Milling trabeculoplasty for nonpenetrating glaucoma surgery.

PURPOSE: To describe the use of a motorized milling drill to perform nonpenetrating glaucoma surgery and to assess its safety.

SETTING

Instituto Oftalmológico de Alicante, Miguel Hernandez University, School of Medicine, Alicante, Spain.

METHODS

This prospective noncomparative study included 16 eyes (13 patients) diagnosed with primary open-angle glaucoma. The eyes were divided into 2 groups. Group 1 (8 eyes) had a milling procedure, and Group 2 (8 eyes) had combined phacoemulsification and milling. A fornix-based conjunctival flap was created, and then the milling procedure was performed using a notched hemispherical metallic tip. Evolution of intraocular pressure (IOP), visual outcomes, and the development of intraoperative and postoperative complications were evaluated.

RESULTS

The mean age of the patients was 67.9 years +/- 10.9 (SD) (range 50 to 80 years). In Group 1, the mean IOP preoperatively was 27.6 +/- 10.1 mm Hg (range 18 to 50 mm Hg) and after 6 months, 15.8 +/- 5.2 mm Hg (range 12 to 24 mm Hg). The mean IOP reduction 6 months postoperatively was 15.4 +/- 10.6 mm Hg, a 55.7% decrease from preoperatively. In Group 2, the mean IOP preoperatively was 21.7 +/- 4.6 mm Hg (range 13 to 30 mm Hg), and after 6 months, 16.2 +/- 3.4 mm Hg (range 13 to 23 mm Hg). The mean reduction in IOP at 6 months was 5.5 +/- 2.8 mm Hg, a decrease of 25.3% from the preoperative value. In Group 1 at 6 months, 5 eyes (62.5%) had a diffuse filtering bleb and 3 (37.5%), localized filtration. In Group 2, 7 eyes (87.5%) had a diffuse filtering bleb and 1 (12.5%) had fibrosis of the bleb and reduction of filtration.

CONCLUSION

The motorized milling drill can be safely used to mill and refine the remaining scleral thickness, eliminating the rupture of trabeculo-Descemet's membrane.