Macula lutea ("yellow macula")

the center of vision, characterized by yellow pigment permeating the retinal layers. Size: approximately 3-5 mm in diameter (less than the size of the letter "o" in this sentence). Contains the fovea in its center, which is responsible for the highest visual acuity. Contains no blood vessels except in its periphery, and receives nourishment from the choroid.
(See Anatomy of the Eye" on the MD Support web site.)