The fovea is approximately _____________ mm in diameter.

• A. 1.0 mm
• B. 1.5 mm
• C. 2.0 mm
• D. 2.5 mm

Answer: (B)

The fovea centralis spans about 1.5 mm in diameter. This small, cone-rich pit sits at the center of the macula and is characterized by thinning of the inner retinal layers to minimize light scattering, which yields the sharpest central vision. This size is a standard reference in ocular anatomy and aligns with imaging and histology data showing the fovea as a roughly 1.5 mm-wide area of peak acuity. If the diameter were as small as 1.0 mm, the central acuity region would be even more restricted; if it were 2.0–2.5 mm, the foveal area would be larger than what is consistently observed histologically and on imaging.