Common Problems of the Eye

• Accommodation: The process of changing the shape of the lens to focus on near or distant objects
• What happens to the eye when you focus on far objects?

  1. Suspensory ligaments are pulled tight
  2. Ciliary muscles slacken
  3. The lens becomes more flat and thin so less light refracts onto retina

  
• What happens to the eye when you focus on close objects?

  1. Suspensory ligaments slacken
  2. Ciliary muscles are pulled tight
  3. The lens becomes more thicker and round so more light refracts onto retina

  
• Myopia: It is short sightedness where you struggle to see far away objects as there is too much refraction of light on the retina. So light is refracts less and converges just in front of the retina.

  
• Hyperopia: It is long sightedness where you struggle to see close objects as there is too little refraction of light on the retina. So light is refracted behind of the retina.

  
• What is the cause of myopia?

  • Lens is too round
  • Eyeball is too long
• What is the cause of hyperopia?

  • Lens is too flat or thin
  • Eyeball is too short
• What type of lens helps with myopia?

  Concave lens as it helps spread light from objects before reaching the eye
• What type of lens helps with hyperopia?


  Convex lens as it helps converge the light from the object on to the retina
• What can help both myopia and hyperopia?

  • Contact lenses
  • Glasses
  • Laser Eye Surgery
  • Replacement lenses
• What are advantages for contact lenses?

  • More convenient
  • No need for glasses
• What are some disadvantages for contact lenses?


  • Can forget to remove before sleeping
  • Needs to be kept sterile everyday
  • More expensive than glasses
  • May get eye infection if not sterilised
• What are some advantages of laser eye surgery?

  • Permanent
  • No need for glasses or contact lenses
• What are some disadvantages of laser eye surgery?


  • Expensive
  • May lead to more damage
  • Takes a while to recover
• What are some advantages of Lens replacement surgery?


  • Permanent
  • Removes blurriness
• What are some disadvantages of Lens replacement surgery?

  • May lead to more damage or infected
  • Expensive