Glaucoma

Question 1

What is the definition of glaucoma?

Answer 1

A disease where the optic nerve dies composed of many aeitologies including vascular, biochemical and intraocular pressure

Question 2

What are the two categories of glaucoma?

Answer 2

Open angle and closed angles

Question 3

Which type of glaucoma is a medical emergency?

Answer 3

Closed angle or acute glaucoma

Question 4

What proportion of glaucoma is open angle?

Answer 4

80%

Question 5

What are the major risk factors for gluacoma? 4

Answer 5

Age, Fam Hx, race, thin corneas

Question 6

What are the 3 examination finding which will usually be found in open angle glaucoma?

Answer 6

Elevated eye pressures
Disc changes (cup:disc >.5)
Repeatable visual field loss

Question 7

What is the most accurate way to measure intraocular pressure?

Answer 7

Golmans applanation tonometry

Question 8

What is the range for normal intraocular pressure?

Answer 8

10-20 mmHg

Question 9

When measuring the cup:disc ration on fundoscopy what rule can be used to assess whether the cup is normal?

Answer 9

The cup should make up about one third of disc. If the cup is higher than .5 of the disc then this is indicative of glaucoma. The ISNT rule also applies - this means that The space between the edge of the disc and the edge of the cup should decrease in size from inferior, superior, nasal and then temporal

Question 10

What is formal visual field testing called?

Answer 10

automated perimetry

Question 11

What is the visual loss pattern in open-angle glaucoma?

Answer 11

Central vision is spared meaning that people often don’t notice the visual loss until it is too late

Question 12

What is the medical treatment for open-angle glaucoma?

Answer 12

Topical beta-blockers
Topical Carbonic Anhydrase inhibitors
Alpha-agonists
Prostaglandin analogues

Question 13

Give an example of a topical beta-blocker used in glaucoma treatment

Answer 13

timolol

Question 14

Give an example of prostaglandin analogue used in glaucoma treatment

Answer 14

latanoprost

Question 15

How topical beta-blockers treat glaucoma?

Answer 15

reduce the amount aqueous humour produced

Question 16

how do prostaglandin analogues treat glaucoma?

Answer 16

increased the amount of aqueous humour that is absorbed

Question 17

Give an example of a Carbonic anhydrase inhibitor used in glaucoma and its mechanism of action

Answer 17

Brinzolamide reduced the amount of humour produced

Question 18

What is the name of the surgery that can be done to treat open-angle glauscoma?

Answer 18

trabeculectomy

This involves making a bleb in the superior limbus which gives and alternative pathway for the humour to drain

Question 19

What is the most common mechanism for acute glaucoma to occur?

Answer 19

pupillary block where the lens plasters against the back of the iris which blocks all aqueous flow through the pupil. This pushes the iris anterior against the interior surface if the cornea, this blocks drainage of all aqueous by the trabecular meshwork and damages the retina.

Question 20

How do patients with closed angle glaucoma present?

Answer 20

Extremely red and painful eye.
Nausea + vomiting.
Pressures can be above 60 mmHg.

Question 21

What technique can be used to visualise the irido-corneal angle?

Answer 21

Gonioscopy where there is a mirror in a lens

Question 22

What is the treatment for Acute glaucoma?

Answer 22

You would prescribe anything available to reduce the IOP including all the treatments of open-angle glaucoma (timbale, CAIs, Alpha-agonists, prostaglandins) but ultimately these patients will need surgery. IV mannitol can be used.

Question 23

What is the surgery used to treat acute glaucoma?

Answer 23

Laser iridotomy where a hole is burnt into the the iris relieving the pressure gradient