glaucoma

Question 1

what is gonioscopy ?

Answer 1

used to evaluate eye’s drainage angle
anterior chambre angle

Question 2

what is the pathology behind glaucoma ?

Answer 2

chronic progressive optic neuropathy resulting in progressive irreversible vision loss
|
increased intraocular pressure
|
loss of retinal ganglion cells causing disc cupping
|
associated visual field loss

Question 3

what are the main subtypes of glaucoma ?

Answer 3

open angle glaucoma
angle closure glaucoma
secondary glaucoma
congenital glaucoma

Question 4

what is normal tension glaucoma ?

Answer 4

a subtype of primary open angle glaucoma

Question 5

where is the aqueous humor produced ?

Answer 5

ciliary bodies, specifically by pars plicata

Question 6

what is the normal pathway of the aqueous humor ?

Answer 6

1.after being secreted by the ciliary bodies
2.passes from the posterior chamber to the anterior chamber
3. in front of the lens , via the pupil
4. drained at the trabecular meshwork at the angle of anterior chamber
5. passes through the canal of schelmn

Question 7

what is the course of open angle glaucoma ?

Answer 7

chronic and slowly progressive

Question 8

what is the presentation of open angle glaucoma ?

Answer 8

silent condition
usually asymptomatic

Question 9

what are the risk factors associated with open angle glaucoma ?

Answer 9

increased intra-ocular pressure
aging
positive family history ( 1st degree relatives)
afro-caribbeans
central corneal thickness less than 555
high myopia, diabetes or hypeeertension
eye injury or surgery

Question 10

what examinations are to be performed on a glaucoma patient ?

Answer 10

fundus examination
tonometry
gonioscopy
humphry visual field

Question 11

what is the management stratergy for open angle glaucoma ?

Answer 11

halt optic nerve damage by reducing IOP

Question 12

what are the treatment options regarding open angle gluacoma ?

Answer 12

medications
laser
filtration surgery

Question 13

what are the different medications that can be usedd for open angle glaucoma ?

Answer 13

prostaglandin analogue
beta blocker
selective a2 receptor agonist
carbonic anhydrase inhibitor

Question 14

why are prostaglandin analogues used ?

Answer 14

first line treatment
to increase uveoscleral outflow

Question 15

which prostaglandins are used ?

Answer 15

latanoprost and bimatoprost

Question 16

what are the side effects of using prostaglandin analogues ?

Answer 16

pigmentation
increase eyelash length
stinging sensation

Question 17

what are the contraindications to using beta blockers ?

Answer 17

timolol
in asthmatics, COPD and heart block

Question 18

what is the mechanism of action that occurs when using beta blockers in glaucoma ?

Answer 18

reduction on aqueous humor production

Question 19

what selective a2 receptor agonist is used ?

Answer 19

brimonidine

Question 20

what are the side effects associated with selective a2 receptor agonists ?

Answer 20

lethargy
dry eyes
dry mouth
allergy

Question 21

what is the mechanims of action associated with carbonic anhydrase inhibiitors ?

Answer 21

reduced production of aqueous humor
dorzolamide
brinzolamide

Question 22

why is high myopia associated with an increased chance of glaucoma ?

Answer 22

due to the increased axial length which lead to tilting of the optic disc and hence the optic nerve putting it at a higher risk of damage

Question 23

what surgeries are performed for open angle glaucoma ?

Answer 23

1. trabeculoplasty to provide an alternative pathway for the passage of the aqueous humor
2. trabeculectomy to insert a shunt

Question 24

what are the risk factors associated with angle closure gluacoma ?

Answer 24

hypermetropia
cataracts
mydriatics
abnormal iris configuration
asian ethnicity
elderly females

Question 25

what are mydriatics ?

Answer 25

eye drops that dilate the pupil

Question 26

how does an abnormal iris configuration cause a closed angle ?

Answer 26

1.plateau iris syndrome , on dilatation the iris folds into the angle and blocks the trabecular meshwork
2.. pupillary block - iris adhered to the lens blocking the flow of the aqueous humor ( posterior synechiae)

Question 27

what are the symptoms of angle closure gluacoma ?

Answer 27

sudden onset of pain
blurred vision
colored halos around light
frontal headache
nausea and vomiting

Question 28

what are the signs associated with closed angle glaucoma ?

Answer 28

IOP more than 40 mmgh
corneal oedema
limbal hyperemia
fixed mid-dilated pupil
shallow anterior chamber
closed angle on gonioscopy

Question 29

what is the normal IOP ?

Answer 29

11-21 mmhg

Question 30

what is the systemic treatment for angle closure glaucoma ?

Answer 30

refer to opthalmologist - medical emergency
1. IV Carbonic anhydrase inhibitor (CAI) Acetazolamide 500mgs.
2. PO Acetazolamide 500mgs
3. Anti-emetics
4. IV mannitol or Oral glycerol

Question 31

what is the definitive treatment for angle closure glaucoma ?

Answer 31

peripheral laser iridotomy
lens extraction (to open the angle and deepen the AC)
surgical trabeculectomy or iridectomy

Question 32

what are the three methods of drainage of aqueous humor in the eye ?

Answer 32

trabecular outflow ( 90% )
uvoscleral drainage
iris

Question 33

what is the key modifiable factor in glaucoma ?

Answer 33

intra-ocular pressure

Question 34

what is the normal cup:disc ratio ?

Answer 34

0.3

Question 35

what is the cup: dic ration in glaucoma ?

Answer 35

more than 0.7 is usually indicative of glaucoma

Question 36

what is the cup and what is the disc ?

Answer 36

cup : head of optic nerve
dic : neuro-retinal rim