Common Conditions of the Eye Flashcards
what part of the boy orbit is easily fractured?
the medial and inferior walls
21 year old is complaining of double vision, they were in a fight a weeks ago.
On examination their right eye elevates but their left does not.
What might the problem be?
the blunt trauma to the eye may have caused a blow out fracture.
palpate the orbital rims, there will be no fracture but a CT/MRI may show a blow out fracture and tethering effect.
in a patient who has a had a blow out fracture on their right eye what symptoms and signs might you expect to see?
inability to elevate the right eye and reduction in sensation on palpation round the right eye (due to the sensory branch of the maxillary nerve through the infraorbital foramen being affected.
what leads to a staring condition in thyroid disease?
orbital fat hypertrophies and can fibrose
where do eyelid normally sit in relation to eye surface anatomy?
upper: below the corneascleral junction
lower: at the level of the corneasceral junction
a previously well patient has a two hour history of blurred vision, a red swollen eye with no movement which this progresses to complete loss of vision in that eye.
the optic disc is swollen and engorged and there is dilated veins.
what could be wrong with this patient?
infection has spread through the emissary veins to the cavernous sinus leading to cavernous sinus thrombosis and compromised venous drainage of the orbit.
This is an emergency.
what is a coloboma?
a hole in one of the structures of the eye.
why may blunt trauma to the eye cause painless increasing blindness in that eye?
there is a peripheral tear in the retina and the vitreous gel get liquefied. the liquid vitreous pushes through the retinal tear and it detaches it.
describe conjunctivitis
> self limiting infection
red, watering eyes
no loss of vision (unless infection spreads to the cornea)
what is ptosis?
drooping of the eyelid (can be caused by 3rd cranial nerve damage)
blockage of what glands cause hordeolum externa?
subcutaneous gland
blockage of what glands cause hordeolum internum?
mybomian glands
what is the treatment for stye/hordeolum?
> warm compress
eyelid hygiene
surgical incision and curettage (puss drains out)
what do corneal pathologies frequently lead to?
opacification of the cornea
is a corneal ulcer an inflammatory or non-inflammatory corneal pathology?
inflammatory
is dystrophies an inflammatory or non-inflammatory corneal pathology?
non-inflammatory
why does infectious corneal ulceration need aggressive management?
to prevent scarring
what can non infectious corneal ulcers be caused by?
> trauma
corneal degenerations
dystrophy
describe corneal dystrophies
> bilateral > opacifying > non-inflammatory > genetically determined > can be due to accumulation of substances such as lipids
how may corneal dystrophies present?
> in first to fourth decade
with decreased vision
starts in one layer of the cornea then spreads to others
why do cataracts develop?
> older fibres never shed so are compacted in the middle
no blood supply to the lens so it relies on diffusion
lens absorbs harmful UV rays and get damaged (which are opaque)
how is cataracts treated?
> surgery
small incision and lens capsule is opened
cataractous lens removed by emulsification
plastic lens is placed in capsular bag
what can cause cataracts?
> trauma
medication (steroids)
in utero due to malnutrition or virus
how is the intraocular pressure affected in glaucoma?
it is raised
what is the pathology of raised intra orbital pressure?
there is pressure on nerve fibres on the surface of the retina so they die out causing visual field defects and an altered field of vision and ultimately blindness.
how does the optic disc appear in glaucoma?
unhealthy, pale and cupped
name the triad signs for the diagnosis of glaucoma
> raised IOP
visual field defects
optic disc changes on the opthalmoscopy
what is the management for glaucoma?
> eye drops to decrease intra-orbital pressure (prostaglandins analogues, beta-blockers, carbonic anhydrase inhibitors)
laser trabeculoplasty
trabeculectomy
describe the symptoms and signs of angle closure glaucoma?
> sudden onset > pain > vision loss/blurring > headaches > red eye > opaque cornea > ac shallow and angle is closed > pupil mid-dilated
why does the angle close?
> functional block (small eye/large lens)
mid-dilated pupil - the periphery of the iris crowds around the angle and outflow is obstructed
iris sticks to the pupillary border preventing reaching AC leading to iris ballooning anteriorly and obstructing angle
how would you manage angle closure glaucoma?
> IV infusion-carbonic anhydrase inhibitors
analgesics
constrictor eye drops
betablocker drops-timolol
steroid eye drops (dexamethasone)
iridotomy (laser) of both eyes to bypass the blockage
describe the pathology of angle open glaucoma
the drainage through the trabecular meshwork is blocked leading to gradual painless build up of intraocular pressure, primary open angle glaucoma.
describe the pathology of angle closure glaucoma
some event on a predisposed eye leads to peripheral iris blocking the angle so aqueous cant drain. the increase in intraocular pressure is sudden leading to red eye and severe pain presenting as an emergency.
what is uveitis?
inflammation of the uvea
what types of uvea are there?
> anterior uveitis - iris
intermediate uveitis - ciliary body inflamed
posterior uveitis - choroid inflamed
what are the causes of uveitis?
> isolated illness
autoimmune disease
infection (TB)
associated with systemic disease (ankylosing spondylosis)
describe the pathophysiology of anterior uveitis
inflamed anterior uvea leaks plasma and white blood cells into the aqueous humour and can be seen during a split lamp examination. the eye is red and painful with visual loss.
cells in the anterior chamber may settle inferiorly
describe the pathophysiology of intermediate uveitis
the ciliary body is inflamed and leaks cells and proteins leading to a hazy vitreous and vision
describe the pathophysiology of posterior uveitis
choroid is inflamed and as it sits under the retina inflammation spreads causing blurred vision
