Certified Ophthalmic Assistant Practice Exam

Which imaging technique does not output a color-coded map?

1. Indocyanine green chorioangiography (ICG)

2. Fluorescein angiography (FA)

3. Confocal scanning laser ophthalmoscopy (cSLO)

4. Optical Coherence Tomography (OCT)

The correct answer is: Indocyanine green chorioangiography (ICG)

Indocyanine green chorioangiography (ICG) is the imaging technique that does not output a color-coded map. This technique uses near-infrared light to visualize the movement of a dye injected into the bloodstream. This imaging technique is primarily used in ophthalmology to examine the choroidal circulation in the eye. A color-coded map is not outputted because the dye is not specifically targeted to any specific structures, therefore the images produced do not have distinct color coding. The other imaging techniques, such as Fluorescein angiography (FA), Confocal scanning laser ophthalmoscopy (cSLO), and Optical Coherence Tomography (OCT) all produce color-coded maps. FA uses a fluorescent dye to visualize the vasculature in the eye and can produce color-coded images. cSLO uses a laser to produce high resolution, 3D images of the eye which can also be color-coded. OCT uses infrared light to produce highly detailed cross-sectional images of the eye, which can also be color-coded to better visualize structures. Therefore, A is the only option that does not output a color-coded map.