clinical pathology of the eye Flashcards
what are cataracts?
opacification within the lens
what is the most common cause of cataracts?
increase in age
what is the biggest pre disposing factor to cataracts?
-sun damage
what are some causes of cataracts?
- increase in age
- hypertension
- smoking
- post op and trauma
- metabolic disorders
- genetic
- diabetes
what is glaucoma?
-abnormal increase in pressure in the eye
what is pressure in the eye related to?
-the amount of vitreous fluid and anteriorly aqueous humour
where does fluid in the eye normally drain from?
-in the most anterior part of the eye in the trabecular meshwork and eventually into the Schlemm canal
when does glaucoma occur?
-when there is a blockage in the drainage through the trabecular meshwork or in the canal of Schlemm
what is the most common form of glaucoma?
-primary open angle glaucoma
what is the biggest cause of blindness worldwide?
-primary open angle glaucoma
what causes angle closure glaucoma?
- the drainage through the meshwork ect. is patent
- iris is essentially opposed to the anterior part of the eye and the fluid can’t get passed the meshwork
what is the inset like for primary open angle glaucoma?
-slow onset
how does primary open angle glaucoma typically present?
- gradual onset
- typically asymptomatic
how does closed angle glaucoma present?
- 1/3 of cases are emergency
- acute red eye and visual loss with headache
- nausea and vomiting
- can lose site quickly
what is the treatment for closed angle glaucoma?
-zap a hole in the iris with a laser
what can raised intraocular pressure damage?
-optic disc and nerve
how can you tell raised intra ocular pressure has occurred?
- often will witness ‘cupping’ of the disc
- essentially the edges of the disc become rolled up and the centre becomes depressed
what is papilloedema?
-swelling of the optic nerve/disc
what investigations are done for papilloedema?
-opthalmoscope used
what is papilloedema related to?
-its a non specific finding related to increased intracranial pressure
what is conjunctivitis?
-inflammation of the conjunctiva
how does conjunctivitis present?
- swelling
- redness
- pain
- heat
what causes conjunctivitis?
-usually it is viral but can be bacterial or allergic
how does scleritis present?
- pain in eyes on movement
- may have blurry vision, unexplained tears or notice your eyes are especially sensitive to the light
what other disease is scleritis associated with?
- RA
- lupus
- Sjogren’s syndrome
- scleroderma
- IBD
- Wegener’s granuloma
what is episcleritis?
-inflammation of around the sclera (is superficial)
is episcleritis self limiting?
yes
what is ARMD?
- age related macular degeneration
- an acquired degeneration of the retina
what causes age related macular degeneration (ARMD)?
- no clear cause
- age related and underlying inflammatory process
how does diabetes affect the eye?
hyperglycaemia:
- cause changes to osmotic pressures in the anterior chamber of the eye in front of the lens
- this can cause blurred vision
- can have peripheral neuropathy causing Argyll Robertson Pupil (prostitute’s pupil)
- cataracts
- glaucoma (specifically robotic glaucoma due to new vessel formation in the eye)
- diabetic retinopathy
