Retinochoroidal changes after severe brain impact injury in rabbits.

OBJECTIVE

To investigate retinochoroidal changes and establish eye damage model after brain impact injury.

METHODS

An eye damage model after brain impact injury was established by striking the frontoparietal zone in rabbits with BIM-II bioimpact machine. Seventeen rabbits were killed at 4 different intervals after injury. The pathological characteristics of the retinal and choroid damages were observed.

RESULTS

All the rabbits had severe brain injury with subarachnoid hemorrhage and brain contusion. The eye damage occurred in all of the 17 rabbits. Hemorrhage in optic nerve sheaths was observed and retinal edema and bleeding was discovered with ophthalmoscope. Histopathologic study displayed subarachnoid hemorrhage in the retrobulbar portion of the retinal nerve, general choroid blood vessel dilatation, retinal nerve fibre swelling within 6 hours after injury, and flat retinal detachment with subretinal proteinoid exudation, and degeneration and disappearance of the outer segment of the optic cell over 6 hours after injury.

CONCLUSIONS

The pathological characteristic of the eye damage at early stage following brain impact injury is local circulation disturbance. At late stage, it features in retinal detachment, and optic cellular degeneration and necrosis.