Certified Ophthalmic Technician (COT) Practice Test 2025 - Free COT Practice Questions and Study Guide

The arterial phase of fluorescein angiography is the stage where fluorescein dye is visualized primarily in the arteries and in the choroid of the eye. During this phase, the dye is injected into the bloodstream and begins to circulate. As a result, the arteries fill with the fluorescein dye, allowing for visualization of the vascular structures and blood flow in the retina and choroidal circulation.

This phase typically occurs within the first few seconds after the dye injection, and it is crucial for evaluating conditions affecting the arterial blood supply to the eye. Analyzing this phase helps detect abnormalities such as arterial occlusions or changes in the arterial architecture.

The other phases of angiography, such as the early venous phase and later phases, introduce the visual representation of the venous system and any subsequent changes that occur in both blood circulation and the retinal structures, which is not the focus during the arterial phase itself. The intermediate and late phases would present additional information and gradual filling of the veins, which is irrelevant when specifically discussing the dye’s presence only in the arteries and choroid. Thus, identifying the arterial phase is essential for understanding the vascular dynamics during the initial moments of fluorescein angiography.