Comparison of Mitomycin C Trabeculectomy and Ahmed Valve Implant Surgery for Neovascular Glaucoma

PURPOSE: To compare the results of mitomycin C trabeculectomy and Ahmed valve implant surgery for neovascular glaucoma (NVG). METHODS: We reviewed the medical records of 58 patients (66 eyes) with NVG who had undergone mitomycin C trabeculectomy or Ahmed valve implant surgery in the previous 5 years. Trabeculectomy (A group) was performed in 27 eyes of 24 patients and valve implant surgery (B group) in 39 eyes of 34 patients. Intraocular pressure (IOP), visual acuity, complications and the rate of surgical success of the two groups were compared. IOP under 21 mmHg without medication was considered as complete success (CS), under 21 mmHg with medication as qualified success (QS), and IOP over 22 mmHg despite medication as failure (F). RESULTS: IOP at postoperative 2 months was lower in the trabeculectomy group than in the drainage implant surgery group (16.4 +/- 11.3 mmHg, 20.9 +/- 8.7 mmHg, P=.087), but at 12 months, there was no statistically significant difference (18.4 +/- 11.5 mmHg, 17.0 +/- 6.4 mmHg, P=.608). Visual acuity also showed no significant difference. The respective rate of success between A and B groups was 66.7% and 38.5% (CS), 25.9% and 33.3% (QS), and 7.4% and 28.2% (F), at postoperative 2 months, and 47.8% and 42.3% (CS), 30.4% and 46.2% (QS), and 21.7% and 11.5% (F), at 12 months. The most common postoperative complication was hyphema in both groups, while other complications were shallow anterior chamber, valve problems, etc. CONCLUSIONS: The type of surgery had no significant effect on the success rate of neovascular glaucoma treatment at postoperative 12 months.

The Results and Prognostic Factors of Mitomycin C Trabeculectomy in Neovascular Glaucoma / 영남의대학술지

BACKGROUND: Neovascular glaucoma is common secondary glaucoma at high risk for failure of glaucoma filtering surgery. Recently, trabeculectomy with adjunctive mitomycin C trabeculectomy has been tried to improve the surgical success rate of conventional trabeculectomy. But, the long-term effects of mitomycin C trabeculectomy for neovascular glaucoma are unknown. Thus, we evaluated the long-term effects of mitomycin C trabeculectomy and its prognostic factors influencing the outcome. MATERIALS AND METHODS: Medical records of 62 eyes of 55 neovascular glaucoma who had undergone mitomycin C trabeculectomy were retrospectively reviewed. Surgical success was defined as intraocular pressures of 21 mmHg or less with or without glaucoma medications and no loss of light perception. Surgical failure was defined as postoperative loss of light perception in patients with preoperative vision better than light perception, additional glaucoma surgery, or phthisis bulbi in patients with preoperative vision of no light perception. RESULTS: Postoperative success was obtained in 37 (60%) out of 62 eyes after mean follow- up period of 23.9+/-16.2 months. Using Kaplan-Meier survival analysis, cumulative success rate at the 6-, 12-, 24- and 36-month intervals were 85%, 71%, 57% and 52%, respectively. Success rate was greater in eyes with diabetic retinopathy than other causes(p=0.005) and in eyes with preoperative panretinal photocoagulation(PRP) than without PRP(p=0.015). However, Cox proportional hazard regression analysis revealed that preoperative PRP was not a significant risk factor for surgical failure. CONCLUSION: Prognosis of neovascular glaucoma caused by diabetic retinopathy was better than that caused by the other disorders following mitomycin C trabeculectomy. The author would suggest that mitomycin C trabeculectomy could be effective and relatively safe as the first procedure of choice before performing glaucoma drainage device implantation or cyclodestructive procedure.