The eye

• What is the primary function of the eye?


  To enable vision by detecting light intensity and color
• What are the key structures of the eye and their functions?

  • Retina: Contains photoreceptors (rods and cones) that convert light into electrical signals.
  • Optic Nerve: Transmits signals from the retina to the brain.
  • Sclera: Protective outer layer that maintains shape.
  • Cornea: Refracts light rays to focus on the retina.
  • Iris: Controls pupil size to regulate light entry.
  • Ciliary Muscles: Adjust lens shape for focusing.
  • Suspensory Ligaments: Connect ciliary muscles to the lens.
• What is the function of the retina?


  It contains photoreceptors that detect light and convert it into electrical signals
• What are the two types of photoreceptors in the retina?


  Rods and cones
• What is the role of rods in vision?


  They are sensitive to dim light, enabling night vision
• What is the function of cones in the eye?


  They are responsible for color vision and detail in bright light
• What does the optic nerve do?


  It transmits electrical signals from the retina to the brain
• What is the sclera?


  The white, protective outer layer of the eye
• What is the function of the cornea?


  It refracts light rays to help focus them on the retina
• What does the iris do?


  It controls the size of the pupil, regulating light entry
• What is the role of ciliary muscles in the eye?


  They adjust the shape of the lens for focusing
• What do suspensory ligaments do?


  They connect the ciliary muscles to the lens and aid in shape adjustment
• What happens during accommodation for near objects?


  • Ciliary muscles contract
  • Suspensory ligaments loosen
  • Lens becomes thicker and refracts light rays strongly
• What happens during accommodation for distant objects?


  • Ciliary muscles relax
  • Suspensory ligaments are pulled tight
  • Lens is thinner, refracting light rays slightly
• What is myopia?


  Short-sightedness where light rays focus in front of the retina
• How is myopia corrected?


  With concave lenses that diverge light rays
• What is hyperopia?


  Long-sightedness where light rays focus behind the retina
• How is hyperopia corrected?


  With convex lenses that converge light rays
• What are the modern treatments for vision correction?

  • Spectacle lenses: Refract light to correct vision
  • Contact lenses: Available in hard and soft varieties
  • Laser surgery: Alters cornea shape to correct errors
  • Replacement lenses: Used for cataract treatment or severe issues