Glaucoma

Question 1

What is glaucoma

Answer 1

group of eye diseases resulting in damage to the optic nerve

Question 2

What is the most common type of glaucoma?

Answer 2

open angle

Question 3

Explain the pathophysiology behind open angle glaucoma

Answer 3

Aqueous humour, created in the ciliary body, passes through the pupil into the small area between the iris and the cornea, called the anterior chamber. The fluid then flows into the periphery of the chamber known as the anterior chamber angle. This angle is where the fluid travels through the trabecular meshwork and into blood vessels. Open-angle glaucoma is characterised by an anatomically open angle but with an obstructed and slowed drainage system outflow. The mechanism of blockage is unclear. A rise in increased intra-ocular pressure results, characterised by retinal ganglion cell damage, then peripheral vision loss in early disease and central vision loss in late disease

Question 4

What are the RFs for open angle glaucoma?

Answer 4

Intra-ocular pressure >21mmhg
age >50
FHx
Black ethnicity

Question 5

How does POAG present?

Answer 5

can be insidious!! - may be incidental finding

• peripheral visual field loss - nasal scotomas progress to tunnel vision
• decreased visual acuity
• optic disc cupping

Question 6

What are diagnostic features of POAG?

Answer 6

1. optic disc cupping: cup-to-disc ratio >0.7 - loss of disc substance makes optic cup widen and deepen
2. Notching of optic nerve cup
3. Raised intrauocular pressure
4. Loss of nerve fibre layer

Question 7

What is a scotoma?

Answer 7

area of lost or depressed vision surrounded by an area of less depressed or normal vision

Question 8

What investigations would u do in POAG

Answer 8

1. Tonomety - measure IOP
2. Ophthalmoscopy - visualise retina + optic disc
3. Slit lamp examination
   4.

Question 9

What is normal cup:disc ratio?

Answer 9

0.4-0.7

Question 10

What is the treatment of POAG?

Answer 10

1. Prostaglandin analogue eyedrops - latanoprost - increase outflow of AH
2. BB - timolol - decrease production of AH
   Trabeculoplasty to open trabecular meshwork

Question 11

When are BBs avoided as rx?

Answer 11

asthmatics

patients w heart block

Question 12

What is treatment of POAG if medical measures fail?

Answer 12

laser or surgical rx

Question 13

Why is it important to reassess pts w POAG?

Answer 13

to exclude progression and visual field loss

Question 14

what is angle closure glaucoma?

Answer 14

there is reversible or adhesion closure of the anterior chamber angle - raised IOP

Question 15

What are the RFs for acute angle closure glaucoma?

Answer 15

hypermetropia - long sightedness
pupillary dilatation
lens growth associated w age

Question 16

How does AACG present?

Answer 16

1. Severe pain - ocular/headache
2. Reduced visual acuity
3. Halos around lights
4. N+V
5. Red eye
6. Fixed dilated pupil
7. Corneal oedema - dull or hazy cornea

Question 17

What is the pharmacological management of AACG?

Answer 17

1. Acetazolamide + BB (timolol)
2. Pilocarpine
3. Mannitol

Question 18

What is the surgical management of AACG? when is it indicated?

Answer 18

Peripheral iridectomy - piece of iris removed in both eyes to allow AH to flow
Once IOP is controlled