Chronic Glaucoma (Open angle) Flashcards
What is Glaucoma?
a group of eye diseases which cause progressive optic neuropathy commonly associated with raised intraocular pressure
What is the most common condition associated with open anterior chamber angle of the eye?
Primary open-angle glaucoma (POAG)
Describe the pathophysiology of primary open angle glaucoma:
- Although the anterior chamber angle is open, there is resistance to the outflow of aqueous humour through the trabecular meshwork into the canal of Schlemm
- This causes increased intraocular pressure which can cause retinal ganglion death and permanent visual loss
Give 6 risk factors of primary open angle glaucoma:
- Increasing age (65+)
2 Afro-Caribbean ethnic origin
3.T2 diabetes - Family history
- Cardiovascular disease
- Myopia
What is myopia?
Short-sightedness
is primary open-angle glaucoma (POAG) chronic or acute?
Chronic
Does primary open-angle glaucoma often affect one or both eyes?
both
True or false: most cases of primary open angle glaucoma are asymptomatic
true
Describe the sequence of peripheral vision loss seen in primary open angle glaucoma:
the superior visual field is lost first, followed by the inferior visual field
What classic fundoscopy finding is associated with primary open angle glaucoma?
cupped optic disc
When does central vision loss occur in POAG?
Central vision loss occurs at the end stage of POAG
Name 5 specialist investigations used to assess primary open angle glaucoma:
1) tonometry
2) fundoscopy
3) visual field assessment
4) gonioscopy
5) central corneal thickness measurement
What ratio is used to assess the health of the optic disc in glaucoma fundoscopy?
optic-cap-to-disc ratio
What is a normal optic-cap-to-disc ratio?
less than 0.5
What does a pale optic disc indicate?
primary optic nerve atrophy.
Why is central corneal thickness measured when assessing primary open angle glaucoma?
intraocular pressure measurement scan be affected by central corneal thickness and so this is done so allowances can be made
What is the IOP threshold for primary open angle glaucoma treatment?
> 24
What is the name of the laser management for primary open angle glaucoma treatment?
360 degrees selective laser trabeculoplasty
What does 360 degree selective laser trabeculoplasty involve?
using short pulses of low energy light to target particular cells in the eye, triggering the eye to build a meshwork that will function effectively to drain aqueous humour
What is the first line eye drop medication used to treat primary open angle glaucoma?
generic prostaglandin analogue such as latanoprost
Other than latanoprost, give 3 other eye drops that are used to treat primary open angle glaucoma:
1) beta blockers (timolol)
2) carbonic anhydrase inhibitors (acetazolamide)
3) parasympathomimetics (pilocarpine)
What are the side effects of latanoprost?
Brown pigmentation of iris/lids/lashes
What surgery is used to treat advanced cases of primary open angle glaucoma?
trabeculectomy
How does trabeculectomy surgery treat primary open angle glaucoma?
creating a channel in the sclera for aqueous humour to drain
What drug is given alongside trabeculectomy surgery to prevent post-operative scarring?
mitomycin C
What is mitomycin-C?
an antimetabolite used during the initial stages of trabeculectomy to prevent excessive postoperative scarring and therefore reduce the risk of failure.
What is the main complication of untreated Glaucoma?
irreversible loss of vision
What is the DVLA policy on driving with glaucoma?
DVLA requires patients to inform them of a new diagnosis of glaucoma if it affects both eyes (group 1 drivers) or one eye for group 2 commercial drivers