The Structure of the Eye

Overview

• The eye's structure is composed of various parts that work together to capture light and convert it into images.
• Key components: sclera, cornea, conjunctiva, aqueous humour, lens, ciliary body, iris, pupil, vitreous humour, retina, optic nerve, choroid, fovea, and macula.
• Key functions:
  • Cornea and lens: Bend light.
  • Iris: Controls light intake.
  • Retina: Transforms light into neural signals for the brain.

Detailed Structure

Sclera

• The white part of the eye, forming the substance of the eyeball.
• Protects the eye and serves as an attachment point for muscles.

Cornea

• Transparent, located at the front of the eye.
• Protects the eye and bends light slightly.
• Protected by a thin layer of epithelial cells called the conjunctiva.

Conjunctiva

• Thin layer of epithelial cells.
• Protects the cornea from friction and helps keep it moist.

Aqueous Humour

• Water and salt-filled chamber in the anterior eye.
• Provides nutrients and maintains eye pressure.

Lens

• Bi-convex, changes shape to focus light.
• Shape changed by the ciliary body.

Ciliary Body

• Consists of suspensory ligaments and ciliary muscles.
• Adjusts the lens shape and secretes aqueous humour.

Iris and Pupil

• Iris: Colored part of the eye, controls pupil size.
• Pupil: The opening controlled by the iris.

Vitreous Humour

• Jelly-like substance fills the posterior chamber.
• Supports the eye structure and helps focus light.

Retina

• Converts light into neural signals.
• Contains photoreceptors (rods and cones).

Optic Nerve

• Transmits signals from the retina to the brain.

Choroid

• Network of blood vessels nourishing the eye.
• Pigmented black in humans, aiding in light absorption.
• In some animals, reflects light to aid night vision.

Fovea and Macula

• Fovea: Dimple in the retina filled with cones, providing high detail vision.
• Macula: Region of the retina with the fovea at its center.

Additional Information

• Red-eye effect: Caused by flash reflecting off the blood-rich retina.
• Vision underwater: Goggles help maintain correct light refraction by adding air in front of the eye.

Conclusion

Understanding the structure of the eye helps comprehend how vision works and how different parts contribute to processing visual information.