Exploring safety, efficacy of high-intensity focused ultrasound in glaucoma
High-intensity focused ultrasound cyclocoagulation is safe and effective in most refractory glaucomatous eyes. Complete success was achieved in 80% (24/30) of treated eyes that had undergone the maximum of three procedures.
Noninvasive glaucoma procedures (NIGPS) represent a new dawn in the management of glaucoma, as they try to fill the gap between the shortcoming of glaucoma surgeries and antiglaucoma medications.1
High-intensity focused ultrasound (HIFU) cyclocoagulation is a NIGPS that was introduced in the 1980s by Coleman et al. to selectively destroy ciliary body tissue and reduce aqueous humour production.2-4
Recently, the development of a new circular cyclocoagulation device, which uses miniaturised transducers to produce HIFU (EyeOP1 EyeTechCare, Rillieux-la-Pape, France), has renewed interest in the technique (see Figure 1).5,6 The procedure can also be defined as ultrasound ciliary plasty (UCP).
Parameters used are: 21 MHz operating frequency; six activated sectors; 2 to 3 W acoustic power; 8 seconds of the HIFU delivery time for each sector; and three different probe sizes (11-, 12- or 13-mm ring diameters) selected for each eye using preoperative biometric data based on AS-OCT image.7
Clinical trials in humans have shown that the device allowed a significant and predictable IOP reduction with a good local tolerance after one UCP treatment.5-8
In this study we aimed to evaluate success rate, long-term effectiveness and safety of multiple UCPs (up to three times per eye) in patients who experienced a lack of efficacy or incomplete success with prior glaucoma therapies.
Methods
Thirty eyes of 30 patients with medically uncontrolled primary and secondary glaucoma under maximal tolerated medical therapy were enrolled to undergo UCP treatment with the EyeOP1 device.
We evaluated all patients before treatment and at 1, 4, 10 days and each month until 1 year after the last treatment. The treatment was repeated after 4 months if the IOP was > 21 mm Hg without major complications.
Complete success was defined as a final IOP> 5 mm Hg and ≤ 21 mm Hg without hypotensive medications adjunction and without major or vision-threatening complications. A maximum of three procedures were performed.
Student’s t-test was used to compare means and percentages and the statistical significance was set at p < 0.01.
Results
The mean preoperative IOP was 34.4 ± 9.6 mm Hg. Four months after the first UCP treatment, the overall IOP reduction was 27.9%. Fifteen of the treated eyes did not achieve the complete success and a second treatment was performed.
Four months after the second UCP procedure took place, IOP declined by 21.9 % from preoperative values and by 34.6% from baseline. Complete success was not achieved in nine of the retreated eyes and, therefore, a third treatment was performed.
Four months after the third UCP treatment, the overall IOP reduction was 36.5% and 52.2% from baseline. At 12 months, complete success was achieved in 80% (24/30) of treated eyes that had undergone the maximum of three procedures, and there was a significant reduction of hypotensive medications.
No major complications occurred during and after any of the procedures.
Conclusions
Circular cyclocoagulation with HIFU is safe and effective. Compared with lasers, the selective ablation of ciliary bodies in the procedure and the controlled energy absorption, unrelated to ciliary bodies’ pigmentation, reduce both the impact on adjacent tissues and the hypotony risk (see Figure 2).
The results after the first treatment are comparable to those reported in previous trials.4-7 In conclusion, these data demonstrated a possible step-by-step successful approach in most refractory glaucomatous eyes, with the UCP procedure demonstrating a good safety profile, despite multiple administrations.
Some final take-home messages are:
· This procedure is non-invasive (the eye remains closed) and repeatable with very low postoperative side effects;
· UCP is selective for refractory glaucomas and reduces the risk of postoperative hypotony compared with diode laser procedure;
· It is a relatively pain-free procedure;
· UCP can be performed even in eyes with residual visual acuity.
References
1.Abdelrahman AM. Noninvasive glaucoma procedures: current options and future innovations. Middle East Afr J Ophthalmol. 2015;22:2-9.
2. Coleman DJ, Lizzi FL, Driller J, et al. Therapeutic ultrasound in the treatment of glaucoma. I. Experimental model. Ophthalmology. 1985;92:339-346.
3. Coleman DJ, Lizzi F, Driller J, et al. Therapeutic ultrasound in the treatment 185 of glaucoma, II: clinical applications. Ophthalmology. 1985;92:347-352.
4. Denis P, Aptel F, Rouland J-F, et al. Cyclocoagulation of the ciliary bodies by High-Intensity Focused Ultrasound: a 12-month multicenter study. Invest Ophthalmol Vis Sci. 2015;56:1089-1096.
5. Aptel F, Charrel T, Palazzi X, et al. Histologic effects of a new device for high-intensity focused ultrasound cyclocoagulation. Invest Ophthalmol Vis Sci. 2010;51:5092-5098.
6. Charrel T, Aptel F, Birer A, et al. Development of a miniaturized HIFU device for glaucoma treatment with conformal coagulation of the ciliary bodies. Ultrasound Med Biol. 2011;37:742-754.
7. Aptel F, Charrel T, Lafon C, et al. Miniaturized high-intensity focused ultrasound device in patients with glaucoma: a clinical pilot study. Invest Ophthalmol Vis Sci. 2011;52:8747-8753.
8. Aptel F. et al. Multicenter clinical trial of high-intensity focused ultrasound treatment in glaucoma patients without previous filtering surgery. Acta Ophthalmol. 2015;94:e268-e277.
9. Mastropasqua R. et al. Uveo-scleral outflow pathways after ultrasonic cyclocoagulation in refractory glaucoma: an anterior segment optical coherence tomography and in vivo confocal study. Br J Opthalmol. 2016;0:1-8.
Dr Alessandra De Gregorio, MD
Dr De Gregorio is a consultant in the Department of Ophthalmology, S. Bassiano Hospital, Bassano del Grappa, Italy. Dr De Gregorio states that she has no financial interests in the products mentioned.
Dr Antonio Toso, MD
Dr Toso is head of the Vitreoretinal Surgery Unit, Department of Ophthalmology, S. Bassiano Hospital, Bassano del Grappa, Italy. Dr Toso states that he has no financial interests in the products mentioned.
Dr Simonetta Morselli, MD
Dr Morselli is head of the Department of Ophthalmology, S. Bassiano Hospital, Bassano del Grappa, Italy. Dr Morselli states that she has no financial interests in the products mentioned.
E: simonetta.morselli@gmail.com
