open angle glaucoma

Question 1

glaucoma

Answer 1

optic nerve damage caused by significant rise in intraocular pressure
due to blockage of aqueous humour

2 types

• open angle
• closed angle

Question 2

vitreous chamber is filled with

Answer 2

vitreous humour

Question 3

anterior chamber

Answer 3

between cornea and iris

Question 4

posterior chamber

Answer 4

between lens and iris

Question 5

what are anterior and posterior chambers filled with

Answer 5

aqueous humour - supplies nutrients to cornea

Question 6

aqueous humous is produced by

Answer 6

ciliary body

Question 7

aqueous humour - direction of flow

Answer 7

from ciliary body around lens and under iris, through anterior chamber
through trabecular meshwork, into canal of schlemm

from canal of shclemm it enters general circulation

Question 8

normal intraocular pressure

Answer 8

10-21mmHg

Question 9

what is intraocular pressure created by

Answer 9

resistance to flow of aqueous humour through trabecular meshwork

Question 10

pathophysiology - open angle glaucoma

Answer 10

gradual increase in resistance through trabecular meshwork

more difficult for aqueous humour to flow through and exit eye –> pressure buils up

slow and chronic onset glaucoma

Question 11

pathophysiology - closed-angle glaucoma

Answer 11

iris bulges forward and seals of trabecular meshwork from anterior chamber
preventing aqueous humour from being able to drain away

ophthalmology emergency

Question 12

effect of increased pressure on optic disc

Answer 12

causes cupping of optic disc

optic cup increases in size - indent wider and larger

optic cup > 0.5 size optic disc is abnormal

Question 13

risk factors

Answer 13

inc age
FHx
black ethnic origin
myopia - nearsightedness

Question 14

presentation of open-angle glaucoma

Answer 14

• picked up on routing eye check
• affects peripheral vision first, can progress to tunnel vision

gradual onset

• fluctuating pain
• blurred vision
• halos around night

Question 15

non-contact tonometry

Answer 15

commonly used method for estimating intraocular pressure

shooting puff of air at cornea and measuring corneal response

Question 16

Goldmann applanation tonometry

Answer 16

gold standard for measuring intraocular pressure

device makes contact with cornea and applies different pressures

Question 17

diagnosis

Answer 17

Goldmann applanation tonometry
fundoscopy
visual field assessment

Question 18

Mx principles

Answer 18

aim to reduce intraocualr pressure

treatment started with IO pressure ≥24mmHg

Question 19

Mx

Answer 19

prostaglandin eye drops (e.g. latanoprost) - increase uveoscleral outflow

trabeculectomy - create new channel from anterior chamber

Question 20

other medical Mx options

Answer 20

beta blockers - reduce aqeous humour

carbonic anhydrase inhibotors - reduce production aqueous humour

sympathomimetics - reduce production and increase outflow