open angle glaucoma

Question 1

define glaucoma

Answer 1

optic nerve damage caused by rise in intraocular pressure

Question 2

what causes a raised intraocular pressure?

Answer 2

blockage by aqueous humour trying to drain from inside eye

Question 3

what is the pathophys of OAG?

Answer 3

gradual increase in resistance to flow to trabecular meshwork eg raised intraocular pressure

Question 4

how does a raised intraocular pressure cause OAG?

Answer 4

increased pressure causes cupping of optic disk - makes it wider and deeper

Question 5

what are RF for OAG?

Answer 5

increased age
family history
black
myopia - nearsighted

Question 6

when can OAG present?

Answer 6

can be symptoms
asymptomatic - picked up on routine check

Question 7

how does symptomatic OAG present initially?

Answer 7

affects peripheral vision - gradual onset of peripheral vision loss (tunnel vision)

Question 8

after tunnel vision, what other symptoms may be seen in OAG?

Answer 8

fluctuating pain
headaches
blurred vision
halos around lights

Question 9

how do you diagnose OAG and why?

Answer 9

goldmann applanation: intraocular pressure
slit lamp - cup-disc ration - cupping
visual field assessment - peripheral field loss?
central corneal thickness assess

Question 10

when does treatment start for OAG?

Answer 10

if pressure reaches 24mmHg - normal is 10-21

Question 11

what methods can be used to manage OAG?

Answer 11

360 laser trabeculoplasty
prostaglandin analogue eye drops
other eye drops

Question 12

what is the definitive treatment for OAG?

Answer 12

trabeculotomy

Question 13

how does the 360degree laser trabeculoplasty work?

Answer 13

laser directed at trabecular meshwork to improve drainage

Question 14

what are pros and cons of 360 laser in OAG?

Answer 14

pros - may delay need for eye drops
cons- may need repeat surgery
- still does not officially treat

Question 15

how do prostaglandin analogue eye drops work?

Answer 15

increase uveoscleral outflow- reduce pressure

Question 16

what are pros and cons of prostaglandin eyedrops?

Answer 16

pros - eyelash growth
cons- eyelid pigmentation and iris pigmentation

Question 17

other eye drops reduce aqueos humour, what are they?

Answer 17

timolol - BB
dorzolamide - carbonic anhydrase inhib
bromonidine - sympathomimetics

Question 18

name an example of prostaglandin analogue to treat OAG?

Answer 18

lantanoprost

Question 19

when would trabeculectomy be offered?

Answer 19

when other methods have failed

Question 20

how does trabeculectomy work?

Answer 20

creates a new channel from anterior chamber through sclera to a new location under conjunctiva
causes a bled on conjunctiva
then allows reabsorbtion to general cicurlation