The postnatal development of blood vessels in the optic nerve of normotensive and hypertensive rats.

The blood vessels in the optic nerve of normotensive and hypertensive rats have been examined at 2, 4, 8 and 12 weeks of age. The pattern of development was found to be different in the two strains, with the number of blood vessels in the hypertensive rat optic nerve being lower at 2 weeks, but greater at 12 weeks than the normotensive rat. There appeared to be no correlation between vascularity and either myelination or changes in the fibre diameter spectrum at the ages studied. It is concluded that while the cause of the increased vascularity of the optic nerve in hypertensive rats is not known, it appears to be without effect in the structural development of the optic nerve.