Common conditions of the eye Flashcards
(43 cards)
what is the most common single cause of blindness worldwide?
cataracts
what happens to older lens fibres?
they accumulate in the middle of the lens
what kinds of cataracts are there?
immature cortical mature steroid induced traumatic nuclear sclerosis childhood
what are the 2 types of childhood cataract?
sutural
zonular
why do childhood cataracts develop?
due to opacification of certain zones of the lens in utero
how are cataracts managed?
surgery
what is the name of the surgery used to implant a new lens after cataract surgery?
posterior chamber intra ocular lens - PCIOL
what is the name of the canal by which aqueous humor drains out of the orbit? (after the trabecular meshwork)
schlemms canal
what is the most common type of glaucoma?
primary open angle glaucoma - POAG
why is POAG difficult to detect?
patients can be asymptomatic for a long period of time
what happens if pressure is applied to the nerve fibres on the surface of the retina
they die out - causing visual field defects
how does glaucoma progress?
- raised IOP
- visual field defects
- optic disc changes on opthalmoscopy
how is glaucoma managed?
eye drops to decrease IOP
laser trabeculoplasty
trabeculotomy surgery
what are some classes of eyedrops that can decrease IOP?
prostaglandin analogues
beta blockers
carbonic anhydrase inhibitors
what happens to the trabecular meshwork in POAG?
it doesnt function normally
where is the AH obstruction in angle closure glaucoma?
anywhere along the drainage pathway
what are some features of angle closure glaucoma?
sudden onset pain lost/blurred vision headaches IOP severely raised red eye, cornea often opaque
why does the angle “close” in AC glaucoma?
- functional block in a small eye - large lens
- mid dilated pupil - periphery of iris crowds around the angle and outflow is obstructed
- iris sticks to pupillary border which prevents reaching Anterior Chamber. leads to iris balooning anteriorly and obstructing angle
how is AC glaucoma managed?
dramatically decrease IOP
iridotomy - both eyes to bypass blockage
what are some methods used to decrease IOP in AC glaucoma?
carbonic anhydrase inhibitor IV infusion analgesia constrictor eyedrops steroid eye drops beta blocker eye drops if no contraindication
what are some causes of infectious corneal ulcers?
viral
bacterial
fungal infection of cornea
what are some causes of non infective corneal Ulcers
trauma
corneal degenerations
dystrophies
what is the pathology of lattice (stromal) dystrophies?
deposition of amyloid material in the corneal stroma
what is the pathology of fuchs endothelial dystrophy?
asymmetrical bilateral progressive oedema - swelling due to the accumulation of fluid in the cornea
