pkh-26 and Ocular-Hypertension

The damage to disk microcirculation in glaucoma and ocular hypertension is correlated with the damage to the neuronal tissue. However, it is not clear whether the primary damage is vascular or neurogenic. We have developed a new method which allows in vivo observation of the retinal capillary blood cell flow and the plasma flow, separately. The method was used to examine the blood cell flow in the optic disks of cats' eyes. The intraocular pressure was controlled by extra-fine intraocular canula at the anterior chamber. It was found that blood cell flow became stagnant in a few capillaries at the optic disk with an intraocular pressure of 30-45% of the systemic mean blood pressure. When an induced IOP increase to 45% of systemic mean blood pressure was sustained for 30 minutes, microcirculatory blood flow recovery was complete two hours later. When this pressure was sustained for 120 minutes, the recovery was incomplete two hours later. This work represents a new tool in the research of retinal and disk hemodynamics and microvascular pathologies. The results presented in this paper support the hypothesis that early ischemic microdamage might be the basis of the pathogenesis of the chronic glaucomas.

Topics: Animals; Blood Cells; Blood Flow Velocity; Blood Pressure; Capillaries; Cats; Fluorescein Angiography; Fluorescent Dyes; Fundus Oculi; Intraocular Pressure; Microcirculation; Ocular Hypertension; Optic Disk; Organic Chemicals; Retinal Artery