High-intensity focused ultrasound treatment in patients with refractory glaucoma

Purpose: To assess the safety and efficacy of ultrasound coagulation of the ciliary body in refractory glaucoma. Methods: This prospective multicenter interventional study was conducted in two Italian university-affiliated glaucoma centers: St. Orsola-Malpighi Teaching Hospital (Bologna, Italy) and University Eye Clinic of Genoa (Genoa, Italy). The main inclusion criterion was the diagnosis of glaucoma with a baseline intraocular pressure (IOP) ≥ 21 mmHg while on maximum topical and systemic medical hypotensive treatment. The EyeOP1 device (Eye Tech Care, Rillieux-la-Pape, France), which was employed in the study, uses miniaturized transducers to produce high-intensity focused ultrasound (HIFU). Treatment consisted of the sequential activation of each transducer lasting 4 s (group 1), 6 s (group 2) or 8 s (group 3). Hypotensive medications were interrupted after surgery and then prescribed only if postoperative IOP was ≥ 21 mmHg during follow-up visits. Patients were assessed before and 1, 7, 14, 30, 90 and 180 days after the procedure. Primary outcomes were the mean IOP reduction in the overall population and in groups 1, 2 and 3, and the rates of complete success, qualified success and failure. Results: Thirty eyes (16 open-angle, 10 angle-closure and 4 neovascular glaucoma) of 30 patients were included. The mean preoperative IOP was 30.1 ± 10.5 mmHg. Twenty-nine patients completed the entire study follow-up; one patient exited from the study 3 months after HIFU and underwent trabeculectomy. At days 1 and 180, the mean IOP was significantly reduced (18.4 ± 7.2 and 20.2 ± 6.2 mmHg, respectively; all p < 0.0001). Group 3 patients (8-s ultrasound exposure time) showed a greater IOP reduction than the other two groups (−16.2 ± 8.3 for group 3 vs. −8.8 ± 6.6 for group 2 and −3.7 ± 6.5 for group 1; p = 0.02 and p < 0.001, respectively). Qualified and complete success was achieved in 23.3 and 46.7% of patients, respectively; treatment failure was recorded in 6.6%. Conclusions: Ultrasonic coagulation of the ciliary body is a safe and effective procedure for reducing IOP in refractory glaucoma. The increase in ultrasound exposure time appears to improve the response rate and the global efficacy of the procedure, with no detrimental effect on safety.