Glaucoma (General)

Question 1

Anatomy : Chambers of the Eye (3).

Answer 1

Anterior –> Posterior :

1. Anterior Chamber (Between Cornea and Iris).
2. Posterior Chamber (Beween Iris and Lens).
3. Vitreous Chamber (Behind Lens).

1 + 2 are filled with Aqueous Humour (Supply Nutrients to Cornea).
3 is filled with Vitreous Humour (Provide Shape and Structure).

Question 2

Aqueous Humour Physiology (6).

Answer 2

1. Produced by Ciliary Body.
2. Flows from Ciliary Body between Lens and Iris.
3. Flows from Posterior Chamber into Anterior Chamber.
4. Flows through the Trabecular Meshwork.
5. Exits via the Canal of Schlemm.
6. Enters General Circulation.

Question 3

What is the normal range of intraocular pressure?

Answer 3

Between 10-21 mmHg.

Question 4

How is Intraocular Pressure created and maintained?

Answer 4

The pressure is created and maintained by the resistance to flow through the trabecular meshwork into the canal of Schlemm.

Question 5

Investigations of Glaucoma (3).

Answer 5

1. Non-Contact Tonometry.
2. Goldmann Applanation Tonometry.
3. Fundoscopy - Optic Disc Cupping and Optic Nerve Health.

Question 6

What is Non-Contact Tonometry?

Answer 6

A technique used by Opticians to estimate IOP where a ‘puff of air’ is shot at the cornea to measure the corneal response) - screening purposes.

Question 7

What is Goldmann Applanation Tonometry?

Answer 7

The Gold Standard technique to measure IOP - a special device is mounted on a slit lamp to make contact with the cornea and apply different pressure to the front of the cornea to measure IOP accurately.

Question 8

What is Glaucoma?

Answer 8

Optic Nerve Damage caused by a significant rise in intraocular pressure (caused by a blockage in aqueous humour drainage from the eye).

Question 9

What are the 2 types of Glaucoma?

Answer 9

Open-Angle Glaucoma : Chronic Glaucoma.

Closed-Angle Glaucoma : Acute Glaucoma.

Question 10

Example of Prostaglandin Analogue Eye Drops.

Answer 10

Latanoprost.

Question 11

Mechanism of Action of Prostaglandin Analogue Eye Drops.

Answer 11

Increase Uveoscleral Outflow.

Question 12

Adverse Effects of Prostaglandin Analogue Eye Drops (3).

Answer 12

1. Eyelash Growth.
2. Eyelid Pigmentation.
3. Iris Pigmentation (Browning).

Question 13

Example of B-Blocker Eye Drops.

Answer 13

Timolol.

Question 14

Mechanism of Action of B-Blocker Eye Drops.

Answer 14

Reduce production of aqueous humour.

Question 15

Contraindications of B-Blocker Eye Drops (2).

Answer 15

1. Asthma.

2. Heart Block.

Question 16

Examples of Carbonic Anhydrase Inhibitor Eye Drops (2).

Answer 16

1. Acetazolamide.

2. Dorzolamide.

Question 17

Mechanism of Action of Carbonic Anhydrase Inhibitor Eye Drops.

Answer 17

Reduce production of aqueous humour.

Question 18

Adverse Effect of Carbonic Anhydrase Inhibitor Eye Drops.

Answer 18

Systemic Absorption : Sulphonamide-Like Reaction.

Question 19

Mechanism of Action of Pilocarpine Eye Drops (3).

Answer 19

1. Miotic Agent (acts on Muscarinic receptors in Iris Sphincter Muscles to cause pupil constriction).
2. It also causes ciliary muscle contraction.
3. Both effects cause a pathway for the flow of aqueous humour from the ciliary body around the iris into the trabecular meshwork to open up.

Question 20

Dose of Pilocarpine Eye Drops (2).

Answer 20

2% for Blue Eyes; 4% for Brown Eyes.

Question 21

Examples of Hyperosmotic Agents (2).

Answer 21

1. Mannitol.

2. Glycerol.

Question 22

Mechanism of Action of Hyperosmotic Agents.

Answer 22

Increase Osmotic Gradient between Blood and Fluid in Eye.

Question 23

Examples of Sympathomimetic Eye Drops (2).

Answer 23

1. Brimonidine.

2. Apraclonidine.

Question 24

Mechanism of Action of Sympathomimetic Eye Drops.

Answer 24

Reduce production of aqeuous humour and increase uveoscleral outflow.

Question 25

Contraindications of Sympathomimetic Eye Drops (2).

Answer 25

1. MAO Inhibitor Use.

2. TCA Use.

Question 26

Adverse Effect of Sympathomimetic Eye Drops.

Answer 26

Hyperaemia.