Abstract
Purpose :
To describe a novel and relatively simple method for inducing a highly consistent, modest, and repeatable elevation in intraocular pressure (IOP) for rabbits.
Methods :
A total of 2 male New Zealand White rabbits were sacrificed to obtain vitreous tissue. For vitreous aspiration, a 21-gauge needle was introduced into the vitreous of the eye through the superotemporal sclera 1 mm behind the limbus. A total of 6 male New Zealand White rabbits weighting 2.1 to 2.5 kg were used for the vitreous allograft procedure. IOP was elevated unilaterally by injection of vitreous (0.7-0.8 ml) into the anterior chamber to occlude aqueous outflow. To minimize the egress of vitreous and aqueous fluid from the injection track, double-plane tunneled scleral injection method with 26-gauge needle was applied to approach anterior chamber. The fellow eye received an equivalent saline injection as internal control. IOP measurements were performed with the TonoVet (Helsinki, Finland) tonometer with a rabbit calibration mode. The rabbit eyes were examined under a microscope to assess any possible abnormalities in the conjunctiva, cornea, and anterior chamber.
Results :
The mean baseline IOP was 10.0±0.9 mmHg and 10.2±1.3 mmHg in vitreous allograft eyes and control eyes, respectively. The mean IOP was significantly increased to 17.2±1.1 mmHg at 5 minutes after the injection of vitreous (Wilcoxon singed rank test, P = 0.028). However, in the control eyes, the IOP did not significantly increased from baseline (10.5±1.0 mmHg, P = 0.520). A single vitreous injection raised mean IOP by 32.7% (13.6±1.9 mmHg, P = 0.027), for 4 weeks, though they were not tracked to full recovery. IOP in the saline-injected eye was constant. The rabbits’ eyes did not show any apparent complications in conjunctiva, cornea, and anterior chamber for 4 weeks.
Conclusions :
These data support a novel and flexible model of modest ocular hypertension in rabbits. The maximal duration of IOP elevation, the relationship between injection volume and the magnitude of IOP elevation should be further characterized in future studies.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.