Anatomy and Function of the Eye

Introduction

• The eye is an organ responsible for vision.
• Vision is possible due to photoreceptors that detect light.
• Eyes are protected by bony orbits that deflect impacts.

Anatomical Layers of the Eye

• Fibrous Layer

  • Composed of the cornea and sclera.
  • Provides shape and structure to the eyeball.
  • Cornea: Bends light to focus it inside the eye.
  • Sclera: Serves as an attachment site for extraocular muscles.

• Extraocular Muscles

  • Located at the sides of the eyeball.
  • Responsible for all eye movements.

• Vascular Layer

  • Contains the ciliary body, choroid, and iris.
  • Choroid: Houses blood vessels that supply the retina.
  • Iris: Controls the pupil size, acting like an aperture via smooth muscle fibers.
  • Ciliary Body:
    • Composed of muscles and processes.
    • Attached to the lens, altering its shape to change focal length.
    • Produces aqueous humor.

The Inner Layer of the Eye

• Retina:

  • Contains photoreceptors for detecting light.
  • Composed of two layers:
    • Neural Layer: Thicker, detects photons.
    • Pigmented Layer: Absorbs stray light, maintains retina.

• Macula and Fovea Centralis

  • Fovea Centralis: Center of the macula, provides sharpest visual acuity.

• Blind Spot

  • Area with no photoreceptors.
  • Location of the optic disk sending signals through the optic nerve.

Additional Structures

• Vitreous Body:

  • Transparent gel behind the lens in the posterior chamber.
  • Contains the hyaloid canal, a fetal remnant.

• Aqueous Humor:

  • Located in the anterior chamber.

• Lens:

  • Positioned between the vitreous body and the pupil.