The Eye (T)

• What is the main function of the eye?

  The eye is a sense organ that detects light intensity and color.
• What are the main parts of the eye and their functions?

  • Cornea: Starts focusing light
  • Iris: Controls the size of the pupil
  • Pupil: Allows light to enter the eye
  • Lens: Focuses light onto the retina
  • Retina: Contains receptor cells for light
  • Sclera: Protects the eye
  • Ciliary muscles and suspensory ligaments: Help focus on distant or near objects
• How does the lens of the eye adapt to focus on objects?

  The lens changes shape to focus on distant or near objects.
• What is the role of the retina in the eye?

  The retina contains receptor cells that detect light intensity and color.
• What happens to the pupil in low light conditions?

  The pupil enlarges to allow more light to enter the eye.
• What is the reflex action that occurs when entering a dark room?

  The iris muscles contract to enlarge the pupil, allowing more light in.
• What occurs when entering a bright room?

  The pupil becomes smaller to reduce light entering the eye.
• What is the process of accommodation in the eye?

  • The lens changes shape
  • Focuses light on the retina
  • Allows vision of distant or near objects
• What is the function of the optic nerve?

  The optic nerve transmits electrical impulses from the retina to the brain.
• What is the sclera?

  The sclera is the tough outer structure that protects the eye.
• How do the ciliary muscles and suspensory ligaments work together in the eye?

  • Ciliary muscles contract or relax
  • Change the shape of the lens
  • Allow focusing on distant or near objects
• What is the term used to describe the ability of the lens to change shape to focus on near or distant objects?

  Accommodation
• What are the main components involved in the focusing of light onto the retina?

  • Cornea
  • Lens
  • Ciliary muscle
  • Suspensory ligaments
  • Retina
• What role does the cornea play in focusing light?

  It carries out a fixed focus of light rays.
• How does the ciliary muscle affect the lens during accommodation?

  It changes the thickness of the lens.
• What are the suspensory ligaments connected to?

  They are connected to the lens.
• What happens to the lens when the ciliary muscle contracts?

  • Suspensory ligaments loosen
  • Lens becomes thicker
  • Light rays are refracted more strongly
• What happens to the lens when the ciliary muscle relaxes?

  • Suspensory ligaments are pulled tight
  • Lens becomes thinner
  • Light rays are only slightly refracted
• Why do light rays from distant objects need to be focused only a small amount?

  Because they are nearly parallel.
• What is the difference between long-sightedness and short-sightedness?

  Long-sightedness affects near vision; short-sightedness affects distant vision.
• How is long-sightedness treated?

  • Glasses with convex lenses
  • Partially focus light before it enters the eye
• What causes long-sightedness in some individuals?

  Eyeball too short or lens less elastic.
• How is short-sightedness treated?

  • Glasses with concave lenses
  • Partially unfocus light before it enters the eye
• What causes short-sightedness in individuals?

  Eyeball too long or lens too thick.
• What are some alternatives to glasses for correcting vision?

  • Hard contact lenses
  • Soft contact lenses
• What is one recent treatment for long and short-sightedness?

  Laser surgery to change the shape of the cornea.
• What can be done to replace the lens inside the eye?

  • Use an artificial lens