Accommodation - The Eye Flashcards
What is the accommodation reflex
changing thickness of lens to see short and far clearly
Which two parts of the body control the lens shape
the ciliary muscles
the suspensory ligaments
Why do we need the lens and cornea
refract light so it focuses directly on the fovea(retina)
Light rays from objects far away are almost what once hitting the eye
parallel
Light rays from objects close are what when hitting the eye
widely angled
What does the lens need to be like when looking at things close
FAT THICK to increase refractive power
What does the lens need to be like when looking at things far away
SKINNY to decrease level of refraction
In order to focus on things far away what do the ciliary muscles and suspensory ligaments do and how does it effect the lens
ciliary muscles relax
suspensory ligaments are pulled taught to pull the lens tight
decreasing its thickness
In order to focus on things up close what do the ciliary muscles and suspensory ligaments do and how does it effect the lens
ciliary muscles contract inwards
suspensory muscles therefore slackens the lens
allowing it to return to its normal fatter size