Application of high intensity focused ultrasound for treatment of open-angle glaucoma in Indian patients

Abstract

Purpose: The aim of this study is to assess the efficacy of ultrasound cycloplasty (UCP) in Indian patients with open angle glaucoma (OAG).

Methods: A prospective interventional study was designed to treat 73 eyes of 73 patients with OAG with the EyeOP1 device equipped with six miniaturized cylindrical piezoelectric transducers. Two treatment protocols of ultrasound delivery depending on exposure time (8 s and 10 s of shot per transducer) were used. Complete ophthalmic examination, ocular biometry and anterior segment optical coherence tomography were performed preoperatively and patients were followed up at day 1, day 7 and months 1, 2, 3, 6, and 12. The primary outcome measure was "successful" intraocular pressure (IOP) control defined as IOP reduction ≥20% from baseline and IOP value >5 mm Hg at the last follow-up visit. Secondary outcomes were the occurrence of complications and mean IOP during the follow-up period.

Results: In all patients, the mean IOP reduced from 23.5 ± 3.0 mmHg before treatment to 15.7 ± 5.4 mmHg at 12 months (P < 0.05). Successful IOP control after a single procedure was 78.3% (79% and 78% in the 8 s and 10 s groups, respectively) at 12 months. Overall, the mean IOP reduction achieved in responding patients was 41% (standard deviation = 12%). Notwithstanding minor side effects such as transient pain, anterior chamber reaction, and refractive error changes, no major intraoperative or postoperative complications (severe hypotony or phthisis) were observed during the follow-up.

Conclusion: Our short-term results reveal that UCP is a simple, safe, and noninvasive procedure which enables to significantly reduce the IOP in patients with OAG. The study results in Indian eyes corroborate findings in earlier studies on Caucasian eyes.

Keywords: Cycloablation; glaucoma; ultrasound.

Conflict of interest statement

There are no conflicts of interest

Figures

Figure 1

High intensity focused ultrasound device components. (a) Treatment probe with six miniaturized piezoceramic transducers. (b) Coupling cone. (c) Ultrasound console. (d) Cross-section of the high intensity focused ultrasound device and coupling cone placed on the eyeball maintained in position by a suction ring. The ultrasound beam generated from the transducer focuses on a linear area (dotted line) within the ciliary body

Figure 2

Flow chart of the study

Figure 3

Graph showing intraocular pressure reduction (mean ± standard deviation in mm Hg) in all patients at baseline and each follow-up visit

Figure 4

Scattergram showing the preoperative visual acuity (x-axis) versus postoperative 12 months visual acuity (y-axis) in all