Glaucoma Flashcards Preview

Opthalmology > Glaucoma > Flashcards

Flashcards in Glaucoma Deck (20)
Loading flashcards...
1

def

optic neuropathy associated with increased intraocular pressure

2

what is the definition of increased intraocular pressure

IOP>21mmHg

3

aetiology

can be split into primary, secondary and congenital causes

1 primary
-acute closed-angle glaucoma
-primary opened-angle glaucoma
-chronic closed -angle glaucoma
2 secondary
-trauma
-uveitis
-steroids
3 congenital
-buphthalmos

4

what is buphthalmos

congenital disorder which gives enlargement of the eyeball
associated with glaucoma

5

epi

increases with age
3rd most common cause of blindness worldwide

6

history

acute closed-angle glaucoma is associated with a painful red eye and impaired vision
primary opened-angle glaucoma is often asymptomatic but there may be peripheral field loss

7

examination

acute closed-angle glaucoma there is a red eye, hazy cornea, loss of red reflex and fixed + dilated pupil
in primary opened-angle glaucoma there are often no signs

8

what does a hazy lens and a hazy cornea indicate

hazy lens indicates cataracts
hazy cornea indicates glaucoma (specifically acute closed-angle glaucoma)

9

what causes visual field loss in glaucoma

increased intraocular pressure compresses and stretches the retinal nerve fibres which leave the optic disk
this causes scotomas and visual field loss

10

what is a scotoma

partial loss of vision or a blind spot in an otherwise normal visual field

11

what causes increased intraocular pressure

decreased outflow of aqueous humour due to:
1 obstruction to outflow of aqueous humour due to the iris and cornea sticking together. this closes the iridocorneal angle and trabecular meshwork/canal of schlemm and causes a rapid and severe rise in IOP (ACAG)
2 reduced outflow of aqueous humour through the trabecular meshwork (POAG)
3 blockage of trabecular meshwork by blood or inflammatory cells

12

what is the pathogenesis of ACAG

there is obstruction to outflow of aqueous humour due to the iris and cornea sticking together
this closes the iridocorneal angle and trabecular meshwork/canal of schlemm
this causes a rapid and severe rise in IOP

13

what is the pathogenesis of POAG

there is reduced flow of aqueous humour through the trabecular meshwork

14

investigations

1 goldmann applanation tonometry
-standard examination to measure IOP
-if raised, indicates glaucoma
2 opthalmoscopy

15

what is normal IOP

15mmHg

16

what is the IOP in POAG

20-40mmHg

17

what is the IOP in ACAG

>60mmHg

18

risk factors

age
black ethnicity

19

what is the relevance of the cup-to-disc ratio in glaucoma

increased ratio could indicate glaucoma

20

what is the risk of glaucoma

it is a progressive optic neuropathy, it causes optic nerve damage which leads to visual field loss