What is an optician? Dispenses eyeglasses and contact lenses from prescription
supplied by others
What are the six extraocular muscles & their functions? medial rectus - inward
rotation,
inferior rectus - downward rotation,
lateral rectus - outward rotation,
superior rectus - upward rotation,
superior oblique - incyclotorsion (down/inward),
inferior oblique - excylptorsion (up/outward)
What does strabismus mean? Misalignment of the eyes that causes vision to be
disturbed. Happens when extraocular muscles do not work in a coordinated manner.
What is ptosis? drooping of the upper eyelid
What is the fovea? Center part of macula that has ONLY cones
What are floaters? Small particles of dead cells and other debris in vitreous and
collagen fibers from vitreous degeneration. Experienced by patients as spots or cobwebs
What are the 2 types of photoreceptor cells & what are their functions? Rods â€â€>
"night vision" & peripheral
Cons â€â€> sharp central vision & perception of color
What is the vitreous? Clear jelly-like substance that fills the intra-ocular cavity
behind the lens
Describe how the eye converts light rays to a perceived image Light rays
reflected from an object are focused by the cornea and lens to produce an upside down image on
the light-sensitive retina. The retina converts the image to electrical impulses which are carried
by the optic nerve to the brain's visual cortex where they produce sensation of light
Name 4 structures in the adnexa The orbit,
extraocular muscles,
eyelids,
lacrimal apparatus
Name three functions of the eyelids Protect eye from injury, exclude light, aid in
lubricating ocular surface
Name three layers of the eyelids Outer layer of skin, middle layer of fibrous
tissue and muscles, inner layer of tissue (conjunctiva)
What are the two primary functions of the lacrimal apparatus? To produce and
drain tears