structure of the eye

• what does the optic nerve do

  sends signals to the brain
• retina function

  a light sensitive layer which sends signals to the optic nerve
• ciliary muscle function

  pulls the lens for focusing
• iris function

  controls the amount of light entering the eye
• cornea function

  lets light into the eye and begins focusing
• pupil function

  lets light through to the lens
• suspensory ligament function

  holds the lens in place
• lens function

  focuses light onto the retina
• for distant objects

  the ciliary muscles relax and the suspensory ligaments contract making the lens pull thin
• for close objects

  the ciliary muscles contract and the suspensory ligaments relax to allow the lens to go fat
• what is accommodation

  the adjusting of the lens for close and far objects
• myopia is

  short sightednes- where there is too much refraction so the fical point is in front of the retina
• how do you fix myopia

  concave glasses
• what is hyperopia

  long sightedness- too little refraction so the focal point is behind the retina
• how can you fix hyperopia

  convex glasses
• accommodation=

  1/near distance - 1/far distance
• in dim light..

  circular muscle relax and radial muscles contract
• in bright light

  circular muscles contract and radial muscles relax