Glaucoma

Question 1

What is glaucoma?

Answer 1

optic nerve damage caused by and increase in intraocular pressure– blockage in aqueous humour trying to escape the eye

Question 2

What are the two types of glaucoma?

Answer 2

open-angle and close-angle

Question 3

What is the normal intraocular pressure?

Answer 3

16 mmHg

Question 4

What is the intraocular pressure from?

Answer 4

resistance to flow through the trabecular meshwork

Question 5

What is the difference between open-angle and closed-angle glaucoma?

Answer 5

open is chronic and closed is acute

Question 6

What are the risk factors for open angle glaucoma?

Answer 6

-age
-family history
-black ethnic origin
-near sightedness (myopia)

Question 7

What is the presentiaton of open-angle?

Answer 7

-asymptomatic– routine screening by optometrist
-gradual loss of peripheral vision (tunnel)
-fluctuating pain
-headaches
-blurred vision
-halos surrounding lights (worse at night)

Question 8

What is the gold standard for measuring intraocular pressure?

Answer 8

Goldmann applanation tonometry

Question 9

What is a non-contact tonometry?

Answer 9

-measures pressure
-uses the puff of air

Question 10

What is the first line treatment for open angle glaucoma?

Answer 10

prostaglandin analogues– latanoprost
-they increase uveoscleral outflow

SE: increase in lash growth and a browning of the iris

Question 11

What is closed angle glaucoma?

Answer 11

-when the iris bulges forward and blocks the trabecular meshwork– fluid can’t drain

This is an EMERGENCY and needs treatment or will result in a loss of vision

Question 12

What are the risk factors for closed angle glaucoma?

Answer 12

-increased age
-female
-family history
-Chinese/East Asian ethnic origin
-shallow anterior chamber

Question 13

What medications are a risk factor for closed angle glaucoma?

Answer 13

-adrenergic medications
-anticholinergic medications
-tricyclic antidepressants

Question 14

What is the presentation of closed angle glaucoma?

Answer 14

-appear unwell
-blurred vision
-severely painful red eye
-halos around lights
-associated headache, nausea and vomiting
-hazy cornea
-decreased vision
-dilated, fixed size pupil
-eyeball is firm and hard

Question 15

Management of closed angle glaucoma

Answer 15

-refer for same day assessment by opthalmology
-lie on back
-pilocarpine eye drops
-acetazolamide orally
-analgesia
-antiemetic

Question 16

How does Pilocarpine eye drops help with closed angle glaucoma?

Answer 16

-causes constriction of the pupil
-ciliary muscle contraction
-this results in drainage of the fluid

Question 17

What is aqueous humor?

Answer 17

transparent watery fluid that nourishes lens and cornea

-produced by ciliary body
-flows into posterior chamber, through pupil, and into anterior cornea
-drains into scleral venous sinus and is returned to blood
-normally, completely replaced about every 90 minutes

Question 18

What intraocular pressure (IOP) is considered abnormal? Which requires treatment?

Answer 18

> 21 is abnormal and >30 requires treatment

Question 19

How is the first line treatment different for open and closed?

Answer 19

first line for open is pharmacological treatment and for closed it is laser surgery (because it’s an emergency)

Question 20

What screening is done to detect glaucoma?

Answer 20

-measure IOP
-measure drainage angle
-examine optic nerve
-visual field test

Question 21

What drug classes are used for lowering IOP to treat glaucoma?

Answer 21

1) prostaglandin analogues
2) beta adrenergic antagonists
3) alpha2 adrenergic agonists
4) carbonic anhydrase inhibitors
5) cholinergic agonists

prescribed in this order (first-line is 1)

Question 22

What does punctual compression do?

Answer 22

delays drainage of drug into the lacrimal duct by pressing the medial eye-nose corner

minimizes absorption of drug into the bloodstream and systemic side effects

Question 23

What are the side effects of latanoprost?

Answer 23

sensation of foreign body in eye, burning on instillation, iris discolouration, red eyes and thickening/darkening of eyelashes