Diagnosis: Imaging Dyes (IVFA and ICG)

Mark H. Nelson

Oct 29, 2023 — 1 min read

If your doctor finds leakage, or exudation, under your retina and the diagnosis of Exudative Age-Related Macular Degeneration (ARMD) is made, he/she may inject an imaging dye into your vein and take photos of the macula/retina. This test is critical to determine what type of Exudative ARMD you have - there is no 'one size fits all'. There are many phenotypes, or different ways in which the disease presents. This is important because different phenotypes respond to anti-VEGF drugs differently (more later). OCT, OCT Angiography (OCTA), flourescein angiography (IVFA), and indocyanine green (ICG) are all used to best diagnose, treat and follow these diseases.

The image above shows how neovascularization can be appreciated on each modality. Below, a cross section of the retina shows neovascularization on OCT. The photo on the top right shows how this neovascularization is appreciated on OCTA, the middle photo by ICG and the top left photo on IVFA.

Exudative ARMD - Treatment Principles

Prior to the introduction of anti-VEGF drugs in 2006, the prognosis for patients with Exudative ARMD was not good. A small number of patients who were treated with thermal laser (prior to 2000) or PDT laser (after 2000) were lucky to have vision stabilized - better vision was not obtained.

What are the causes of vision loss?

Let's take an intermission prior to discussing Exudative ARMD. Obviously the most important concept of macular disease is vision loss. We all know that good vision was the norm in youth. We all know it becomes a challenge as we age. Here are the four reasons for vision loss: 1.

Diagnosis: Dry (Nonexudative ) versus Wet (Exudative) ARMD

Before delving into the finer details, let's look at couple of simple things. Dry ARMD is not the same as dry eyes, i.e. the tearing of dry eyes is in the front of the eye and has nothing to do with 'leakage' in the back part of the eye.

Diagnosis: OCT part 2 and OCT Angiography (OCTA)

When we look at an OCT, we look at a cross section of the retina as shown in the left photo. The right photo is the cross section of the macula at the level of the bright green line shown on the left. (1) denotes a relatively normal retina. (2)

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Exudative ARMD - Treatment Principles

What are the causes of vision loss?

Diagnosis: Dry (Nonexudative ) versus Wet (Exudative) ARMD

Diagnosis: OCT part 2 and OCT Angiography (OCTA)