What is the width of the fovea in degrees?

What is the width of the fovea in degrees?

• A. Two degrees
• B. Five degrees
• C. Eight degrees
• D. One degree

Answer: (B)

Understanding how retinal size translates to the visual field helps answer this. The fovea is a tiny pit in the retina with a diameter of about 1.5 mm. In typical eyes, about 0.3 mm on the retina corresponds to 1 degree of visual angle, so 1.5 mm translates to roughly 5 degrees. That’s why the fovea is said to span about five degrees of the visual field: it’s a small central region that provides the sharpest vision. The other options are too small or too large given the actual physical size of the fovea on the retina.

Understanding how retinal size translates to the visual field helps answer this. The fovea is a tiny pit in the retina with a diameter of about 1.5 mm. In typical eyes, about 0.3 mm on the retina corresponds to 1 degree of visual angle, so 1.5 mm translates to roughly 5 degrees. That’s why the fovea is said to span about five degrees of the visual field: it’s a small central region that provides the sharpest vision. The other options are too small or too large given the actual physical size of the fovea on the retina.