Eye Conditions Flashcards
What is Retinal Detatchement
Fluid gets into potential space between the INNER 9 layers of reinta and the OUTER 10th layer
Results in blindness is painless and can reslut from trauma
What is Cataract
Lens Opacification
What is Myopia
Shortsightedness
Image forms SHORT of retina
Close objects look clear, distant objects are blurry
What is Hyperopia
Long-sightedness
Image forms past the the retina
Close objects are blurry, distant objects are clear
What is Presbyopia
Old age Long-sightedness
Lens becomes less mobile/elastic so when ciliary muscles contract it is less able to change its shape
What is perfect vision
Emmetropia
What is Strabismus
Squint/Misalignment of the eyes
Describe the two types of Strabismus
Esotropia - Convergent squint
Exotropia - Divergent squint
Functional consequence of squint
Amblyopia/lazy eye - Brain suppresses the image of one eye leading to poor vision in the eye without any pathology (correctable in early years via eye patch; forcing “lazy eye to work”)
Diplopia/Double vision - Usually occurs in squints occuring as a result of nerve palsies
Why does Cataracts develop
Embryological/foetal Lens fibres are never shed - compacted in the middle
Absorbs UV rays, preventing them reach retina but damages Lens instead
Can arise from trauma
Damages lens fibres => Opague => Cataract
Treatment of cataracts
Surgery (day case) - Small incision => lens capsule opened => cataractous lens removed by emulsification => plastic lens placed in capsular bag
What is Glaucoma
Raised Intraocular Pressure (2nd most common cause of blindness)
Consequence of Raised IOP
Pressure on nerve fibres on retina => nerves die out => visual field defects
Glaucoma is usually picked up on routine eye exams, what would be seen during opthalmascopy
Optic disc appears pale and cupped
Three signs of Glaucoma
Raised IOP
Visual Field Defects
Optic disc changes on opthalmoscopy
Management of POAG
Eye drops to decrease IOP
- Prostaglandin Analogues
- Beta-blockers
- Carbonic anyhydrase inhibitors
Laser trabeculoplasty
Trabeculectomy surgery
Two types of Glaucoma
Primary Open Angle Glaucoma (POAG)
Angle Closure Glaucoma
Symptoms of Angle closure glaucoma
Sudden onset
Visson loss/blurred
Headaches (often confused with migraine)
Signs of Angle closure glaucoma
Red eye
Cornea often opague as severely raised IOP drives fluid into conrnea
Anterior Chamber shallow and angle is closed
Pupil mid-dilated
Why does the angle close
Functional block in a small eye - large lens prevents fluid reaching the Anterior chamber
Mid-dilated pupil => periphery of iris crowds around angle and outflow is obstructed
Iris sticks to pupillary border => prevents Fluid reaching Anterior chamber => iris ballooning anteriorly and obstructin gngle
Management of acute Glaucoma episode
Decrease IOP - IV infusion with/without oral therapy of CARBONIC ANHYDRASE (acetazolamide)
Analgesics
Antiemetics
Constrictor eye drops - pilocarpine
Beta-blockers (timolol) if not contraindicated
Steroid eye drops (dexamethasone)
Iridotomy (laser) - BOTH EYES - to bypass blockage
Primary open angle glaucoma (POAG) vs Angle closure glaucoma (ACG)
POAG drainage via Trabecular meshwork is blocked => GRADUAL and PAINLESS raised IOP
ACG Peripheral iris blocks the angle therefore the aqueous can’t drain => IOP increase is SUDDEN and severely PAINFUL
2 types of corneal pathology
Inflammatory - corneal ulcers
Non-inflammatory - dystrophies
2 types of corneal ulcers
Infective - Viral/bacterial/fungal infection of cornea
Non-infective - Trauma/corneal degenerations/dystrophy
