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The Patient (Y3-1) > Glaucoma > Flashcards

Flashcards in Glaucoma Deck (27)
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1

What are some fo the risk factors for glaucoma?

High intraocular pressure (>21 mmHg)
Family history
Systemic hypertension
CVD
Migraine
Previous ocular disease

2

What are the two types of glaucoma?

Open angle
Closed angle

3

Which type of glaucoma is primarily treated with drugs?

Open angle

4

What causes glaucoma?

An imbalance between the production of aqueous humour and drainage of aqueous humour

5

Where is aqueous humour produced?

Ciliary epithelium

6

Normally in the eye, why is there continuous flow and drainage of aqueous?

Because the pressure inside the eye is greater than the pressure outside in the episcleral vein and Schlemm's canal

7

What are the two pathways in which aqueous humour is drained?

Trabecular meshwork - main
Uveoscleral flow

8

Why is there resistance to flow in the uveoscleral pathway?

Because cells are tightly packed within tissues and therefore it is harder for humour to drain through

9

What are the drug classes for treatment options for glaucoma?

Prostaglandin + prostamide analogues
B-blockers
Carbonic anhydrase inhibitors
A2-adrenoreceptor agonists
Parasympathomimetics

10

Where are FP receptors located?

Few in the trabecular meshwork
Iris sphincter
Ciliary body and muscle

11

Where are a2 receptors found in the eye?

Ciliary, conjunctival and corneal epithelial cells

12

Which drug classes reduce IOP by increasing uveoscleral outflow?

Prostaglandin and prostamide analogues

13

How do prostamide and prostaglandin analogues work?

They reduce resistance to uveoscleral outflow by remodelling the extracellular matrix. They do this by increasing matrix metalloproteinases which degrade collagen and the extracellular matrix, reducing the resistance of the sclera and ciliary muscle

14

What is the mechanism of action of timolol?

Decreases ion concentration, decreases fluid along gradient and so decreases aqueous humour production

15

Name a CAI used in the treatment of glaucoma

Acetazolamide - systemic CAI
Brinzolamide and dorzolamide - topical CAI

16

Which two drug classes are similar in the moa in terms of decreasing ion concentration, decreasing fluid along the gradient and reducing aqueous humour production?

B-blockers and CAIs

17

Which drug is used post-operatively in laser eye surgery?

Apraclonidine

18

Why is the long-term use of a2 adrenoreceptor agonists not sufficient in the treatment of glaucoma?

Because they densensitise quickly

19

What are some advantages of treatment using a2 adrenoreceptors?

Little effect on CV system
No vasoconstriction
No mydriasis

20

Name a a2 adrenoreceptor agonist

Brimonidine
Apraclonidine

21

Which class of drugs causes CV side effects, bronchial side effects and diabetic side effects?

B-blockers

22

How do CAIs work?

inhibiting carbonic anhydrase which is needed in the production of bicarbonate. Bicarbonate is needed for aqueous secretion so by blocking this, aqueous humour production is reduced and IOP is lowered

23

Which is the least effective drug in lowering IOP?

Pilocarpine

24

How does pilocarpine work?

It mimics the effects of acetylcholine in the parasympathetic system
It contracts ciliary muscle
It pulls scleral spur
Opens the trabecular meshwork and so increases trabecular outflow, reducing IOP

25

What are the benefits of fixed dose combinations?

Reduced cost for patient
Reduced cost of treatment
Patient compliance
Reduced exposure to preservatives

26

Which drug is used in emergencies only, where IOP is highly elevated and why?

Acetazolamide - due to severe side effects

27

How have topical CAIs been developed from acetazolamide?

Acetazolamide is a sulphonamide derivative - it has been modified to give better lipid solubility and therefore reduced S/Es. Topical CAIs also have increased selectivity for CAII enzyme in ciliary epithelium