Parts of the eye and their function Flashcards
What is the function of the cornea?
Refracts light - bends it as it enters the eye
what is the function on the iris?
controls how much light exeter’s the pupil
what is the function of the lens?
further refracts light to focus it onto the retina
what is the function of the retina?
contains light receptor cells that sense light
what is the function on the sclera
tough white outer layer of the eye -it helps protect the eye from injury
What is the eye?
the eye is a sense organ containing receptors sensitive to light intensity and colour
accommodation
the process of changing the shape of the lens to focus on near or distant objects
what happens when we want to focus on a near object?
the lens becomes thicken which allows the light rays the refract(bend) more strongly
what happens when we want to see more distant objects?
the lens becomes thicker which allows the light rays to refract slightly
what is short sightedness?
someone who is short sighted can see near objects clearly, but cannot focus properly on distant objects
how can short sightedness be corrected?
by placing a concave lens in front of the eye
how is short sightedness caused?
the eyeball being elongated - so that the distance between the lens and the retina is too great.
the lens being too thick and curved - so that light is focused in front of the retina.
what is long sightedness?
Someone who is long-sighted can see distant objects clearly, but they cannot focus properly on near objects.
how can long sightedness be corrected?
laser eye surgery, or contact lenses
what are the causes of long sightedness?
the eyeball being too short - so the distance between the lens and retina is too small
a loss of elasticity in the lens - meaning it cannot become thick enough to focus (which is often age-related)
