Transvitreal chorioretinal biopsy in the rabbit.

Transvitreal chorioretinal biopsy was performed in nine Dutch rabbits by introducing a biopsy instrument through a small eye wall incision, passing the instrument across the eye through the vitreous to the biopsy site, and by trephinating and removing from the eye a 1.6-mm diameter specimen of the posterior eye wall. Biopsy was carried out under stereotaxic control by using a micromanipulator especially designed for ophthalmic surgery. Hemostasis was achieved by circumferential mechanical pressure around the biopsy site. The eye wall defect was sealed by a preplaced explant and repaired by fibrovascular ingrowth from the surrounding choroid and episclera. The normal histologic features of the biopsy specimen were preserved, except for separation of the neurosensory retina from the pigmented epithelium. Complications of the procedure included hemorrhage from the incision site, transvitreal strand formation, and lens abrasion. In no instance, however, did these complications result in significant opacification of the optical media. The biopsy technique has potential use as a clinical procedure in the diagnosis of choroidal tumors and other selected disorders of the choroid and retina and as a technique in investigational animal studies.