What is the role of fluorescein angiography in the workup of central retinal vein occlusion (CRVO)?

Updated: Apr 18, 2019
  • Author: Lakshmana M Kooragayala, MD; Chief Editor: Douglas R Lazzaro, MD, FAAO, FACS  more...
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Answer

Fluorescein angiography is the most useful test for the evaluation of retinal capillary nonperfusion, posterior segment neovascularization, and macular edema. [2] Note the images below.

Fluorescein angiogram of a patient with nonischemi Fluorescein angiogram of a patient with nonischemic central retinal vein occlusion, showing staining of dilated tortuous veins with leakage into macula in a cystoid pattern.
Fluorescein angiogram of the same patient as in pr Fluorescein angiogram of the same patient as in previous image, showing perifoveal capillary leakage in a cystoid pattern in late phases of angiogram.
Late phase of fluorescein angiograph of the same p Late phase of fluorescein angiograph of the same patient as in previous image, showing cystoid pattern of leakage from perifoveal dilated leaking capillary network.

Fluorescein angiography is one of the tests used in the classification of CRVO. Areas of capillary nonperfusion are visualized as hypofluorescence, but hemorrhages can block fluorescence and give a similar picture. Therefore, in the early stages of the disease process, due to extensive hemorrhages, fluorescein angiography gives little information regarding the perfusion status of the retina. Once the hemorrhages clear, areas of capillary nonperfusion can be detected as hypofluorescence in the fluorescein angiography. Wide-angled fluorescein angiography is useful tool to detect areas of retinal perfusion and non-perfusion in mid and peripheral retina in early stages of disease. [21]

Various studies have reported different criteria for defining ischemic CRVO versus nonischemic CRVO based on the extent of capillary nonperfusion of the retina. The amount of retinal nonperfusion ranges from 10-30 disc areas.

In addition, fluorescein angiography may show delayed arteriovenous transit, staining along the retinal veins, microaneurysms, arteriovenous collaterals, NVD, NVE, and dilated optic nerve head capillaries.

In a nonischemic central retinal vein obstruction, angiography may show minimal or absent retinal capillary nonperfusion, staining along the retinal veins, microaneurysms, and dilated optic nerve head capillaries. Resolved CRVO may be completely normal.

Macular edema may be detected as leakage from perifoveal capillaries (depicted in the image below), leakage from microaneurysms, or diffuse leakage on fluorescein angiography. If extensive edema is present, fluorescein angiography may show pooling of dye in large cystoid spaces. In addition, capillary nonperfusion around the fovea may indicate macular ischemia. If macular edema persists, pigmentary changes become evident.

Arteriovenous phase of fluorescein angiograph show Arteriovenous phase of fluorescein angiograph showing perifoveal capillary leakage in a patient with nonischemic central retinal vein occlusion.

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