glaucoma

Question 1

what is glaucoma

Answer 1

refers to a group of disorders characterised by the development of an optic neuropathy with characteristic changes at the ONH and loss of retinal ganglion nerve fibres

this process leads to the eventual development of a VF defect which are consistent with loss of nerve fibre layer ganglion cells

Question 2

how much of population has glaucoma

Answer 2

~2% of population over 40 has glaucoma

Question 3

peripheral anterior synechiae vs posterior synechiae

Answer 3

PAS refers to a condition in which the peripheral iris adheres to the angle (cornea)

posterior synechiae - posterior iris surface attaches to lens capsule

Question 4

ocular hypertension

Answer 4

OHT is defined as a IOP greater than 21mmHg in the absence of disc or field damage

not actually glaucoma but higher IOP is a significant risk factor for developing POAG due to poor drainage of AH

Question 5

primary open angle glaucoma

Answer 5

IOP above 21mmHg with damage to optic disc and VF defect

Question 6

normal tension glaucoma

Answer 6

NTG = IOP less than or equal to 21mmHg with associated disc + field damage

Question 7

acute ACG signs

Answer 7

• red eye
• fixed mid-dilated pupil
• hazy cornea
• iritis
• IOP >40mmHg
• shallow AC

Question 8

acute ACG symptoms

Answer 8

• blurred vision
• haloes around lights
• brow ache/ headache
• nausea, feeling generally unwell

Question 9

optic disc glaucoma signs

Answer 9

• C:D above 0.5 is suspicious
• greater than 0.2 difference in C:D
• NRR loss + pallor
• PPA
• nasalisation of BVs
• APON (acquired pits of ON)
• haemorrhage
• lamina cribrosa dots

Question 10

bayonetting of BVs

Answer 10

if BVs bend or kink sharply when they pass over the edge of the cup

Question 11

APON

Answer 11

acquired pit of optic nerve

highly focal loss of tissue which usually develops at infero/superotemporal part of optic disc

tend to see BVs disappearing into these pits + popping out other side

Question 12

order of prescribing glaucoma drops

Answer 12

1. prostaglandin analogue (e.g., latanoprost, bimatoprost)
2. beta blocker (e.g., timolol)
3. carbonic anhydrase inhibitor (dorzolamide) or alpha 2 agonist (brimonidine)
4. pilocarpine

Question 13

POAG risk factors

Answer 13

• > 40
• black ethnicity
• fam hx 1st degree relative
• myopia >4D
• diabetes/ hypertension
• peripheral vascular disease

Question 14

CAG risk factors

Answer 14

• age >40
• female
• Asian ethnicity
• hyperopia
• family history
• short axial length/ shallow AC
• cataract

Question 15

SIGN referral guidelines for IOPs

Answer 15

IOPs >25mmHg irrespective of CCT

IOP 21-25 + CCT <555nm + 65 or under

IOP <26 + CCT equal or > 555 = monitor

Question 16

mechanical vs vascular theory

Answer 16

mechanical - high IOP damages ONH

vascular - poor ONH perfusion due to lack of blood flow

Question 17

NTG risk factors

Answer 17

• japanese ethnicity
• myopia
• female
• Raynaud’s phenomenon
• migraine
• thin cornea
• thyroid disease
• systemic hypotension

Question 18

ACG management

Answer 18

• peripheral iridotomy
• selective laser trabeculoplasty
• trabeculectomy
• cataract extraction

Question 19

peripheral iridotomy

Answer 19

a hole is created to allow a drainage of aqueous humour through a different channel

YAG laser

for AACG or narrow angles

Question 20

selective laser trabeculoplasty

Answer 20

open angle

laser makes holes in trabecular meshwork to improve outflow of aqueous humour