, 54% and 45% for group 4. Conclusions In one third of all cases the needli ng is effective for more than 6 months. A complicated pressure lowerin g surgery does not necessarily diminish the effectiveness of a needlin g procedure. Re-needlings are as successful as the first one.