Intravitreal injection of dispase causes retinal hemorrhages in rabbit and human eyes.

PURPOSE

To check the effects of intravitreally injected dispase in the vitreo-retinal region.

METHODS

Dispase, 0.05 to 2.5 units dissolved in 100 microl of phosphate-buffered saline, was injected into the midvitreous of rabbits which were killed from 15 to 120 min afterwards. The enzyme was also injected into four human eyes of patients with orbital tumors 15 min before enucleation during orbital exenteration surgery. The eyes were examined in vivo as well as by light and electron microscopy.

RESULTS

Hemorrhages were detected by fundus observations and confirmed by microscopical analysis in nearly all rabbits and in half of the human eyes. The red blood cells were observed in the vitreous and retina. Breaches in the inner limiting membrane were visualized in human eyes and ruptures of small blood vessels in rabbit eyes. In spite of that, vitreous detachment was not verified. In fact, the cortical-vitreous collagen-fibril network was conspicuous on scanning electron micrographs.

CONCLUSIONS

Retinal hemorrhages were evident as early as 11 min after injection. It is suggested that this enzyme degraded selectively basement membrane components without affecting other proteins involved in the vitreous-retinal junction.