glaucoma

Question 1

what is glaucoma ?

Answer 1

optic nerve damage that is caused by a significant rise in intraocular pressure.

The raised intraocular pressure is caused by a blockage in aqueous humour trying to escape the eye.

Question 2

wheres does the aqueous humor of the eye drain?

Answer 2

• through the trebecular network and the canal of schlem

Question 3

what is the normal pressure in the eye?

Answer 3

10-21mmhg

the trabecular network creates the increase in pressure by introducing resistance

Question 4

what is the pathophysiology of open angle glaucoma?

Answer 4

gradual increase in the resistance of the trabecular network leads to gradually increasing pressure in the eye

this causes cupping of the optic disc, an optic cup >0.5 of the optic disc is abnormal and suggests glaucoma

Question 5

what are risk factors for open angle glaucoma?

Answer 5

• increasing age
• family history
• black ethnic origin
• near sightedness (myopia)

Question 6

how will someone with open angle glaucoma present?

Answer 6

• asymptomatic
• loss of peripheral vision
• fluctuating pain
• blurred vision
• headaches
• halos surrounding lights-> worse at night

Question 7

how can the intraocular pressure be measured?

Answer 7

• non contact tonometry, less accurate. involved spraying puff into eye and if patient reacts means they dont have too much pressure in the eye, if they dont react it means the eye is already full of pressure
• more acurate method is goldman application tonometry. this is the gold standard and actually needs to be pressed down on the cornea

Question 8

how can glaucoma be diagnosed?

Answer 8

1. goldman application tonometry showing increased intraoccular pressure
2. fundoscopy showing cupping
3. loss of peripheral fields

Question 9

how is open angle glaucoma managed?

Answer 9

• prostaglandin analongues - latanoprost which increases the uveoscleral outflow
• topical beta blockers like timolol which reduce the production of aqueous humour
• carbonic anhydrase inhibitors-dorzolomide which decreases production of aqueous humour
• sympathomimetics like brimonidine, which decrease productionof aqueous humour
  and increase uveoscleral outflow

Question 10

when is treatment started?

Answer 10

when intraocular pressure is >24mmhg

Question 11

what are the side effects of latanoprost?

Answer 11

• eyelash growth
• eyelid pigmentation
• iris pigmentation-> brown

Question 12

what type of surgery can be used if eyedrops are ineffedctive?

Answer 12

trebeculectomy

- creating a new channel for aqueous humour to drain from the eye