Intraocular tissue plasminogen activator in a rabbit model of traumatic hyphema
G. R. Howard, J. Vukich, R. G. Fiscella, M. D. Farber and M. F. Goldberg
Department of Ophthalmology, UIC Eye Center, University of Illinois, Chicago 60612.
Tissue plasminogen activator was used to evaluate the clearance of
traumatic hyphema in a rabbit model. A neodymium-YAG laser was used to
disrupt iris vessels, creating a traumatic hyphema. Tissue plasminogen
activator (1800 IU/0.1 mL) was injected into the anterior chamber 24 hours
after creation of the hyphema. Two control groups (one receiving balanced
salt solution and one receiving no treatment) were used for comparison. A
multivariate analysis of covariance indicated that the greatest difference
in hyphema clearance between the groups occurred at days 3, 4, and 5. Five
days after tissue plasminogen activator treatment, the mean size of the
clot remaining in the anterior chamber was 27% of that of the original
hyphema. In control eyes, almost 60% of the original clot remained at day
5. Treatment of animals with tissue plasminogen activator doses of 5000 IU
and 10,000 IU produced a substantial increase in repeated bleeding episodes
in our rabbit model. We concluded that although the use of tissue
plasminogen activator in our rabbit model of traumatic hyphema
significantly improved clearance of blood from the anterior chamber, the
remaining clot was of such size that the clinical benefit was questionable.
