Glaucoma Flashcards
What is glaucoma?
A condition characterised by optic disc cupping and visual field loss, in which the IOP is sufficiently raised to impair normal optic disc function
What is the different between primary and secondary glaucoma?
Primary- no cause apparent
Secondary- cause known e.g. trauma
What are the different types of primary glaucoma?
Primary open angle glaucoma
Primary acute angle closure glaucoma
What are some causes of secondary glaucoma?
Inflammation
Trauma
What is raised IOP?
IOP above 21mmHg
How is primary open angle glaucoma defined?
IOP>21mmHg (Normal is between 10 and 21)
Open aqueous drainage outflow
Cupping of the optic disc
Visual field loss- peripheral
What is ocular hypertension? How does it differ from glaucoma?
Raised IOP (>21mmHg) but no cupping or visual field changes. For it to be glaucoma there must be cupping of the optic disc and visual field loss. Glaucoma can occur with pressures below 21mmHg.
Is IOP constant?
No it has diurnal variation, time should be recorded when measuring IOP
What are some risk factors for primary open angle glaucoma?
Increasing age Steroids Diabetes Family history High myopia- short sighted
What are the symptoms of primary open angle glaucoma?
Asymptomatic in most
Never any pain
Can cause loss of peripheral vision which may become noticable
What is used to measure IOP?
Goldmann Applanation Tonometer- presses against the eye to measure the pressures
What is seen at the optic disc?
Cupping of the optic disc >0.5
Pallor of the optic disc
Asymmetry of the cup to disc ratio
What is a normal cup to disc ratio?
Less than 0.3
What is a vascular complication of glaucoma?
Central vein occlusion
Describe the visual field loss in glaucoma?
Initially nasal step
Then superior and inferior arcuate scotomas
Temporal and central islands
Complete field loss= Blindness
How can visual fields be tested?
Goldmann Fields- The one with the big disc thing
Humphrey Fields- Automated, computer shines light and works out visual fields by which lights are detected
Why is there often a delay to diagnosis of glaucoma?
It is asymptomatic initially
How is glaucoma monitored?
Monitor IOP, Visual Field Changes, Cupping of the optic disc
What are the medical treatments for glaucoma?
Topical Eye drops-
- Prostaglandin analogues (e.g. Latanoprost)- Increase uveo-scleral outflow
- Beta Blockers (e.g. Timolol)- decrease aqueous production. Not if asthma or COPD.
- Carbonic Anhydrase Inhbitiors (e.g. dorzolamide) decrease aqeous production
- Alpha 2 agonists (e.g. Brimonidine) decrease aqeous production and increase uveo-scleral outflow
Systemic (if emergency or temporary drop needed)-
Acetazolomide- Carbonic Anhydrase Inhibitor
What topical agents may be used in glaucoma?
Prostaglandin analogues
Beta blockers
Carbonic anhydrase inhibitors
Alpha 2 agonists
(add in that order)
What is a prostaglandin analogoue example?
Latanoprost
What is a beta-blocker eye drop used for glaucoma?
Timolol
What is a topical carbonic anhydrase inhibitor used for glaucoma?
Dorzolamide
What is an example of a topical alpha 2 agonist used for glaucoma?
Brimonidine
