Glaucoma Flashcards
Define glaucoma. (1)
Group of eye diseases where progressive damage to the optic nerve leads to impaired vision/blindness.
What are the characteristics of glaucoma? (4)
Visual field defects
Changes to head of optic nerve
Nerve fibre layer defects
Head of optic nerve becomes damaged when: IOP is high, compromised blood supply, weakness in optic nerve is compromised.
Define suspected glaucoma. (1)
Changes in optic nerve head (optic disc) or visual field that suggest damage.
Define ocular hypertension. (1)
Consistently/recurrent elevated IOP (>21mmHg) and no signs of glaucoma
Define aqueous humour. (1)
Fluid made by the ciliary body in the posterior chamber.
Define anterior chamber angle. (1)
Structure formed where the iris and cornea join the whites of the eyes towards the outside of the eye.
Define Intraocular pressure. (4)
Keeps the eye in the globe shape.
Maintained by balance between aqueous humour production and outflow.
Raised IOP can cause glaucoma by damaging the optic nerve:
- IOP (normal = 10-21mmHg, acute angle closure glaucoma = > 70mmHg)
Drugs used to tx glaucoma either reduce production of aqueous humour or increase its outflow.
What are the main characteristics of intraocular pressure? (4)
Age
Rate
Cause
Mechanism
What are the main characteristics of intraocular pressure? (4)
What are the characteristics of angle closure glaucoma? (3)
Partially closed angle between iris and cornea:
- Blocks trabecular mesh work and prevents IO fluid drainage.
- As IO fluid continues to be produced, the eye pressure increases and optic nerve is damaged.
- Onset can be acute/chronic.
What are the characteristics of open angle glaucoma? (3)
Open angle between iris and cornea:
- Onset is usually insidious, chronic course.
- Bilateral (signs of damage may worsen in one eye)
- Normal tension glaucoma: (High IOP but within normal range)
What is the prognosis for chronic open angle glaucoma without tx? (1)
Usually be asymptomatic until late in its course (visual field defects don’t appear until most of the optic nerve fibres have been lost.)
What is the prognosis for chronic open angle glaucoma with tx? (1)
Blindness (unlikely) but may have visual field defects.
What is the prognosis for acute angle closure glaucoma? (4)
Treated promptly (full recovery)
Irreversible vision loss likely:
- Delay presenting for tx / reducing IOP to normal range.
- Inability to maintain IOP within normal range.
When to suspect Acute ACG? (3)
Acute painful red eye
Common in females, Asian, long-sightedness, older age.
Hx/symptom of:
- Blurry vision
- Headache/eye pain associated with nausea and seeing halos around lights (occurs in evening and relieved by sleeping).
- Use of adrenergics (e.g. phenylephrine) or an antimuscarinics (e.g. TCAs).
- Semi-dilated and fixed pupils
- Tender, hard eye.
Explain the management of acute ACG in emergency situations. (2)
1 drop of pilocarpine 2% (blue eyes)
1 drop of pilocarpine 4% (brown eyes)
Explain the management of acute ACG in secondary care. (2)
Topical and IV drugs to reduce IOP and analgesia.
Tx is surgery (often laser) to allow aqueous humour to flow from the posterior chamber into the anterior chamber.
What are the risk factors of chronic OAG? (7)
Raised IOP
Age
Family Hx of glaucoma
Ethnicity (African)
CS
Myopia (short-sighted)
Diabetes
When to suspect Chronic OAG? (5)
Increased IOP
Visual field defects
Cupped optic disc.
Visual field loss
Detected by optometrist.
Explain the management of chronic OAG. (3)
Ocular HPT: Offer topical prostaglandin analogue to people with IOP >=24mmHg. (E.g. Latanoprost/Travoprost/Tafluprost/Bimatroprost = prostamide). If not tolerated, try another topical prostaglandin analogue first then switch to a topical BB if necessary.
Explain the management of early/moderate COAG. (1)
Early/Moderate COAG: Topical prostaglandin analogue.
Explain the management for advanced COAG. (3)
Advanced COAG - px preference
- (Surgery with augmentation - chemotherapy (mitomycin C or 5-FU) augments surgery by changing wound healing.
- Topical prostaglandin analogues and other topical IOP lowering agents.
- Laser tx (trabeculectomy)
Explain the use of topical prostaglandin analogues. (1)
Reduces IOP by increasing uveoscleral outflow = increasing aqueous humour outflow.
Give e.g. of topical prostaglandin analogues. (4)
Latanoprost/Travoprost/Bimatoprost drops
Combination (Timolol 0.5% +):
- Bimatoprost (Ganfort)
- Latanoprost (Xalacom)
- Travoprost (DuoTrav)
What is the dose of using topical prostaglandin analogues? (1)
OD (usually evening)
What is the licensed age of topical prostaglandin analogues? (1)
> 18 yrs.
What are the local s/e of topical prostaglandin analogues? (5)
Brown pigmentation in iris
Increased pigmentation of peri-ocular skin.
Eyelashes darkening, thickening and lengthening.
Blepharitis/Dry eyes
Ocular pain/irritation
What are the systemic s/e of topical prostaglandin analogues? (2)
Dyspnoea/Asthma exacerbation
Dizziness/Arthralgia/Myalgia/Iritis/Headache/Photophobia
Explain the use of Topical BB. (1)
Lower IOP by reducing aqueous production.
Give e.g. of topical BB. (5)
Betaxolol/Carteolol/Levobunolol/Timolol
Timolol available as LT OD preparation (Nyogel/Timoptol)
Combination (prostaglandin analogues, sympathomimetics or carbonic anhydrase inhibitors)
Sympathomimetics (Brimonidine = Combigan)
With carbonic anhydrase inhibitors (Brinzolomide = Azarga, Dorzolamide = Cosopt)
What is the dose for topical BB? (1)
1 drop OD / BD
Where are the local s/e of topical BB? (7)
Burning
Stinging
Pain
Itching
Redness
Dry eyes
Allergic reactions
What are the systemic s/e of topical BB? (6)
At high doses (more likely): Bradycardia, Bronchoconstriction, Worsening of circulatory disorders, sleep disturbances, hallucinations, fatigue.
Explain the use of topical sympathomimetics. (1)
Reduces IOP by reducing aqueous production and increasing aqueous drainage.
Give e.g. of topical sympathomimetics. (1)
Brinmonidine tartrate 0.2% / Dipivefrine hydrochloride 0.1%
What is the dose of topical sympathomimetics? (1)
1 drop in affected eyes BD approx. 12 hours apart.
What are the local s/e of topical sympathomimetics? (2)
Hyperaemia, burning and eyes stinging.
Dry mouth/abnormal taste in mouth.
What are the common drug interactions of topical sympathomimetics? (1)
CNS depressants
What are the monitoring requirements for topical sympathomimetics? (5)
Alcohol
Barbiturates
Opiates
Sedatives
Anaesthetics
CNS can increase the effect of topical sympathomimetics.
State the main use of carbonic anhydrase inhibitors. (1)
Reduces IOP by reducing aqueous humour secretion.
Give e.g. of carbonic anhydrase inhibitors. (2)
Topical: Brinzolamide/Dorzolamide
Oral: Acetazolamide
What are the local s/e of carbonic anhydrase inhibitors? (5)
Blepharitis
Eye irritation
Pain
Dryness
Blurred vision
What are the systemic s/e of carbonic anhydrase inhibitors? (1)
Uncommon with topical preparations
What are the dosing regimens for topical/oral carbonic anhydrase inhibitors? (2)
Topical: 1 drop BD/TDS
Oral: Acetazolamide 0.25g to 1g daily in divided doses.
What are the interactions for oral carbonic anhydrase inhibitors? (3)
None with topical preparations.
Oral:
- Aspirin (metabolic acidosis)
- Anticonvulsants (Acetazolamide can increase metabolism)
- Ciclosporin (rapid increase in serum ciclosporin level up to 6x in 72 hrs) can be accompanied by renal toxicity.
Explain the use of topical miotics. (1)
Increase the flow of aqeous humour from the eye = reduced IOP.
What is the dose regimen for topical miotics? (1)
1 drop up to QDS (Pilogel) (LT)
one drop nocte.
What are the local s/e of topical miotics? (5)
Burning,itching, lacrimation
Brow ache, loss of accommodation, blurred vision, myopia.
Conjunctival vascular congestion
Vitreous haemorrhage + pupillary block.
Retinal detachment
What counselling is given to patients with COAG? (6)
Application of eye drops (compliance aid)
Wash hands
Remove contact lenses before applying and wait at least 15 minutes before reinserting them.
Shake bottle of eye drops before each use.
Minimise systemic absorption and ADRs by closing their eyes after administering eye drops, gently grass the tear duct against the nose for at least 1 minute.
Replace each bottle after 4 weeks.
What counselling is given to patients who drive and have COAG? (2)
A driver must have good central visual acuity and adequate peripheral vision whilst using their glasses or contact lenses.
If visual field defects are present, need to inform DVLA and to stop driving until a specific test has been performed.
What counselling is given regarding allergies for COAG? (2)
Reactions usually due to preservatives in eye drop but can also be due to active drug.
Px will experience severe itch, eyes/eyelids become red and swollen.
- Decision to withdraw eye drops needs specialist expertise.
- For people with COAG replacement with a preservative free preparation.
What counselling is given to patients regards to medicinal storage for COAGs? (2)
Most are stored in room temperature.
Latanoprost (Xalatan/Xalacom) stored in fridge before opening. Once open - keep in cool place for up to 4 weeks.
What counselling is given to patients who use more than 1 type of eye drop for COAG? (3)
Allow 5 minutes between different eye preps.
Use drops before gels then use ointments last.
Remove contact lenses before applying eye drops.
