Glaucoma

Question 1

What is glaucoma?

Answer 1

Optic nerve damage that is caused by a significant rise in intraocular pressure

Question 2

What are the 2 types of glaucoma?

Answer 2

• Open angle glaucoma
• Acute angle closure glaucoma (closed angle)

Question 3

Normal physiology
1) What is the anterior and posterior chamber of the eye filled with?
2) This ‘filing’ is produced by what?
3) The ‘filling’ flows through the anterior chamber and then into what?
4) It then flows into a canal - what is this canal called?
5) How is normal intraocular pressure generated?

Answer 3

1) Aqueous humour
2) Ciliary body
3) Trabecular meshwork
4) Canal of Schlemm
6) Resistance to flow through the trabecular meshwork into the canal of Schlemm

Question 4

Pathophysiology (1)
1) What is the pathophysiology in open angle glaucoma?
2) What is the pathophysiology in acute angle-closure glaucoma?
3) Which type is considered an ophthalmological emergency?

Answer 4

1) Gradual increase in resistance through the trabecular meshwork results in an increase in ICP
2) The iris bulges forward and seals off the trabecular meshwork from the anterior chamber preventing aqueous humour from being able to drain away
3) Acute angle-closure glaucoma

Question 5

Pathophysiology (2)
1) Increased pressure in the eye causes what to happen to the optic disk?
2) In the centre of a normal optic disc is the optic cup. When there is raised intraocular pressure, does the optic cup increase or decrease in size?
3) An optic cup of what ratio of the size of the optic disc is considered abnormal?

Answer 5

1) Causes cupping
2) Increase
3) Greater than 0.5 the size of the optic disc

Question 6

Open angle glaucoma (1)
1) Name 2 risk factors
2) What is affected first - central or peripheral vision?
3) Name 2 things that open angle glaucoma can present with the gradual onset of
4) What is the most commonly used machine for estimating intraocular pressure?
5) What is the gold standard for investigating intraocular pressure
6) As well as the above investigation, name another investigation that can be used in the diagnosis of open angle glaucoma

Answer 6

1) Increasing age, family history, black ethnic origin, nearsightedness (myopia)
2) Peripheral
3) Fluctuating pain, headaches, blurred vision
4) Non-contact tonometry
5) Goldmann applanation tonometry
6) Fundoscopy, visual field assessment

Question 7

Open angle glaucoma (2)
1) What medication is 1st line for the management of open angle glaucoma?
2) What type of drug is this
3) How does this drug work?
4) Name 2 side effects of this drug
5) Name 2 other groups of drugs that may be used, give an example of the group, and how do they work

Answer 7

1) Latanoprost eye drops
2) Prostaglandin analogue
3) Increase uveoscleral outflow
4) Eyelash growth, eyelid pigmentation and iris pigmentation
5) Beta-blockers i.e. timolol. They reduce the production of aqueous humour. Carbonic anhydrase inhibitors i.e. dorzolamide. They reduce the production of aqueous humour. Sympathomimetics i.e. brimonidine. They reduce the production of aqueous fluid and increase uveoscleral outflow

Question 8

Acute angle closure glaucoma (1)
1) Name 3 risk factors
2) Name 2 ways patients may present
3) Name 2 examination findings

Answer 8

1) Increasing age, female sex, family history,
Chinese and East Asian ethnic origin, shallow anterior chamber, medication i.e. adrenergic and anticholinergic medications, and tricyclic antidepressants (cholinergic effect)
2) Patient appears very unwell, severely painful red eye, blurred vision, halos around lights, associated headache, nausea and vomiting
3) Red-eye, teary, hazy cornea, decreased visual acuity, dilatation of the affected pupil, fixed pupil size, firm eyeball on palpation

Question 9

Acute angle closure glaucoma (2)
1) What are the 2 drugs given initially, what kind of drugs are they, and how do they work?
2) Name 1 other medication that might be needed in the initial management
3) Name 2 drug groups that may be used in the management of acute angle closure glaucoma in secondary care
4) What procedure is usually required as definitive treatment for acute angle closure glaucoma, and what does this involve?

Answer 9

1) Pilocarpine - muscarinic agonist - causes pupil constriction + ciliary muscle contraction which causes the pathway for the flow of aqueous humour into the trabecular meshwork to open up. Acetazolamide - carbonic anhydrase inhibitor - reduces production of aqueous humour.
2) Antiemetic, analgesic
3) Beta blockers (timolol), carbonic anhydrase inhibitors (dorzolamide), sympathomimetic (brimonidine), hyperosmotic agents (mannitol, glycerol)
4) Laser iridotomy - using a laser to make a hole in the iris to allow the aqueous humour to flow from the posterior chamber into the anterior chamber. This relieves the pressure that was pushing the iris against the cornea and allows the humour the drain