Purchase this article with an account.
Aurelie Begle, Florent Aptel, Cyril Lafon, Jean-Yves Chapelon, Fabrice Romano; Aqueous production reduction and aqueous outflow increase in rabbit eyes after ultrasonic cyclocoagulation. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1860.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To study the mechanisms of action of an ultrasonic cyclocoagulation treatment on the reduction of intraocular pressure in rabbit eyes
Nine eyes of 9 rabbits were insonified with a ring-shaped probe containing 6 miniaturized high-intensity focused ultrasound transducers operating at 21 MHz. The acoustic power was set at 2,45 W, and the exposure duration at 6 sec per transducer. The rabbits were followed for up to 22 days, with regular IOP measurement and ophthalmic examinations (day 0 before treatment, 5, 10 and 21 days after) and then sacrificed to perform histological examinations of the treated eyes (light microscopy, scanning electron microcopy, scanning electronic microcopy after intravascular injection of methacrylate resin)
IOP was reduced from a mean preoperative value of 10.4 ± 1.5 mmHg before treatment to a mean postoperative value of 6.8 ± 1.4 mmHg, 7.2 ± 2mmHg and 7.1 ± 1.7mmHg respectively at 5, 10 and 22 days. No macroscopic abnormalities were found. In the affected regions, the distal and intermediate parts of the ciliary processes showed acute inflammatory and necrotic changes ranging from stromal edema and vascular congestion. The bi-layered epithelium was degenerated or necrotic and sloughed off in the distal parts of the most affected areas, resulting in decrease of aqueous humor production. Histological examinations performed several weeks after the treatment showed involution of the ciliary processes, with short or absent ciliary processes covered by a non bi-layered epithelium and composed of dysmorphic and probably nonfunctional cells. Light microscopy and scanning electron microscopy of vascular corrosion cast performed after intravascular injection of methacrylate resin shows focal interruption of the ciliary body microvasculature with dimensions comparable to those of lesions observed with light or scanning electron microscopy. In most animals treated, a fluid space could be seen between the sclera and the ciliary body and between the sclera and the choroid adjacent to treated areas. This aspect therefore likely corresponds to an area where the opening of the space should lead to an increase of the aqueous outflow via the uveoscleral pathway.
Ultrasonic cyclocoagulation using high-intensity focused ultrasound results in dual effect on the dynamics of aqueous humor contributing both to lower IOP.
This PDF is available to Subscribers Only