Visual Inspection and Basics - Module 2 - Part 2 Flashcards
Problems with the Cornea can lead to…
distorted or blurry vision
To maintain health of the Cornea…
it is important to keep hydrated and get treatment for eye infections.
Wearing protective lenses that shield the cornea from external damage is an important way to prevent traumatic injury.
Iris and pupil
The iris can close quickly to prevent damage to the eye and takes longer to open.
Pigmentation in the eye that gives the iris it’s colour.
Lens and Ciliary Muscle
Lens conditions
The lens focuses light coming into the eye. Its shape is controlled by the ciliary muscle.
The lens, as well as the cornea, is responsible for filtering out some frequencies of light coming into the eye.
Lens - Cataracts and astigmatisms
Aqueous and Vitreous Humor
Conditions
Aqueous humour is a sac of fluid that is between the iris/lens and the cornea. Vitreous humour is a sac of fluid that is between the lens and the retina. Both sacs maintain the shape of the eye, a little like air keeps the shape of a balloon.
Glaucoma
Retina
The screen that light is projected against after passing through the cornea, iris and lens. Covered with cells called photoreceptor cells that convert light to electrical impulses, which our brain turns into an image.
Optic Nerve
exits the eyeball near the back of the retina, off to one side. No photoreceptor cells at that location.
Rods and Cones
photoreceptor cells
both detect different aspects of light
rods detect presence of light
cones detect colours
neither of these cells is dispersed evenly across the retina.
Name of the relatively small area at the back of the retina that contains most of the cone cells?
macula and fovea
Areas of our peripheral vision are sensitive to…
light and movement, but not much detail
Loss of rod cell function could lead to
night blindness, tunnel vision or both
3 different types of cone cells:
- S stands for the short wavelengths (blue/violet range) that can be detected by S cones
- M for the medium wavelengths (green range)
- L for long wavelengths (red range)
Cone cell deficiency
colour blindness
What area of the retina is responsible for central vision?
the Macula, contains both rod and cone cells
What is the central part of the macula that is responsible for the most sensitive part of our vision?
Fovea, high density of cones
