The Effect of Subconjunctival Retention of Perfluoropropane Gas on the Success Rates of Trabeculectomy in Rabbits

PURPOSE: This study was aimed to evaluate the effect of subconjunctival retention of perfluoropropane gas on the success rates in trabeculectomized rabbits. METHODS: Fifthteen white rabbits were trabeculectomized by fornix-base conjunctival flap, full thickness sclerotomy and iridectomy. The right eye was control and the left eye was injected with 0.2 ml perfluoropropane gas(C3F8) into subconjunctival space through the 30 guage long needle. Each rabbit was examined for bleb morphology under slit-lamp microscope and measured for intraocular pressure by tonopen at preoperative, postoperative 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks. The results were analyzed by Wilcoxon rank sum test in SAS release 6.12 program. RESULTS: Mean gas retention time was 15+/-2 days. Intraocular pressure measured at postoerpative 2 weeks was statistically significantly lower in gas injected group than control group. At postoperative 2 weeks, fibrovascularization was more prominent in control group than gas injected group. Fibroblast proliferation and collagen tissue formation were more prominent in control group than gas injected group at postoperative 6 weeks. CONCLUSIONS: Subconjunctival perfluoropropane gas(C3F8) bubbles, via "spacer" effect, aid the maintenance of filtering blebs in the early postoperative period. This technique may be useful in augmenting or salvaging blebs at high risk of failure.

A Comparative Analysis of Dynamic Strategy and Normal Strategy in Octopus 101 Perimeter

Dynamic strategy(DS) is a fast threshold algorithm for the Octopus 101 perimeter. To analyze the efficiency of DS, we compared the results of visual field measurements using DS and conventional normal strategy(NS). Subjects comprised 60 eyes of 30 normal individuals in the 3rd decade who has not experienced perimetry before. Program G2 was performed on all subjects at random and enough intervals between the two tests(more than 1 hour). Mean testing time was 1047.63+/-219.38 seconds in NS and 684.98+/-130.95 seconds in DS. Testing time reduction rate was 32.69+/-14.35% on average. Mean defect(MD) was 2.80+/-1.02dB, 2.15+/-0.94dB in the two strategies, respectively. Corrected loss variance(CLV) was 1.31+/-0.50dB2 and 1.03+/-0.61dB2 in each test. There was significant difference in MD and CLV statistically(P0.01). It took less time with DS than NS in Octopus 101 perimeter, but further study will be needed for clinical application of DS.