Glaucoma

Question 1

what is glaucoma?

Answer 1

It is a group of ocular disorders characterised by increased intraocular pressure

Question 2

What are the two types of glaucoma?

Answer 2

• Open angle

- Closed angle glaucoma

Question 3

Describe open and closed angle glaucoma/

Answer 3

• Open angle - occur in more than 70% of the glaucoma cases
• chronic condition that has no symptoms until visual impairemnts start to occur

Closed angle - More severe, can lead to nerve damage
- usually diagnosed during surgery

Question 4

Impairement in aqueous humour outflow can result in an increase in intraocular presssure. TRUE OR FALSE?

Answer 4

TRUE

Question 5

What can occur when IOP is increased?

Answer 5

• Leads to nerve damage
• Loss of peripheral vision
• and eventually blindness

Question 6

How is aqueuous humour produced and drained?

Answer 6

• Aqueous humor is produced by the non-pigmented ciliray body (cilia)
• This then flows behind the lens and throught the pupil via the trabecular mesh work to be drained out via the canal of schlemm

Question 7

What are the two routes of aqueous humor drainage and how much in terms of percentage is drained from each?

Answer 7

• Via the canal of schlemm (conventional - 90%)

- Via Uveoscleral outflow - this allows for drainage without passign through the trabecular network (aletrantive 10%)

Question 8

what are the two types of cilia epithilia?

Answer 8

• Darker inner layer - pigmented epthilia

- Outer layer - non-prigmented epithilia

Question 9

How much aqueous humor is produced?

Answer 9

• 3mL of aqueous humor is produced per day with coninus ultrafiltration from aterial blood and active secretion

Question 10

Aqueous humor passes from posterior to anterior chamber via the pupils. TRUE OR FALSE?

Answer 10

TRUE

Question 11

What is the normal IOP?

Answer 11

• 10-20mm Hg - this inceases in glaucoma

Question 12

What is IOP determined by?

Answer 12

• Rate of aquoeus humor production

- rate of aquoeus humor drainage

Question 13

Increased IOP causes damage to the retina and optic nerve. TRUE OR FALSE?

Answer 13

TRUE

Question 14

What occurs in closed angle (angle glaucoma)?

Answer 14

• Iris presses forwards
• Adheres to the trabecular network (closing the angle)
• This prevents outflow of aqueous humor
• Leading to acute but large increase in IOP
• Leads to rapid nerve damage
• Eventually blindness

Question 15

Wat occurs in open angle glaucoma?

Answer 15

• It is most common amongst patients
• Not many structural changes observed
• Angle is usually the same but the outflow of aqueous humor is reduced i.e due to blockage in trabecular meshwork, canal of schlemm or vein draining the eye
• IOP is not as increased compared to cloased angle but can cause nerve damage over time

Question 16

Visual impairement caused prior diagnosis is usually unlikely to be treated/ restored. TRUE OR FALSE?

Answer 16

TRUE

Question 17

The angle in closed between the iris and the cornea. TRUE OR FALSE?

Answer 17

TRUE

Question 18

IOP is increased by altered AH production and outflow . TRUE OR FALSE?

Answer 18

TRUE

Question 19

What are the treatment options for treating open angle glaucoma?

Answer 19

• Increase AH outflow via Prostaglandins via the uveoscelral path
• Decreased AH production by ciliary body with B2 anatagonists, a2 agonists an carboni anhydrase inhibitors

Question 20

What are the treatment options for closed angle glaucoma?

Answer 20

• Managment of Increased IOP by manitol
• Miotics - increase outflow of AH via the trabecular meshwork
• Prostangladins to increase outflow of AH via uvescleral
• Surgery to reduce pressure betweenthe anteror and psoterior chambers

Question 21

Give an example of Prostangladins F2a analgue?

Answer 21

• Latanoprost - increases outfflow through uvescleral pathway
• Better efficacy and fewer systemic side effects

Question 22

Water is osmotically pumped into the aquoes humor via the Na+/K+ ATPase. TRUE OR FLASE?

Answer 22

TRUE

Question 23

Na+ and Cl- balance is restored from stroma via antiports in the pigmented epithlial cells. TRUE OR FLASE?

Answer 23

TRUE

Question 24

The electrochemical balance is maintained by the xports of H+ and HCO3- produced by carbonic anhydrase. TRUE OR FALSE?

Answer 24

TRUE

Question 25

Increased cAMP does not increase AH production. TRUE OR FALSE?

Answer 25

FALSE

Question 26

B-andrenergic activation increases cAMP production. therefore B-andrenergic antagonists will reduce AH production. TRUE OR FLASE?

Answer 26

TRUE

Question 27

A-andrehergic decreases cAMP activation. Therefore A-andrenergic agonist will reduce AH production. TRUE OR FALSE?

Answer 27

TRUE

Question 28

A-andrenergic agonist indirectly reduces AH production by reducing B-adrenergic production. TRUE OR FALSE?

Answer 28

TRUE

Question 29

B- receptors in the eye are primarily B2. true or false?

Answer 29

true

Question 30

B2 receptors regulate AH production by ciliary body and they decrease blood flow to the eye therefore decreasing the fluid available for AH production (e.g timolol). TRUE OR FLASE?

Answer 30

TRUE

Question 31

B antagonists are contradincated with asthma ptients and patients with heart failure. TRUE or FALSE?

Answer 31

TRUE

Question 32

Provide an example of a a2 agonist drug?

Answer 32

Brimonidine

Question 33

How do a2 agonist work (mechanism of action)? | What are the two mechanisms of action?

Answer 33

- pre-synaptic membrane inhibit NA release (Sympathetic Nervous System) - activation of a2 receptors direcrly inhibits the formatio of AH prouction

Question 34

Carbonic anhydrases inhibiotrs are mostly used in open angle glaucoma. TRUE IR FALSE?

Answer 34

TRUE

Question 35

Brinzolamide is most commonly used carbonic anhydrase inhibitors as it is given topically. TRUE OR FALSE?

Answer 35

TRUE

Question 36

Drug interactions with carbonic anhydrase inhibitors with digoxin. TRUE OR FALSE?

Answer 36

TRUE

Question 37

Drugs that cause hypokaleamia are contranidicated in patients receiving digoxin including acetazolamide. TRUE OR FALSE?

Answer 37

TRUE

Question 38

Miotics for closed angle glaucoma opens drainage channels. TRUE OR FALSE?

Answer 38

TRUE

Question 39

Mannitol for closed angle glaucoma reduces fluid secretion into the eye. TRUE OR FALSE?

Answer 39

TRUE