Common Conditions of the Eye Flashcards
what is nuclear sclerosis?
lens opacification, makes objects appear less clear, and also makes patient see more of the red spectrum
what is the most common disease of the eye?
cataract(Lens opacification)
Why do cataracts develop?
Older fibres are never shed
lens depends entirely on diffusion for nutrition
Absorbs harmful UV rays preventing them from damaging retina but in the process, get damaged themselves
Damaged lens fibres- opaque
what are the different types of cataracts?
Immature cortical cataract – seen as spoke like opacities
Mature cataract
Steriod – induced cataract
Traumatic cataract
Nuclear sclerosis type of cataract
Sutural + Zonular cataract – types of childhood cataract
what is the management of cataract?
PCIOL Surgery – (day case) small incision -lens capsule opened
cataractous lens removed by emulsification (phacoemulsification)
plastic lens placed in capsular bag
what is glaucoma?
Raised intraocular pressure-IOP
2nd most common cause of blindness
what are the consequences of raised IOP?
Pressure on nerve fibres on surface of retina die out-visual field defects (optic disc appears pale and cupped)
Ultimately all nerve fibres are lost, which results in blindness.
what three things are required for it to be glaucoma?
- Raised IOP
- Visual field defects
- Optic disc changes on ophthalmoscopy
what is the management of POAG(Primary Open Angle Glaucoma)?
Eye drops to decrease IOP: -Prostaglandin analogues -Beta-blockers -Carbonic anhydrase inhibitors Laser trabeculoplasty Trabeculectomy surgery
what are symptoms of Angle Closure Glaucoma?
Sudden onset, painful, vision lost/ blurred; headaches
O/E – Red eye, cornea often opaque as raised IOP drives fluid into cornea
AC shallow, and angle closed
Pupil mid-dilated
IOP severely raised
why does the angle close in glaucoma?
- Functional block in a small eye – large lens
- Mid-dilated pupil, periphery of iris crowds around angle and outflow is obstructed
- Iris sticks to pupillary border which prevents reaching AC. Leads to iris balooning anteriorly and obstructing angle.
what is the management of an acute episode of the angle closure of glaucoma?
Decrease IOP:
IV infusion with or without oral therapy
Analgesics
Constrictor eye drops
If no contraindication beta-blocker drops
Steroid eye drops
Iridotomy (laser) - both eyes - to bypass blockage
what is the difference between the mechanism of open angle vs angle closure glaucoma?
In open angle glaucoma the drainage through the trabecular meshwork is blocked
In angle closure glaucoma, some event on a predisposed eye leads to the peripheral iris blocking the angle, therefore aqueous can’t drain
how does the difference in mechanism in open angle vs angle closure affect the build up of IOP?
open angle, leads to a gradual, painless build up of IOP
angle closure, leads to sudden increase in IOP leading to a red eye, and severe pain
what is keratoplasty?
corneal transplantation
what are the 2 causes of an inflammatory corneal ulcer?
- Infectious - needs aggressive management to prevent spread/scarring
- Non-infectious ulcers due to trauma, corneal degenerations or dystrophy
describe the group of diseases causing non-inflammatory corneal dystrophies?
Bilateral
Opacifying
Mostly genetically determined
Sometimes due to accumulation of substances such as lipids
what is lattice (stromal) dystrophy?
autosomal dominant
Deposition of amyloid material in the corneal stroma
Patient presents with eye irritation, photosensitivity, pain, blurred vision
what is Fuch’s endothelial dystrophy?
Asymmetrical bilateral progressive oedema of the cornea.
Occurs in the elderly
when enough endothelial cells die- opacification of the cornea
what is uveitis?
inflammation of uvea
what are the different types of uveitis?
Anterior uveitis – iris with or without ciliary body inflammed
Intermediate uveitis – ciliary body inflammed
Posterior uveitis – choroid inflammed
what are the causes of uveitis?
Isolated illness
Non-infectious autoimmune causes – eg HLA-B27
Infectious causes eg TB
Associated with systemic diseases – eg ankylosing spondylosis
describe anterior uveitis
An inflammed anterior uvea (iris) leaks plasma and white blood cells into aqueous humor
The eye is red, painful, with visual loss
describe Intermediate uveitis
ciliary body is inflammed and leaks cells and proteins
This leads to a hazy vitreous
hazy vision
describe posterior uveitis
choroid is inflammed.
Since the choroid sits under the retina, the inflammation frequently spreads to the retina causing blurred vision
what is Conjunctivitis?
Self-limiting bacterial or viral infection of the conjunctiva. Red, watering eyes, + discharge. No loss of vision as long as infection does not spread to cornea
what does an external stye/hordeolum affect?
sebaceous glands of an eyelash
what does an internal stye/hordeolum affect?
meibomian glands
how can an external stye/hordeolum occur?
infection of the hair follicle of the eyelash
how can an internal stye/hordeolum occur?
blockage and infection of the Meibomian glands
