Eye Flashcards
What is glaucoma?
Progressive optic neuropathy involving damage to optic nerve and associated visual field loss.
What are risk factors for glaucoma?
- High intraocular pressure
- Increasing age
- Family history
- Diabetes
- Hypertension
Glaucoma is the…
…leading cause of preventable vision loss in NZ
What is aqueous humour?
Thin transparent layer of fluid similar to plasma secreted by the ciliary body, filling the anterior and posterior chambers of the eye.
Where is aqueous humour produced?
The ciliary epithelium of the ciliary body.
It flows from the posterior to the anterior chamber.
How is aqueous humour drained?
90% by the trabecular meshwork, 10% by the uveoscleral pathway
What are the three classifications of glaucoma?
Open angle
Closed angle
Congenital
What is the mechanical theory of glaucoma pathophysiology?
Increased IOP –> compression of axonal fibres of the optic nerve –> disrupts axoplasmic flow –> loss of cell bodies and nerve fibres
What is the vascular/ischaemic theory of glaucoma pathophysiology?
Decreased perfusion at the optic nerve –> disturbs vascular autoregulation –> causing changes to systemic haemodynamics
What is the association of IOP and glaucoma?
Increasing IOP does not necessarily correspond with increasing likelihood of glaucoma. IOP fluctuates throughout the day in a normal person; it fluctuates more in a person with glaucoma.
What should be checked when taking history of a patient with suspected glaucoma?
- Previous ocular history: trauma, surgery, inflammation, eye disease
- Systemic disease: current medications etc
- Family history of glaucoma
What is tonometry?
Measure of IOP, Goldmann is gold standard
What is central corneal thickness and why is it measured?
Central corneal thickness is an important risk factor for the development of primary open-angle glaucoma.
What is gonioscopy and why is it measured?
Goinioscopy visualises anterior chamber angle structures and is used to differentiate between different glaucoma sub-types
Management of glaucoma should be done…
…in a stepwise manner
What are the goals of glaucoma management?
Decrease aqueous production
Increase aqueous drainage
What is the first-line treatment of glaucoma?
Prostaglandin analogues
- Bimatoprost
- Latanoprost
- Travoprost
Which prostaglandin analogue is most appropriate?
Latanoprost
- subsidised
- once daily dosing
Prostaglandin analogue MOA?
Increase aqueous outflow via uveoscleral pathway
C/Indications to prostaglandin analogues?
- Allergy
- Intraocular inflammation
- Macular oedema
- Pregnancy
ADR prostaglandin analogues?
Increased thickness and length of eyelashes
Changing eye colour
Dilation of conjunctival blood vessels
What are examples of beta blockers (for ocular use)?
Timolol
Betaxolol
Levobunolol
Which beta blockers are B1 selective?
Betaxolol
C/Indications to beta blockers?
Bradycardia Heart block Asthma (for non-beta selective BBs) Allergy Hypotension Pregnancy
ADR beta blockerss?
Redness
Bradycardia, heart block
Shortness of breath
Hypotension
Beta blocker MOA?
Reduce aqueous production by reducing cAMP levels.
Carbonic anhydrase inhibitor MOA?
Reduces aqueous production by inhibiting carbonic anhydrase
When should carbonic anhydrase inhibitors be initiated?
When other medications (BB, PA) are contraindicated
What are examples of carbonic anhydrase inhibitors?
Brinzolamide 1% (Azopt)
Dorzolamide 2% (Trusopt)
C/Indications to carbonhic anhydrase inhibitors?
Allergy
Moderate renal/hepatic disease
Pregnancy
Carbonic anhydrase inhibitor ADR?
Redness Allergy Burning and stinging Metallic taste Corneal oedema
Alpha agonist MOA?
Decrease IOP by reducing aqueous production and increasing uveoscleral outflow
What are examples of alpha agonists?
Brimonidine (alphagan)
Timolol + brimonidine (Combigan)
C/Indications to alpha agonists?
Allergy
Use of MOAI and TCAs
Severe CV disease
Pregnancy
Alpha agonist ADR?
Ocular allergy Dry mouth and nose Headache Fatigue Redness
Muscarinic agonist MOA?
Increase aqueous outflow via conventional pathway by directly stimulating muscarinic receptors of the ciliary body and the iris sphincter
What is selective laser trabeculoplasty?
Laser treatment to trabecular meshwork, increases aqueous outflow facility.
What is the association of corticosteroid use and glaucoma?
High or moderate responders to corticosteroids may result in an increase in IOP after daily corticosteroid treatment.
What is the pharmacist’s role in glaucoma management?
Compliance
Inform about side effects and drug interactions
What is the 45+5 rule?
From age 45 onwards, have an eye check every 5 years.
What is blepharitis?
Chronic inflammation of the eyelids
What are the causative organisms of blepharitis?
Staph infection
Demodex infection
Seborrhea
What are the symptoms of blepharitis?
Irritated red lids, with crusting of eyelashes and capping of meibomian glands.
What are the meibomian glands and what happens in meibomian gland dysfunction?
Meibomian glands produce oily layer of tear film which prevents tears from evaporating
Dysfunction causes increased evaporation –> dry eye, local infections
What are OTC treatment options for blepharitis?
- Hot compress
- Massage to express glands
- Lid cleaning products (e.g. Systane lid wipes)
- Artificial tear supplements
- Tea tree oil if suspected Demodex infection
What are prescription treatment options for blepharitis?
- Topical antibiotics (Fusidic acid)
- Systemic antibiotics (doxy, azithro)
- Topical steroids (FML)
- Topical cyclosporine`
What are the two types of dry eye?
- Poor quantity of tears
2. Poor quality of tears
What is the management of poor tear QUANTITY?
Add more tears: artificial tear supplements, anti-inflammatory drops
What is the management of poor tear QUALITY?
Improve tear film:
Hot compress, lid massage, steroids to express Meibomian glands
Carmellose
Refresh brand
Hypromellose + Dextran
Poly-tears
Wool fat
Poly Visc
Carbomer
Poly Gel
Polyvinyl alcohol
Refresh Preservative free
Sodium hyaluronate
Hylo-Fresh
Polyethylene Glycol + Hydroxypropyl Guar
Systane Ultra
Other than eye drops, what other treatments exist for dry eye?
Punctal Plus
Topical steroids - FML
Omega 3 supplements
What is a punctal plug?
Small device that blocks tear duct drainage to relieve chronic dry eye
FML MOA?
Inhibits inflammatory response to mechanical, chemical or immunological trauma
What are the management options for allergic conjunctivitis?
- Avoid allergen
- Ocular decongestants/antihistamines (e.g. Naphcon-A)
- Seasonal: mast cell stabiliser (Lomide)
- Combination antihistamine + mast cell stabiliser (Patanol)
What are the benefits of topical eye drug delivery?
Ease of application
Direct application to target site
Small dose of drug required
Rapid onset of action
What are the disadvantages of topical eye drug delivery?
Potential contamination
Requires preservatives
May cause systemic absorption
Limited penetration, fast elimination
What are the benefits of solutions?
Good stability
Ease of preparation
Low cost
What are the disadvantages of solutions?
Fast drainage
Low permeability
Low bioavailability
What are the benefits of ointments?
High viscosity –> reduced drainage –> better absorption –> higher bioavailability
Less likely to be diluted by tears
Lubricating
No stinging
What are the disadvantages of ointments?
Blurred vision
Greasy feeling –> reflex tearing
What are the benefits of emulsions?
Suitable for lipophilic drugs
Lubricating due to oil component
What are the disadvantages of emulsions?
Contains surfactant –> local toxicity
Low stability
High cost
How can we increase ocular bioavailability?
- Shake bottle before use suspensions)
- Apply one drop into lower lid, close eyes and obstruct the duct
- Leave 5 mins before using other drops
