Excimer laser trabeculotomy: a new, minimally invasive procedure for patients with glaucoma

Abstract

Excimer laser trabeculotomy (ELT) ab interno is a new surgical technique to reduce intraocular pressure (IOP) in patients with glaucoma or ocular hypertension. Our purpose was to examine IOP reduction and the use of antiglaucoma drugs (AGD) in patients treated with ELT and to evaluate the safety of this laser treatment. To increase the outflow of aqueous humor, ten microperforations of the trabecular meshwork were performed by an endoscope-guided photoablative laser probe (Excimer laser, AIDA, TUI-Laser, Munich; pulse energy: 1.2 mJ at fiber tip, pulse duration: 60 ns, repetition rate: 20 Hz). Average operation time usually was about 2 min. In our pilot study, one group of patients without cataract underwent ELT, the other group with cataract underwent phacoemulsification (PHACO) plus ELT. IOP, visual acuity, and AGD were determined preoperatively (T0) and 2-4 months (T1), 5-7 months (T2), 11-13 months (T3), and 22-26 (T4) months after surgery. Treatment was defined to be successful if (1) postoperative IOP was < or =21 mmHg, and (2) IOP reduction was at least 20%. ELT reduced the IOP from 24.1+/-0.7 (n=69) mmHg preoperatively to 18.8+/-0.4 (T1, n=66), 20.0+/-0.5 (T2, n=51), 18.8+/-0.8 (T3, n= 37), and 16.8+/-1.0 (T4, n=15) mmHg, respectively. However, 28% of the eyes needed repeat surgery due to insufficient IOP reduction. According to Kaplan-Meier statistics, the success rate was 60% (T1), 49% (T2), and 46% (T3), respectively. The number of AGD was 1.9+/-0.1 (T0), 1.2+/-0.2 (T1), 1.3+/-0.2 (T2), 1.8+/-0.2 (T3), and 1.5+/-0.3 (T4). Combined phacoemulsification plus ELT reduced the IOP from 22.4 mmHg+/-0.6 (T0, n=57) to 16.5+/-0.4 (T1, n=52), 16.1+/-0.5 (T2, n= 40), 16.4+/-0.4 (T3, n= 35), and 12.8+/-1.5 (T4, n=4) mmHg, respectively; 7% of the eyes treated with the combined procedure needed repeat surgery due to insufficient IOP reduction. According to Kaplan-Meier statistics, the success rate was 85% (T1), 74% (T2), and 66% (T3), respectively. The number of AGD was 1.1+/-0.2 (T0), 0.9+/-0.2 (T1), 1.1+/-0.2 (T2), 1.2+/-0.2 (T3), and 1.8+/-0.9 (T4). ELT, especially in combination with phacoemulsification, is a new, promising, minimally invasive laser treatment to reduce IOP for at least 1-2 years. ELT alone is less effective in IOP reduction.