Glaucoma Flashcards
what is glaucoma? - definition
A group of diseases leading to optic neuropathy. characterised by abnormal disc appearance/ cupping and VF patterns. IOP is a common factor
what are the three main types of glaucoma
POAG
PACG
SACG
List 10 features of a glaucomatous disc
- Notching
- PPA
- APON
- C:D>0.5/0.6
- not following the ISNT rule
- Pallor
- Thinning of NRR
- Disc haemorrhage
- Laminar dots
- asymmetry between discs
describe the different types of POAG
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
describe the different types of angle closure glaucoma
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
list the medications prescribed for POAG
- prostaglandin analogue or beta blocker
- prostaglandin analogue or beta blocker
- carbolic anhydrase or alpha 2 antagonist
4 pilocarpine
what is the mechanism of prostaglandin analogues
to increase analogues which increases uveoscleral outflow. decreasing iop be 30-35%
what is the mechanism of beta blockers
reducing production of aqueous humour by blocking sympathetic nerve endings in the cilary body causing a drop in iop
what are the side effects of prostaglandin analogues
mild punctate keratopathy
mild conjunctival hyperaemia
increase in iris pigmentation
lengthening of eyelashes
what are the side effects of beta blockers
punctate keratopathy
dry eye
burning/ stinging sensation
explain YAG iridotomy
holes are made in the iris to relieve pupil block reducing IOP. indications include PACG, narrow angles and pupil block
explain argon laser trabeculoplasty
laser is use to open the TM, used in POAG and SOAG
explain trabeculectomy
creates a scleral drainage flap to allow drainage from the anterior chamber to the conjunctiva
what is the pressure theory
trabecular dysfunction, trabecular meshwork becomes less effective in allowing aqueous to flow through schjlemms canal causing mechanical disc damage
what is the vascular theory
in normal pressure cases damage is created due to poor blood supply to the ONH this reduced blood flow caused increased IOP sensitivity
list the types of secondary open angle glaucoma
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
what type of glaucoma is PXF explain how it would be observed on slit lamp
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
what type of glaucoma is associated with Krunkenburg spingles
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
what are risk factors for glaucoma
age
iop
family history
race
cct
pxf
pds
steroids
migranes
raynaulds
heart disease
hypertension
what test would you conduct on a px with suspect glaucoma?
Contact tonometry
van herrick
VF - full threshold
gonioscopy
slit lamp
volk, fundus photographs, OCT
how to manage OHT
routine referal to reduce IOP - topical hypotensives
advise to eat dark chocolate, red grapes, magnesium
how to structure management
presenting complaint
findings
cause
prognosis
management
recall
