Rules of the IVFA

The Choriocapillaries

Choriocapillaries are fenestrated. As a result, dye diffuses readily through the choriocapillaries giving the characteristics choroidal blush.

The choroid can sometimes appear patchy because of different filling pressures of the short posterior ciliary arteries.

The Retinal Vessels

Retinal vessels do not have fenestrations. They form a tight blood - retinal barriers. Dye does not diffuse through the retinal vascular endothelium or the retinal pigmented epithelium in a healthy eye.

Neovascularization or disease states can compromise this retinal-blood barrier causing patterns of hyper or hypo-fluoresence on the flourescein angiogram.