Dictionary.net

area consisting of a small depression in the retina containing cones and where vision is most acute

area consisting of a small depression in the retina containing cones and where vision is most acute

An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)

Pit in middle of macula lutea.