Ocular Anatomy Flashcards
purpose of eye and visual system
to transform light energy into neural signal that can be perceived by the brain (all structures support this)
outer or fibrous tunic
cornea - principal refracting component so transparency must be maintained; protection against external penetration
sclera - maintains shape of the globe; protects against internal and external factors; provides attachment for EOMs
middle or vascular or uveal tunic (blood system) + function
iris, ciliary body, choroid
inner or neural tunic
retina
layers of the cornea
- Epithelium
- Bowman’s layer
- Stroma
- Descemet’s membrane
- Endothelium
corneal blood supply
avascular - no blood supply (must be transparent)
receives nutrients from diffusion from air, limbal conjunctival capillaries
limbus + function
at corneoscleral junction; transition zone between cornea and conjunctive, and cornea and sclera
- provides nutrients to adjacent tissue, and pathway for drainage of aqueous
aqueous function
maintain IOP
provides nutrients and removes waste from cornea and lens
maintains transparency
lens function
transmit and refract light
- avascular and transparent
- accommodation (change curvature so optical system can change focus)
- UV absorption
cataract
loss of clarity in lens
vitreous function
metabolism of retina and lens
movement of materials within eye
mechanical support
transmission of light (low light scatter)
choroid function
provides nutrients to outer retina
exit for metabolic end products from retina
absorbs excess light
passageway for vessels and nerves heading to anterior segment
vitreous degeneration
leads to formation of liquid-filled cavities and fibrillar strands of vitreous (vitreous floaters)
retina function
neural tunic
- transforms light energy into neural signal
- begins pathway for transmission of signal from eye to brain
photoreceptors + function
rods
- for darker, farther vision
- contrast, brightness, motion
cones
- fine detail, spatial resolution, color vision
rods: cones = 20:1
