The human fovea.

While the fovea occupies only about 0.1% of the total retinal surface area, it is arguably the most important region of the human retina. The human fovea is characterized by unique anatomic specializations relative to the rest of the retina, which include an absence of inner retinal layers and the accompanying vasculature, an increased density of cone photoreceptors, a near-absence of rod photoreceptors, and a unique "private-line" midget ganglion cell circuitry. These anatomic specializations are responsible for our high-acuity vision. Unfortunately, as a result, even minor disruptions to foveal structure can have dire consequences for visual function. There is a growing number of noninvasive imaging modalities that enable direct visualization of foveal structure in humans, some with the ability to resolve individual cone photoreceptor cells. Through the lens of these in vivo imaging advances, we provide a general overview of the basic anatomic specializations of the human fovea, define the normal variation in foveal anatomy, and describe the foveal manifestations of some well-studied developmental and degenerative retinal disorders (e.g., albinism, premature birth, and achromatopsia).