Lecture on Human Eye Anatomy and Function

Introduction

• Presenter: Yujin
• Topic: Understanding the Human Eye
• Reference Materials: Exercises available via a link in the description.

Overview of Human Eye Structure and Function

• Sense of Sight: The eye perceives light to visualize objects.
• Stimulus: Light is essential for stimulating eye receptors.

Eye Anatomy

Back Part of the Eye

• Three Layers:
  • Sclera: Outer layer, protective.
  • Choroid: Middle layer, contains blood vessels.
  • Retina: Inner layer, contains receptors for light.
• Important Spots:
  • Fovea (Yellow Spot): Most sensitive to light.
  • Blind Spot: No photoreceptors; no image formation.
• Optic Nerve: Transmits visual information to the brain.

Center of the Eye

• Vitreous Humor: Jelly-like substance maintaining shape.

Front Part of the Eye

• Layers and Components (outer to inner):
  • Conjunctiva: Over sclera, protective.
  • Cornea: First layer, refracts light.
  • Aqueous Humor: Fluid-filled space, transparent.
  • Pupil: Allows light entry.
  • Iris: Controls pupil size, colored part of the eye.
  • Lens: Focuses light onto the retina, held by suspensory ligaments.
  • Ciliary Body: Muscles controlling lens shape.

Functions of Eye Components

• Sclera: Maintains shape and protects.
• Choroid: Supplies nutrients and oxygen.
• Retina: Detects light, transfers signals to the brain.
• Cone Cells: Detect color.
• Rod Cells: Detect black and white.
• Cornea: Refracts light.
• Iris: Adjusts pupil size for light regulation.
• Lens: Focuses light, adjusts for distance.
• Ciliary Body: Adjusts lens thickness.

Mechanism of Sight

• Sequence of light travel: Cornea → Aqueous Humor → Pupil → Lens → Vitreous Humor → Retina → Optic Nerve → Brain.

Optical Illusions

• Discrepancies due to brain interpretation errors, not eye faults.
• Examples: Misperceived line lengths and angles.

Vision Defects

• Short-sightedness (Myopia): Clear near vision, blur at distance, corrected with concave lenses.
• Long-sightedness (Hyperopia): Clear far vision, blur up close, corrected with convex lenses.
• Astigmatism: Uneven cornea causes blurred vision, corrected with cylindrical lenses.

Eye Care

• General practices to maintain good eyesight listed.

Exercises

• Labeling exercises and problem-solving based on understanding eye anatomy and functions.
• Practice drawing lines to correct functions and correlating vision defects to solutions.

Conclusion

• Reinforcement of key eye anatomy and functions.
• Encouragement to use provided exercises for practice.