Table 2.

Difference between FI and OCT.

Modality	Image Formation	RF #	Features of Interest	Limitations
FI	Colour photograph of the retinal surface.	7–20	Blood vessels, lesions, exudates, hemorrhages.	Dilation of pupils is often needed.
OCT	Near-infrared light penetrates the retina.	4	The internal retinal structure is shown in cross-section, including changes in the nerve fiber layer.	Susceptible to media opacities, does not visualize blood.

^#: Resolution factor; FI: fundus imaging; OCT: optical coherence tomography.