• Course Information
  • Introduction
    • Basics of Neurohistology
      30 min
  • Cerebellum
  • Cerebrum
  • Spinal Cord
  • Inner ear
  • Eye & Eyelid
  • Final Exams



Eye layers

Anatomy of the eye — OpenStax — CC BY-SA 4.0

The eye consists of both an optical system that allows the change of focus and controls the amount of light coming in and a sensory apparatus that receives concentrated visual information and transduces it to an electrical impulse that is carried by the optic nerve.

Our histological slides are of a meridional plane, which is perpendicular to the equatorial plane.

Layers of the eye

The wall of the eye can be divided into three layers:

  1. External (fibrous)
  2. Middle (vascular)
  3. Inner (retinal)

External (fibrous) layer

Also called the corneoscleral layer, since it consists of the cornea (transparent, avascular outermost layer at the front of the eye), and the sclera (the “white” of the eye — highly vascular).

Middle (vascular) layer

Also called the uvea. Consists of:

  1. Iris with the pupil in the middle — The aperture through which light goes in.
  2. Ciliary body – Secretes aqueous humor and produces zonula fibers to attach the lens. Similar to the choroid plexus and stria vascularis.
  3. Choroid – A dark vascular sheet.

Inner (retinal) layer

Consists of the retina which at large, is the sensory apparatus containing photo-receptors.

Histological slide of the eye — University of Michigan — CC NP-SA 3.0

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