Which cones are NOT located within the foveola?

Which cones are NOT located within the foveola?

• A. Red cones
• B. Blue cones
• C. Green cones
• D. Yellow cones

Answer: (B)

In the foveola, you have an extremely dense packing of cone photoreceptors that supports the sharp, color-rich central vision. The cones present there are mainly the long- and medium-wavelength types, which correspond to red and green pigments. Short-wavelength (blue) cones are largely absent from the foveolar center and are found more in the surrounding retina (parafovea). Because blue cones aren’t located in the foveola, the correct choice is the one that refers to blue cones. Note that yellow cones aren’t a separate cone type in human retina—the three types are red (L), green (M), and blue (S); red and green cones are present in the foveola, while blue cones are not.

In the foveola, you have an extremely dense packing of cone photoreceptors that supports the sharp, color-rich central vision. The cones present there are mainly the long- and medium-wavelength types, which correspond to red and green pigments. Short-wavelength (blue) cones are largely absent from the foveolar center and are found more in the surrounding retina (parafovea). Because blue cones aren’t located in the foveola, the correct choice is the one that refers to blue cones. Note that yellow cones aren’t a separate cone type in human retina—the three types are red (L), green (M), and blue (S); red and green cones are present in the foveola, while blue cones are not.