What is an optician? correct answers Dispenses eyeglasses and contact lenses from prescription supplied by others What are the six extraocular muscles & their functions? correct answers 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? correct answers Misalignment of the eyes that causes vision to be disturbed. Happens when extraocular muscles do not work in a coordinated manner. What is ptosis? correct answers drooping of the upper eyelid What is the fovea? correct answers Center part of macula that has ONLY cones What are floaters? correct answers 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? correct answers Rods —> "night vision" & peripheral Cons —> sharp central vision & perception of color What is the vitreous? correct answers Clear jelly-like substance that fills the intra-ocular cavity behind the lens Describe how the eye converts light rays to a perceived image correct answers 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 correct answers The orbit, extraocular muscles, eyelids, lacrimal apparatus Name three functions of the eyelids correct answers Protect eye from injury, exclude light, aid in lubricating ocular surface Name three layers of the eyelids correct answers 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? correct answers To produce and drain tears