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Ophthalmology > Glaucoma > Flashcards

Flashcards in Glaucoma Deck (23)
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1
Q

What is the definition of glaucoma?

A

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

2
Q

What are the two categories of glaucoma?

A

Open angle and closed angles

3
Q

Which type of glaucoma is a medical emergency?

A

Closed angle or acute glaucoma

4
Q

What proportion of glaucoma is open angle?

A

80%

5
Q

What are the major risk factors for gluacoma? 4

A

Age, Fam Hx, race, thin corneas

6
Q

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

A

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

7
Q

What is the most accurate way to measure intraocular pressure?

A

Golmans applanation tonometry

8
Q

What is the range for normal intraocular pressure?

A

10-20 mmHg

9
Q

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

A

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

10
Q

What is formal visual field testing called?

A

automated perimetry

11
Q

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

A

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

12
Q

What is the medical treatment for open-angle glaucoma?

A

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

13
Q

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

A

timolol

14
Q

Give an example of prostaglandin analogue used in glaucoma treatment

A

latanoprost

15
Q

How topical beta-blockers treat glaucoma?

A

reduce the amount aqueous humour produced

16
Q

how do prostaglandin analogues treat glaucoma?

A

increased the amount of aqueous humour that is absorbed

17
Q

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

A

Brinzolamide reduced the amount of humour produced

18
Q

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

A

trabeculectomy

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

19
Q

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

A

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.

20
Q

How do patients with closed angle glaucoma present?

A

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

21
Q

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

A

Gonioscopy where there is a mirror in a lens

22
Q

What is the treatment for Acute glaucoma?

A

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.

23
Q

What is the surgery used to treat acute glaucoma?

A

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