Eye Flashcards
What is the cornea and what is its function?
A transparent window with a convex shape and a high refractive index.
It does most of the eye’s focusing.
What is the function of the lens?
Acts as a fine focus and is controlled by muscles.
When the muscles contract, tension is released and the lens takes on a fat, more spherical shape.
When the muscles relax, the lens is pulled into a thin, flatter shape.
This changes the focal length of the eye.
What is the function of the retina and what does it contain?
Images are formed here.
Contains light-sensitive cells called rods and cones.
What does the yellow spot contain?
This is the part of the retina with the highest concentration of cones.
Its a particularly sensitive region of the retina.
In the centre of the yellow spot is the fovea.
What is the function of the optic nerve?
Carries signals from the rods and cones to the brain.
What is the far point?
The furthest distance the eye can focus on comfortably.
For normal sighted people, this is infinity.
What is the near point?
This is the closest distance that the eye can focus on.
For young people, this is about 9 cm.
Why are rods and cones called photoreceptors?
They detect light and convert it to an electrical signal
What is spatial resolution?
This is a measure of the ability to form separate images of objects that are close together.
When can two objects be distinguished from each other?
If there is at least one rod or cone between the light from each of them. This is true as long as the rod or cone between the image doesn’t share an optic nerve with any of the rods and cones detecting the images.
