Preliminary study on the treatment of acute angle closure glaucoma with high intensity focused ultrasound cycloplasty

High-intensity focused ultrasound cycloplasty (UCP) can effectively reduce intraocular pressure in glaucoma patients. This work aimed to analyze the efficacy, safety, and mechanism of UCP in treating acute angle-closure glaucoma. We collected and retrospectively analyzed the preoperative and postoperative clinical data of 16 cases (16 eyes) with acute angle-closure glaucoma, including the number of sectors activated, intraocular pressure (IOP), central anterior chamber depth (ACD), lens zonule length (LZL), ciliary muscle thickness (CMT), and trabecular-ciliary process angle (TCA). Of the 16 eyes, one received a single UCP procedure with 8 sectors, and the others with 10 sectors. The mean IOP at follow-up time points after UCP was significantly lower than before UCP. The mean ACD at follow-up time points after UCP was significantly higher than before UCP. The mean LZL in the superior, inferior, nasal, and temporal quadrants on postoperative day 1, week 1, and month 1 was significantly shorter than that before UCP. The mean CMT in the superior, inferior, and nasal quadrants on postoperative day 1 and in the superior and inferior quadrants on postoperative week 1 were significantly larger than those before UCP. The mean TCA in the temporal quadrant on postoperative month 3 was significantly smaller than that before UCP. In conclusion, UCP is safe and effective in treating acute angle-closure glaucoma. The special mechanism of lowering IOP after UCP may be attributed to the increased depth of the central anterior chamber and the reopening of some non-adhesive closed angles.