The Normal Eye

The Uveal tract is the middle layer of the eye

The uvea (Latin: uva, grape), also called the uveal layer, uveal coat, or uveal tract, is the pigmented middle layer of the three concentric layers that make up an eye.

The prime functions of the uveal tract as a unit are:

  • Nutrition and gas exchange
  • Light absorption (analogous to the black paint inside a camera), and also absorbs outside light transmitted through the sclera, which is by no means opaque.
  • In addition, some uveal regions have special functions of great importance, particularly
    • Secretion of the aqueous humour (fluid of the front part of the eye) by the ciliary processes,
    • Control of accommodation (focus for near vision) by the ciliary body
    • Optimisation of retinal illumination by the iris control over the pupil.