A novel technique of ab interno glaucoma surgery:: follow-up results after 24 months

Purpose: It was the aim of this study to investigate the efficacy, longevity, and safety of a new ab interno intervention for the treatment of primary open-angle glaucoma (POAG). Methods: The previously described method of radiofrequency-mediated "sclerothalamotomy ab interno" was applied in 53 eyes of consecutive patients with POAG between April 2002 and July 2002. Average preoperative intraocular pressure (IOP) was 25.6 +/- 2.3 mmHg (range 18-48 mmHg). Sclerothalamotomies were carried out with a custom-made high-frequency dissection 19 G probe (tip 0.3x1 mm) applying bipolar current with a frequency of 500 kHz (tip temperature 130 degrees C). Results: After a follow-up period of 24 months, the average IOP was 15.0 +/- 1.6 mmHg (range 11-20 mmHg) (p < 0.005). The average number of topical agents was 2.6 +/- 1.0 (range 1-5) preoperatively. Twenty-four months after surgery such agents were used in only five (9.6%) eyes and the average was 0.21 +/- 0.53 (range 0-2). Transient IOP elevation was observed in 12 of 53 eyes (22.6%) postoperatively. In all cases elevated IOP could efficiently be controlled with topical medication. In general, IOP dropped continuously over the course of the 6 months following surgery and then remained constant. Conclusions: This study indicates that sclerothalamotomy ab interno is a safe and efficient surgical method for the treatment of POAG. Long-term results clearly demonstrate the longevity of IOP reduction.