Pharm 2013.09.05 Glaucoma

Question 1

What is Glaucoma?

Answer 1

Production of aqueous fluid exceeds drainage of aqueous fluid
This increases intraoccular pressure
Can lead to death of retinal ganglion cells, optic nerve damage, impaired vision, blindness

Question 2

What are the key features of closed angle glaucoma?

Answer 2

10% of glucoma
Acute episodes of intense eye pain, visual disturbances, headache
Reduced angle between iris and cornea
Iris partially obstructs trabecular meshwork and fluid drainage
During pupil dilation, iris is “thicker”, can produce acute severe blockage of drainage and rapid increase in pressure

Question 3

What are the key features of open angle glaucoma?

Answer 3

90% of glaucoma
Due to either overproduction of aqueous fluid or impairment of drainage through trabecular meshwork
Slow chronic condition
Typically asymptomatic (gradual onset of vision loss)
“silent thief of sight”

Question 4

What is the Rx for closed angle glaucoma?

What is administration route?

Answer 4

Pilocarpine

eye drops or contacts

Question 5

What does Pilocarpine do?

Answer 5

1) Stimulates Muscarinic receptors on ciliary sphincter muscle
2) Constriction of ciliary muscle increases tension on trabecular meshwork → “opens up passages” → increases outflow
3) Pupil constriction (miosis) “thins the iris” → removes obstruction
4) Enables aqueous drainage

Question 6

Explain the receptors that trigger dilation and constrition of the iris and ciliary muscles
Iris radial muscle?
Iris circular muscle?
Ciliary muscle?

Answer 6

Iris Radial: pupil dilation (mydriasis) alpha 1 receptor sympa
Iris Circular: constriction M3 Muscarinic Para
Ciliary muscle relaxes for far vision Beta 2 receptor sympa
Ciliary muscle constricticts M3Mscarinic receptor Para (?)

Question 7

What is the angle of the ciliary muscle?
What angle does it control?
What happens when relaxed?
What happens when contracted?

Answer 7

1) Controls the angel of refraction of the lens
2) When relaxed, it places tension on the lens to flatten it and accommodate for far vision
* * Cycloplegia – extreme drug induced relaxation
3) When contracted, it decreases tension on the lens which rounds up of its own elasticity to accommodate for near vision
* * Cilospasm (cyclospasm) – extreme drug induced constriction