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Understanding the Anatomy of the Eye

May 7, 2025

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.