Purchase this article with an account.
I. V. Zapuskalov, O. B. Kochmala, I. A. Dashko, O. I. Krivosheina, J. I. Khoroshikh; The Direction and Speed of the Fluid Flow in Outer Retinal Layers. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5022.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The interstitial fluid, flowing from choriocapillaries, passes through the pigment epithelium and the outer retinal layers, and is absorbed by the retinal vessels.
Poiseuille’s law, the fluorescent angiography results.
It is known from the literature that the diameter of retina capillaries ranges within 5-10 µm, while the diameter of choriocapillaries is about 20-30 µm (like in vessels of the ciliary body). As both these types of capillaries are terminal branches of the orbital artery, according to Poiseuille’s law, the transmural pressure in choriocapillaries is higher than that in retinal capillaries. Taking into account that they belong to the same hydraulic system that lies within the fibrous capsule of the eye, the fluid outflows from the choriocapillaries due to pressure gradient and then is absorbed in retinal capillaries. This theoretical assumption is confirmed by the fluorescent angiography results. Normally, we observe the fluorescein flowing out only from choriocapillaries, while the retinal vessels show no extravasation.
The absence of the fluorescein outflow from retinal vessels is not attributed to the existence of the blood-ocular barrier; it does not go out because the transmural hydrostatic pressure in retinal capillaries is lower than the osmotic pressure of plasma and it explains the one-direction flow of fluid from tissue to exchange retinal vessels.
This PDF is available to Subscribers Only