Chronic ocular hypertension in rabbits induced by limbal buckling

To establish a rabbit model of chronic ocular hypertension (OHT) by limbal buckling.

Eighteen New Zealand White rabbits were involved and divided into three groups. A latex encircling band of 20, 25 or 35 mm was implanted behind the limbus in the right eye of each animal. The intraocular pressure (IOP) was monitored for 8 weeks, after which optic nerve damage was evaluated by fundus photography, optical coherence tomography (OCT) retrograde labelling and histology. Meanwhile, the anterior chamber angle (ACA) was examined by OCT and gonioscopy.

OHT was induced in all animals after surgery. The IOP peaked at 38.0±3.7, 32.0±3.9 and 24.1±6.5 mm Hg in groups 1, 2 and 3, respectively, and remained elevated for 22, 25 and 39 days on average, respectively. The elevated IOPs showed good consistency within 2 weeks, although the durations of high IOP varied moderately. The area ratio between the optic cup and disc (cup to disc area) was increased in 73% of the treated eyes, and the average changes were 0.10±0.13, 0.11±0.08 and 0.09±0.02 in groups 1, 2 and 3, respectively. The depth of the optic cup was also increased in the treated eyes, and the density of the retinal ganglion cells was reduced. Additionally, the ACA showed a dynamic change with IOP after the latter was reduced by paracentesis.

Limbal buckling provides an effective method of producing chronic OHT and glaucomatous optic neuropathy in rabbits.