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Opthalmology > Glaucoma > Flashcards

Flashcards in Glaucoma Deck (19):
1

What is glaucoma?
-what is a risk factor?

A group of diseases characterised by progressive optic nerve damage and visual field loss.
Raised intra-ocular pressure is a prominent risk factor

2

What is the pathogenesis of glaucoma?

-Usually blockage to aqueous outflow
-Raised intra-ocular pressure
-Damage and loss of retinal nerve fibres at optic disc
-Visual field loss

3

What are the signs of glaucoma?

Raised intra-ocular pressure
characteristic field defects
Optic disc cupping

4

What is included in the diagnosis and management of glaucoma?

IOP- tonometry
Fields - perimetry
optic nerve/disc - clinical examination

5

What changes to the optic disc is seen in glaucoma?

-increased cupping

-fewer nerves course through optic disc

-Cup: disk ratio > 0.4-0.7

-vertical thinning and notching of neural rim
(Neural rim= space between inner cup and surrounding disc, and normal rims follow ISNT rule)

Haemorrhage at disc

Disc vessels displaced nasally

Optic atrophy – optic disc becomes pale as damage progresses

6

What is the ISNT rule for optic discs

Inferior rim Thickest
Superior rim
Nasal rim
Temporal rim Thinnest

In glaucoma this is lost

7

What is the classic visual field loss in glaucoma?

-Central vision typically SPARED e.g. late stage patients may have 20/20 central vision but peripheral blindness
-Arcuate scotoma

8

For primary open angle glaucoma:
-how does this present?

No symptoms till late
a disease of signs
needs to be screened for
Most detected by optometrist at routine examination

9

What are the risk factors for primary open angle glaucoma?

Age
raised intraocular pressure
Afro-Carribean origin
Family history

10

What is the aim of treatment for primary open angle glaucoma?

Lower IOP to a level that prevents further nerve damage

Target IOP varies between patients

11

What is the first line medical treatment for primary open angle glaucoma?

Prostaglandin analogues (Bimatoprost 300micrograms/mL, every evening)
-increase uveoscleral outflow
-make iris vessels more leaky



Beta blockers (Timoptol, laevobutanol)
-Reduce aqueous secretion
Systemic side effects -reduced by shutting eyes for a few minutes
-Few topical side effects


Carbonic anhydrase inhibitors and systemic drugs (Acetazolamide PO or IV, 0.25-1g daily)
-Very effective at lowering IOP
-BUT systemic side effects – Parasthesia, peri-oral tingling, renal calculi
-Short term use only
-can use topical but local irritation and much less effective (no systemic side effects)

Sympathomimetics (adrenaline, propine, alphagan)
Increase outflow
dilate pupil
local irritation, hyperaemia
cardiovascular side effects
long term use reduces the success of surgery

Parasympathomimetics/ Miotics (Pilocarpine Hydrochloride 0.5%, topical eye drops, up to four applications daily, adrenaline, propine, alphagan)
Increase outflow
few systemic side effects
Many local side effects
pupil constriction - pain, dimming of vision, problems at night

12

What is the usual order of treatment for primary open angle glaucoma

Prostaglandin
B-blocker
Trusopt/alphagan
surgery

13

What surgery is used for primary open angle glaucoma?

Trabeculectomy

14

What are the pros and cons of surgery?

Surgery more effective
Better compliance

But intra-ocular surgery
Increases progression of cataract

15

What can cause secondary open angle glaucoma?

Blood
Uveitis
Lens protein
Pseudo-exfoliation

16

Acute closed angle glaucoma:
-what is this?
-who usually suffers this?

Hypermetropes (long-sighted)
Closure of the angle by iris causes sudden rise in IOP
Disease of symptoms

17

What are the symptoms of acute angle closure glaucoma?

Pain
Nausea + vomiting
Reduced vision
Hazy cornea
Fixed mid-dilated pupil

18

What is the treatment for acute angle closure glaucoma?

Reduce IOP medically
Peripheral iridotomy – surgical or laser


Beta blockers (Timolol 0.5% single dose)



Steroids (Prednisolone 1% one dose every 15 minutes for an hour, followed by hourly doses)



Apraclonidine 0.5-1% single dose



Natural lens: Pilocarpine 1-2% single drop an hour after treatment commenced



No natural lens: Phenylephrine 2.5% single drop



Acetazolamide given IV (500mg over 10 minutes), with further 250mg slow-release tablet after an hour



If no response, systemic hyperosmotics used (glycerol PO 1 gm/kg of 50% solution in lemon juice or mannitol 20% solution IV 1-1.5 gm/kg)



Systemic analgesia



Anti-emetics

19

What is the normal range for intraocular pressure?

10-21