Expulsive choroidal hemorrhage in rabbits. A histopathologic study.

Expulsive hemorrhage is a catastrophic complication of intraocular surgery that can result in total loss of vision. Suprachoroidal effusion and hemorrhage may precede the development of expulsive hemorrhage; however, the relationship remains unclear. After sedation with intravenous pentobarbital sodium, 11 rabbits were given lactated Ringer's solution and heparin sodium intravenously. The right eyes were proptosed, and the central cornea, lens, and anterior vitreous were removed. After surgery, all 11 eyes (100%) developed choroidal effusion, choroidal hemorrhage, or expulsive hemorrhage. The rabbits were killed at various intervals after surgery so that the eyes could be enucleated and processed for light microscopy. Histologic examination revealed four sequential stages of expulsive hemorrhage as follows: (1) There was engorgement of the choriocapillaris. (2) Suprachoroidal effusion occurred mainly near the posterior pole. (3) As the effusion enlarged, stretching and tearing of choroidal vessels as well as tearing of the vessels and attachments at the base of the ciliary body occurred. (4) Massive extravasation of blood, primarily from the torn vessels at the ciliary body base, resulted in suprachoroidal hemorrhage and expulsion of blood through the surgical wound. This experimental model may provide new information relating to the cause and prevention of expulsive choroidal hemorrhage.