THE EFFECT OF IMMEDIATE DECOMPRESSION ON THE OPTIC-NERVE IN RETROBULBAR HEMATOMA

We produced retrobulbar hematoma in both orbits of 10 pigs in order to assess the effects of blood elements and pressure created by the hema toma on the optic nerves. Ten other pigs were used as a control group. Following decompression in the right orbits, ocular movements, fundi, and intraocular pressure were evaluated for 6 weeks. At the end of th e 6th week the optic nerves of 20 pigs were dissected bilaterally for measurements of ATP-ase activity and ultrastructural examination. The results of the ultrastructural examination of the optic nerves of the control group were normal. Optic nerves with decompressed retrobulbar hematoma showed minimal degeneration, whereas the nerves subjected to retrobulbar hematoma with no decompression showed significant degenera tive changes. For all groups ATP-ase activities were measured and eval uated. Na+, K+ ATP-ase activities decreased, while Ca++, Mg++ ATP-ase activities increased with the extent of degeneration. Optic nerve dama ge can develop after trauma. Decompression procedures are not among th e causes of optic nerve degeneration but retrobulbar hematoma can resu lt in optic neuropathy caused by the compression from the hematoma and the direct effect of blood waste products on the optic nerve.