[Filtering surgery in glaucoma: comparative study of three surgical approaches].

Introduction: The multiple complications observed with trabeculectomy encouraged the re-emergence of non penetrating glaucoma surgery (NPGS) in the 1980's. Since then, several modifications have been developed in order to improve success rates and safety. We describe a new variation of deep sclerectomy (DS) in which we include an autologous corneal stromal implant soaked in mitomycin C and sutured to the scleral bed. Next, we compare intraocular pressure (IOP) at 2 years in three groups: I: DS; II: DS with autologous implant soaked in mitomycin C; III: conventional trabeculectomy.

Patients And Methods: All surgeries were performed by the same surgeon. There were 40, 22 and 15 eyes with medically uncontrolled primary open angle glaucoma (POAG) in groups I, II and III, respectively. All patients underwent the usual pre- and postoperative exams over 24 months. Selected patients underwent Visante OCT (Optical Coherence Tomography) (Carl Zeiss, Meditec, Inc. Germany) examination of their anterior segments.

Result: Age and sex distribution in all three groups showed no statistical difference. Mean preoperative IOP was 24 ± 11 mmHg, 26 ± 14 mmHg and 25 ± 9 mmHg in group I, II and III, respectively (P>0.8). Mean postoperative IOP was 14 ± 3 mmHg, 10 ± 3 mmHg and 13 ± 4 mmHg (P=0.05) at six months; 16 ± 4 mmHg, 13 ± 3 mmHg and 11 ± 4 mmHg (P=0.02) at 12 months; and 15 ± 4 mmHg, 12 ± 3 mmHg and 14 ± 4 mmHg (P=0.2) at 24 months. Mean number of eye medications dropped from 1.85, 2.18 to 1.92 (P>0.05) preoperatively in group I, II, and III, respectively, to and 0.25, 0.05 to 0.18 (P=0.02) at 24 months. Patients with a visible implant under the bleb at 24 months had a better outcome.

Discussion: DS with autologous implant significantly reduced IOP at 12 and 24 months. The results seem better than those obtained with collagen implants, most likely due to the persistence of the corneal implant under the bleb at 2 years. Its non-resorption and the minimal fibrosis at the level of the scleral bed may be related to the fact that it is an autologous material which has been soaked with mitomycin C.

Conclusion: DS with autologous implant soaked in mitomycin C, an inexpensive technique, demonstrates medium-term efficacy in the surgical management of POAG. Our results suggest that our technique may enhance both success rate and efficacy in lowering IOP. Further long-term studies are needed.