Glaucoma

Question 1

what is glaucoma? - definition

Answer 1

A group of diseases leading to optic neuropathy. characterised by abnormal disc appearance/ cupping and VF patterns. IOP is a common factor

Question 2

what are the three main types of glaucoma

Answer 2

POAG
PACG
SACG

Question 3

List 10 features of a glaucomatous disc

Answer 3

1. Notching
2. PPA
3. APON
4. C:D>0.5/0.6
5. not following the ISNT rule
6. Pallor
7. Thinning of NRR
8. Disc haemorrhage
9. Laminar dots
10. asymmetry between discs

Question 4

describe the different types of POAG

Answer 4

POAG - asymptomatic until advanced or paracentric defect, raised/ normal pressures, abnormal VF, abnormal disc appearance/ cupping, angles open, wide anterior chamber
NTG - As above but normal pressure

Question 5

describe the different types of angle closure glaucoma

Answer 5

PACG - IOP may be raised or normal, VF abnormal, narrow angle, risk factor Asian decent, hypermetropia >+2.00, lens thickening age related, small axial length, pupil dilation and shallow anterior chamber.
Chronic - asymptomatic like POAG, happens as iris progressively increases contact with trabecular meshwork.
intermittent - angles are narrow but open, px may complain of brow pain and/or haloes. these may be especially noticeable in dark environments eg. cinema as pupil dilation will obstruct TM
Acute - end stage, emergency, vision at risk, px will be in pain which will get worse on movement or touch, eye will be red, cornea green/blue haze, mid dilated fixed pupil. IOP > 40mhg iritis may be present. happens due to pupil dilation.
Plateau iris syndrome - anteriorly displaced ciliary body
secondary angle closure glaucoma - happens due to an underlying pathology. this can be due to pseudo exfoliation, uveitis, trauma, lens thickening and reubeosis

Question 6

list the medications prescribed for POAG

Answer 6

1. prostaglandin analogue or beta blocker
2. prostaglandin analogue or beta blocker
3. carbolic anhydrase or alpha 2 antagonist
   4 pilocarpine

Question 7

what is the mechanism of prostaglandin analogues

Answer 7

to increase analogues which increases uveoscleral outflow. decreasing iop be 30-35%

Question 8

what is the mechanism of beta blockers

Answer 8

reducing production of aqueous humour by blocking sympathetic nerve endings in the cilary body causing a drop in iop

Question 9

what are the side effects of prostaglandin analogues

Answer 9

mild punctate keratopathy
mild conjunctival hyperaemia
increase in iris pigmentation
lengthening of eyelashes

Question 10

what are the side effects of beta blockers

Answer 10

punctate keratopathy
dry eye
burning/ stinging sensation

Question 11

explain YAG iridotomy

Answer 11

holes are made in the iris to relieve pupil block reducing IOP. indications include PACG, narrow angles and pupil block

Question 12

explain argon laser trabeculoplasty

Answer 12

laser is use to open the TM, used in POAG and SOAG

Question 13

explain trabeculectomy

Answer 13

creates a scleral drainage flap to allow drainage from the anterior chamber to the conjunctiva

Question 14

what is the pressure theory

Answer 14

trabecular dysfunction, trabecular meshwork becomes less effective in allowing aqueous to flow through schjlemms canal causing mechanical disc damage

Question 15

what is the vascular theory

Answer 15

in normal pressure cases damage is created due to poor blood supply to the ONH this reduced blood flow caused increased IOP sensitivity

Question 16

list the types of secondary open angle glaucoma

Answer 16

phacomorphic glaucoma - precipitated by an intumescent cataract lens, history of gradual impairment or vision or increasing myopia.
Ectopia lenitis - displacement of the lens from normal location resulting in complete or partial dislocation.
intraocular tumours
reubeosis iritis - caused by a diffuse and chronic retinal ischemia. caused by diabetes, iris neovascularisation or steroids.
pseudoexfoliation - blocking of the trabecular meshwork cause by dandruff like material
pigment dispersion syndrome reverse iris block
uveitis - inflammation of the trabecular meshwork
trauma - can cause detachment of the cilary body

Question 17

what type of glaucoma is PXF explain how it would be observed on slit lamp

Answer 17

secondary open angle
on slit lamp this would be observed as dandruff like materials. christmas tree like deposist on the lens
central disc PXF
peripheral band PXF
dandruff like material on pupil margin

Question 18

what type of glaucoma is associated with Krunkenburg spingles

Answer 18

pigment dispersion syndrome, this is cause by rubbing of the posterior pigment layer of the iris creating vertical spindles called krunkenberg spindles. an increase of IOP is due to reverse pupil block.
on slit lamp it would be observed as pigment dispersion on corneal endothelium, vertical spindle shaped distribution, melanin in aqueous

Question 19

what are risk factors for glaucoma

Answer 19

age
iop
family history
race
cct
pxf
pds
steroids
migranes
raynaulds
heart disease
hypertension

Question 20

what test would you conduct on a px with suspect glaucoma?

Answer 20

Contact tonometry
van herrick
VF - full threshold
gonioscopy
slit lamp
volk, fundus photographs, OCT

Question 21

how to manage OHT

Answer 21

routine referal to reduce IOP - topical hypotensives
advise to eat dark chocolate, red grapes, magnesium

Question 22

how to structure management

Answer 22

presenting complaint
findings
cause
prognosis
management
recall