Common conditions of the eye Flashcards
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
if the blood vessels in the iris begin to leak where will the leaked fluid go?
into the aqueous humor
what is anterior uveitis?
iris with or without ciliary body inflamed
what is intermediate uveitis?
ciliary body inflamed
what is posterior uveitis?
choroid inflamed
how does a patient with lattice dystrophy present?
eye irritation
photosensitivity
pain
blurred vision
what can cause uveitis?
isolated illness
associated with systemic diseases such as ankylosing spondylosis
can be caused be infectious and non infectious disease
what is the pathophysiology of anterior uveitis?
inflamed iris leaks plasma and WBCs into AH
how does an eye with anterior uveitis appear?
red
painful
visual loss
what is the pathophysiology of intermediate uveitis?
ciliary body is inflamed and leaks cells and proteins into the vitreous
what are symptoms of intermediate uveitis?
floaters - hazy vision
what is inflamed in posterior uveitis?
choroid
what are symptoms of posterior uveitis?
blurred vision
what is conjunctivitis?
bacterial or viral infection of the conjunctiva
what are symptoms of conjunctivitis?
red watering eyes
discharge
no loss of vision if infection doesnt spread to the cornea
what are the 2 types of stye eye or hordeolum?
external - affecting sebaceous glands of an eyelash
internal - affecting the meibomian glands
what causes an external stye?
infection of the hair follicle of the eyelash
what causes an internal stye?
occurs due to blockage and infection of the meiboman glands
what are the meiboman glands?
sebaceous gland at the rim of the eyelids inside the tarsal plate, responsible for the supply of meibum, an oily substance that prevents evaporation of the eye’s tear film.
how do you treat stye eyes?
warm compress
eyelid hygeine
may need surgical incision
