The Effect of High dose Corticosteroid Therapy on the Optic Nerve Head Blood Flow in Experimental Traumatic Optic Neuropathy

ABSTRACT

The objective of this study was to establish the effect of high dose steroid therapy in traumatic optic neuropathy with Heidelberg Retina Flowmeter(HRF) to detect the changes of optic nerve head bleed flow. HRF permits the noninvasive assessment of the blood velocity, volume and flow(flux) in a sample volume of the nerve head. Such measurements were performed in two groups of experimental traumatic optic neuropathy rabbits. We experimentally damaged the optic nerves of ten white rabbits with a Hartman mosquito. The first group(n=5) was intravenously infected with 0.25mg/kg dexamethasone every six hours for a 48 hour period. The second group(n-5) was used as controls. Both groups were tested before operation, 1 week, 1 month, and 2 months later Experimental optic nerve damage created a significant decrease in optic nerve head blood flow 50.51%(p=0.001), with blood volume decreased by 46.02%(p=0.001) and blood velocity reduced by 43.12%(p=0.002) compared to the baseline value. After 2 months of high dose corticosteroid therapy, optic nerve head blood flow was increased by 76.90% (p=0.012), blood volume 77.53%(p=0.012)and blood velocity 47.21%(p=0.012) as compared to control group. The high dose corticosteroid therapy improved the optic nerve head blood flow as demonstrated in traumatic optic neuropathy. HRF may be used to assess the therapeutic responses in traumatic optic neuropathy under variable conditions.