Vision Flashcards
Conjunctiva
mucosal epithelium that forms a sac when eyes are shut
covers sclera
secretes mucous
lubricates surface
Disorders of the conjunctiva
conjunctivitis
pinguecula
conjunctivitis
disorder of conjunctiva
dry eye
allergies
viral and bacterial infections
Pinguecula
disorder of conjunctiva
degeneration of conjunctiva
Cornea
transparent part of the eye
powerful refractive component 2/3 eye power
Five layers
flattens in periphery to improve imager and reduce aberrations
flattest at horizontal meridian
Layers of the cornea
five: epidermis - healing stroma - collagen, transparency endothelium - maintain transparency bowman's - collagen Descemet's - basement membrane
Disorder of cornea
Keratitis
Keratitis
inflamed cornea
Sclera
white part of eye blue in young - collagen disease yellow in elderly - jaundice / lipid deposits protects and supports eyeball three layers
layers of the sclera
three:
episclera - blood vessels
stroma - irregular collagen fibres (opaque)
lamina fusca - thin pigmented connective tissue
disorders of the sclera
episcleritis
scleritis
Episcleritis
harmless form of red eye
scleritis
painful red eye which can damage sight
limbus
transition zone between cornea and sclera
aqueous humour drainage via the trabecular meshworks
Aqueous humor
transparent blood like fluid
feeds cornea and crystalline lens
secreted by ciliary processes
disorders of the limbus
glaucoma
glaucoma
blockage of the trabecular meshworks
exaggerated cupping
tonometry
measures IOP
keratometry
measure curvature of cornea
iris
vascular layer of the eye
coloured (melanin)
forms pupil which controls light entering eye
sphincter pupillae
constricts pupil
miosis
dilator pupillae
dilates pupil
mydriasis
disorders of the iris
iritis
occurs with anterior uveitis
iritis
very serious red eye
uveal tract
iris
ciliary body
choroid
retina
macula
fovea
optic disc
ciliary body
ring of tissue
vascular layer
ciliary muscle and process
ciliary muscle
focus eye (accomodation) via attachments to lens
ciliary process
secrete aqueous humour
disorders of the ciliary body
anterior uveitis
anterior uveitis
red eye
anti-glaucoma drugs
reduce aqueous humour production
choroid
posterior vascular layer
three layers:
bruch’s membrane - passes material to and from retina
vascular layer - nourish retina / blood supply
suprachoroid - melanin / absorbs stray light
disorders of the choroid
choroiditis (with posterior uveitis)
macular degeneration
choroiditis
with posterior uveitis
inflammation of choroid
threat to sight
macular degeneration
caused by dysfunction of bruch’s membrane
retina
inner neural layer
layer include:
retinal pigement epithelium - nourish photo receptors
photo receptors - rods in periphery, cones in fovea, bipolar and ganglion integrate and process photo receptor signals
cones
in fovea
object identification
high resolution
colour vision
rods
in periphery
object detection
high sensitivity
contrast, brightness, motion
disorders of the retina
retinal detachment
diabetic retinopathy
hypertensive retinopathy
macular degeneration
crystalline lens
refractive component - variable - 1/3 eye power
flatter in periphery
grows through life
made up of:
lens capsule - changes shape / accommodation
cortex - youngest lens fibres
nucleus - oldest fibres
what maintains the transparency of the crystalline lens
crystallins
regular arrangement on lens fibres
lack of organelles
antioxidants