Neuroanatomy, Retina

Excerpt

The retina is the innermost layer in the eye that is responsible for the visual processing that turns light energy from photons into three-dimensional images. Located in the posterior portion of the eyeball, the retina is the only extension of the brain that can be viewed from the outside world and gives ophthalmologists a rare window into real-time pathology affecting the retina. Development of the retina is a long and complex process that begins during the fourth week of embryogenesis and continues into the first year of life. This long and complex embryonic development makes the retina vulnerable to genetic and environmental insults that can negatively affect retinal development. Retinal tissue develops to become the most metabolically expensive tissue in the human body, consuming oxygen more rapidly than any other tissue. The retina is fed oxygen from a unique dual blood supply that divides the retina into outer and inner layers for more efficient oxygenation. The retina itself consists of six different cell lines divided into ten different layers, each playing a specific role in creating and transmitting vision. The different cell types perform a particular role and form functional circuits that specialize in detecting specific variations and movements of light.