Eyes

• Cornea

  • window of the eye, the outer thin membrane of eyeball
• Conjunctiva

  • thin tissue in the inner surface of eyelids
• Sclera

  • visible white area of the eye (usually known as: the eyeball)
• Pupil

  • black circle in the middle of the eye
• In a dark room, the pupil gets bigger to let in more light. This helps the eye see better.
• When a flashlight shines in the eye, the pupil gets smaller. This protects the eye and shows the person is alive.
• During excitement, the pupil gets bigger. Strong feelings like fear or attraction cause this.
• Iris

  • the colored circle of the eye
• Retina

  • the inner surface of the eye
  • The back part of the eye where images form
• Blind spot

  • the point in retina where optic nerves exit
• Optic Nerve

  • carries images from retina to brain
• Myopia 

  • Nearsightedness - can see nearby objects clearly, but distant objects are blurry
  • Use concave lenses
• Hyperopia 

  • Farsightedness - Can see distant objects clearly, but nearby objects are blurry
  • Use convex lenses
• Presbyopia 

  • Common patients are aged 40 and above
  • Called “aging eyes”
  • Eyeball is short (shaped like an oblong) and image formed is at the back of retina
  • If someone's glasses have a small rectangle at the bottom, it usually means they have this
• Astigmatism 

  • Cannot focus simultaneously on horizontal and vertical lines 
  • Can see blurry images
  • Scattered focus of light
• Camera

  • ability to produce a permanent record of images invented by Roger Bacon
• Magnifying Glass

  • concave lens that produces enlarged image objects at a distance less than its focal length
• Microscope

  • uses more than one concave lens to achieve a greater magnification of specimen, usually microorganisms (uses more than 2 concave lenses)
• Telescope

  • a device that enables people to see distant objects, especially heavenly bodies