Purpose: To evaluate the safety and effectiveness of glaucoma filtering surgery performed with the adjunctive use of bleomycin administered in conjunction with electric pulses (EP).
Design: Experimental study in rabbits. CONTROLS AND METHODS: Trabeculectomies were performed on pigmented rabbits (2 to 2.5 kg) using the following adjunctive treatments: 5 microM of topical bleomycin and EP (5V, 50 msec, 8 pulses) (group A: B+E+, n=15); bleomycin but no EP (group B: B+E-, n=15); 5 ,uM mitomycin C (MMC) and EP (group C: M+E+, n= 10); MMC but no EP (group D: M+E-, n=10); EP alone (group E: E+, n=10); and no adjunctive treatment (group F: E-, negative control, n=10).
Main outcome measures: Intraocular pressure (IOP) was measured regularly for 60 days after the operation. Bleb formation and the condition of the conjunctiva, cornea, and retina were also regularly evaluated. Histologic studies were performed by light microscopy, and retinal functions were evaluated by electroretinography.
Results: Postoperative IOP was significantly lower than the preoperative level in all the animals until day 7. However, in groups E and F (the negative control) it returned to the preoperative level after day 7, and in groups B, C, and D after 15 days. The IOP of group A remained lower even on day 40. The average amount IOP was lowered or increased on day 20 was -6.4 mmHg (P < 0.05) in group A; -0.2 mmHg in group B; +1.2 mmHg in group C; and -3.25 mmHg in group D. The survival rate of the filtering blebs on day 20 was significantly higher in group A than in the other groups. Clinical and histologic studies uncovered no pathologic findings in any intra- or paraocular tissues. Electroretinographic evaluation of retinal function in group A showed no apparent change over the 60 days of the study.
Conclusion: Glaucoma filtering surgery in rabbits with the adjunctive use of bleomycin in conjunction with EP significantly lowered IOP for up to 40 days without clinically, morphologically, or functionally harming intraocular tissues.