primary open-angle glaucoma (POAG)

Question 1

what are glaucomas?

Answer 1

optic neuropathies associated with raised IOP

Question 2

how are glaucomas classified?

Answer 2

based on whether the peripheral iris is covering the trabecular meshwork

Question 3

what is the importance of the trabecular meshwork?

Answer 3

drainage of aqueous humour from anterior chamber of the eye

Question 4

what happens in open angle glaucoma?

Answer 4

the iris is clear of the meshwork

Question 5

what are the risk factors for POAG a.k.a. chronic simple glaucoma?

Answer 5

• age (in 2% of >40 y.o.)
• genetics: 1˚ relatives of an OAG pt have a 16% chance of developing it
• black pts
• myopia
• HTN
• DM
• corticosteroids

Question 6

what are the features of POAG?

Answer 6

• peripheral visual field loss (nasal scotomas progressing to ‘tunnel vision’)
• decreased visual acuity
• optic disc cupping

Question 7

what are the fundoscopy signs of POAG?

Answer 7

1. optic disc cupping (cup-to-disc ratio >0.7)
2. optic disc pallor = optic atrophy
3. bayonetting of vessels (vessels have breaks as they disappear into deep cup and re-appear at base)
4. additional features: cup notching, disc haemorrhages

Question 8

how do you investigate for POAG?

Answer 8

1. automated perimetry to assess visual field
2. slit lamp examination with pupil dilatation to assess optic nerve and fundus
3. applanation tonometry to measure IOP
4. central corneal thickness measurement
5. gonioscopy to assess peripheral anterior chamber configuration and depth
6. assess risk of future visual impairment: use RFs such as IOP, central corneal thickness (CCT), fam hx, life expectancy

Question 9

how should you manage pts with positive fam hx of glaucoma?

Answer 9

annual screening from age 40 years

Question 10

what is POAG associated with?

Answer 10

myopia

AACG - hypermetropia

Question 11

how does untreated glaucoma affect vision?

Answer 11

causes visual field defects

commences in peripheries
if untreated, eventually leads to tunnel vision