Chronic Hypotony Model in the Rabbit

ABSTRACT

Chronic hypotony is an importnat cause of functional failure after proliferative vitreoretinopathy(PVR) surgery even if the retina is successfully reattached. The purpose of this study was to create a relevant model of chronic hypotony in the rabbit. Eighteen pigmented rabbits weighing 3~4kg were used in this experiment. Pars plana lensectomy was performed on fourteen eyes of fourteen rabbits with a fragmatome and a vitreous cutter. At the end of surgery, 0.2ml of phosphate-buffered saline(PBS) containing 100,000 cells of cultured rabbit dermal fibroblasts was injected over the epiciliary area. As a control, pars plana lensectomy alone was done on four eyes of four rabbits. The intraocular pressure(IOP) was measured on days 7, 14, 21, 28. All fourteen eyes following lensectomy and fibroblast injection had an IOP less than 5mmHg on each follow-up and a mean of 2.5+/-0.6mmHg (mean+/-S.D.) on day 28. Four control eyes with lensectomy alone had an IOP of 7.5+/-2.1mmHg(mean+/-S.D.) on day 28 (P<0.05). On gross examination, the development of fibrous translucent epiciliary membrane was found on day 28. Microscopic examination of eyes obtained on day 28 showed changes in the ciliary epithelium that included an absence or atrophy of the non-pigmented ciliary epithelium, an atrophy and cystic vacuolization of the pigmented ciliary epitheliu, and the interstitial edema of the ciliary body stroma. In conclusion, a model of chronic hypotony with epiciliary membrane using cultured fibroblasts was created in the rabbit. This model may be useful to help elucidate the pathophysiology of chronic hypotony and to investigate potential treatments.