Glaucoma

Question 1

what is glaucoma?

Answer 1

Progressive optic neuropathy
Characterised by optic nerve head (disc) changes and corresponding visual field loss

Raised intraocular pressure

Question 2

how does glaucoma occur?

Answer 2

poor aqueous production + drainage:
 Anterior chamber angle – angle between cornea + iris, contains trabecular meshwork
 Ciliary body – produces aqueous => post chamber (behind iris) => through pupil => anterior chamber

Question 3

how does aqueous humor outflow?

Answer 3

1. uveoscleral 25%
2. trabecular 75%

Question 4

where does trabecular aq. humor outflow?

Answer 4

drains into the episcleral circulation

Question 5

where does uveoscleral aq. humor outflow?

Answer 5

drains into the choroidal circulation

Question 6

describe the intraocular pressure (IOP)

Answer 6

balance between inflow and outflow of aqueous humor

Question 7

what is the ideal IOP?

Answer 7

11-21 mmHg

Question 8

what IOP indicated high risk glaucoma?

Answer 8

21 mmHg

Question 9

what can cause IOP fluctuations

Answer 9

1. time of day
2. heartbeat
3. blood pressure
4. respiration

Question 10

what are the different types of glaucoma?

Answer 10

1. primary open angle glaucoma
2. primary angle closure glaucoma
3. secondary open angle glaucoma
4. secondary angle closure glaucoma

Question 11

describe primary open angle glaucoma

Answer 11

most common

abnormal resistance of aqueous outflow causing high pressure induced ischemia of optic nerve reducing axoplasmic flow

Question 12

primary open angle glaucoma risk factors

Answer 12

smoking
diabetes
hypertension
high cholesterol
short-sighted

Question 13

mechanism of action of primary open angle glaucoma

Answer 13

acute/chronic
sudden raise in IOP caused by …
1. narrow drainage angle between the cornea and iris
2. fluid cannot exit through trabecular meshwork/ schlemm’s canal

Question 14

describe secondary open angle glaucoma

Answer 14

blockage of trabecular meshwork
e.g. cells/proteins, blood, tumour cells, corticosteroids

Question 15

describe secondary closed angle glaucoma

Answer 15

narrowing /closure of angle
e.g. due to tumour pushing iris/lens forward, new blood vessels, forming fibrous tissue = restricting drainage

Question 16

clinical features of glaucoma

Answer 16

enlarged cup with little neuroretinal ring

Question 17

what is the treatment of glaucoma

Answer 17

1. eye drops/topical
2. systemic
3. laser
4. surgery

Question 18

describe glaucoma eye drops/topical treatment

Answer 18

1. prostaglandin analogues
2. beta-blockers
3. carbonic anhydrases inhibitors
4. sympathomimetics
5. miotics

Question 19

describe glaucoma systemic treatment

Answer 19

1. carbonic anhydrase inhibitors
2. osmotics

Question 20

what is the mechanism of action of prostaglandin analogues

Answer 20

increase uveoscleral outflow to increase drainage and decrease IOP

Question 21

what are the side effects of prostaglandin analogues

Answer 21

1. red eye
2. pigmentation - iris/skin/lash thickening/lengthening

Question 22

name examples of prostaglandin analogues

Answer 22

latanoprost
bimatoprost
travoprost

Question 23

what is the prostaglandin analogues indication

Answer 23

ocular hypertension/glaucoma for the treatment of open angle glaucoma

Question 24

what is the mechanism of action of beta blockers eye drops

Answer 24

reduce aqueous production in the ciliary body

Question 25

what are the contraindications of beta blocker eye drops

Answer 25

asthma COPD heart block bradycardia heart failure

Question 26

what are side effects of beta blocker eye drops

Answer 26

1. allergic conjunctivitis 2. bronchospasm 3. CV: bradycardia/ heart block/ hypotension 4. lethargy 5. glucose intolerance 6. impotence

Question 27

what are examples of beta blocker eye drops

Answer 27

timolol levobunolol

Question 28

what is the mechanism of action of carbonic anhydrase inhibitor

Answer 28

decrease aqueous humour production in ciliary body

Question 29

what are the contraindications of carbonic anhydrase inhibitors

Answer 29

1. sulphonamide sensitivity 2. liver failure (acetazolamide) 3. renal failure (acetazolamide)

Question 30

what are the side effects of carbonic anhydrase inhibitors

Answer 30

1. topical burning/ watery eyes 2. allergic conjunctivitis 3. systemic: - lethargy/depression - metallic taste - metabolic: hypokalaemia - blood dyscrasia

Question 31

what the examples of carbonic anhydrase inhibitors

Answer 31

topical: - dorzolamide - brinzolamide systemic: - acetazolamide (IV/PO)

Question 32

name acetazolamide interactions

Answer 32

thiazide diuretics - profound hypokalaemia

Question 33

name the mechanism of action of alpha-2 agonists

Answer 33

1. decrease aqueous production 2. increase uveoscleral outflow

Question 34

name side effects of alpha-2 agonists

Answer 34

1. allergic conjunctivitis 2. systemic - bradycardia/ hypotension - insomnia/irritability - GI disturbances

Question 35

name which glaucoma drug at high risk of allergic conjunctivitis

Answer 35

alpha-2 agonists

Question 36

name examples of alpha-2 agonists

Answer 36

brimonidine apraclonidine

Question 37

what are the MOA of apraclonidine

Answer 37

temporary lowering IOP causing increase side effects e.g. allergic conjunctivitis and red eye

Question 38

what is the mechanism of action of miotic

Answer 38

1. contraction of ciliary muscle = opens trabecular meshwork = increasing trabecular outflow 2. iris constriction may pull the iris away from angle

Question 39

what are the side effects of miotics

Answer 39

1. sweating/salivation 2. nausea 3. headache 4. bradycardia

Question 40

name examples of miotics

Answer 40

pilocarpine

Question 41

what is the mechanism of action of osmotics

Answer 41

water drawn out of vitreous into blood by gradient = decreasing vitreous volume = lowering IOP

Question 42

name side effects of osmotics

Answer 42

cardiovascular/ fluid overload urinary retention

Question 43

name contraindications of osmotics

Answer 43

cardiac disease/ heart failure

Question 44

name examples of osmotics

Answer 44

IV mannitol oral glycerol