What is a fluorescein angiogram primarily used to view?

A fluorescein angiogram is primarily utilized to visualize the retinal blood vessels and assess conditions affecting the retina, such as blockages or areas of leakage. During this procedure, a fluorescent dye (fluorescein) is injected into a vein, allowing for detailed imaging of the blood flow in the retina. This enables healthcare professionals to identify abnormalities like diabetic retinopathy or macular degeneration, which can manifest as blockages or other vascular irregularities in the ocular fundus.

The other options, while related to eye health, do not pertain to the primary function of fluorescein angiography. Counting epithelial cells is a different diagnostic process typically associated with cytological analysis. Measuring the eye's contrast sensitivity focuses on the visual function rather than blood vessel imaging. Estimating the cornea's ability to withstand stress is related to corneal assessments and surgical considerations, rather than the vascular observations made during a fluorescein angiogram.