Slide 1 of 31 MPHM13 Eye Conditions Glaucoma
• Glaucoma is a group of eye diseases in which progressive damage to the optic nerve leads to impaired vision and, in a small proportion of people, blindness. • Characteristics: – Visual field defects — arcuate scotomas, nasal steps, and altitudinal loss.
– Changes to the head of the optic nerve — including pathological cupping – Nerve fibre layer defects.
Slide 2 of 31 MPHM13 Eye Conditions Glaucoma • The head of the optic nerve can become damaged by any combination of: – IOP that is abnormally high — most common cause of damage. – The blood supply to the optic nerve is compromised. – There is a weakness in the optic nerve structure or fibres. • Suspected glaucoma is defined as changes in the optic nerve head (optic disc) or visual field that suggest glaucomatous damage (regardless of the intraocular pressure). • Ocular hypertension is a condition defined by consistently or recurrently elevated intraocular pressure (greater than 21 mmHg) and no signs of glaucoma.
Slide 3 of 31 MPHM13 Eye Conditions Background physiology Aqueous humour - the fluid created by the ciliary body in the posterior chamber
Anterior chamber angle The space between the iris and pupil behind and the cornea in front is called the anterior chamber. The anterior chamber angle is the structure formed where the iris and the cornea join the sclera (white of the eye) towards the outside of the eye.
Slide 4 of 31 MPHM13 Eye Conditions Intraocular pressure
• Keeps the eye in the shape of a globe. • IOP is maintained by the balance between production and outflow of aqueous humour. • Raised intraocular pressure can cause glaucoma by damaging the optic nerve. – Intraocular pressure is normally around 10–21 mmHg, but it can be as high as 70 mmHg in acute angle closure glaucoma. • Drugs used to treat glaucoma either reduce the production of aqueous humour, or increase its outflow.
Slide 5 of 31 MPHM13 Eye Conditions Characterising Glaucoma
• 4 main ways: • Age of onset: congenital, infantile, juvenile, or adult. • Rate of onset: acute or chronic. • Cause: Primary (no known cause) Secondary – causes include disease, drugs, developmental disorders (increase in IOP) • Mechanism: Angle closure glaucoma v Open angle glaucoma.
Slide 6 of 31 MPHM13 Eye Conditions Angle closure glaucoma - the angle between the iris and the cornea is at least partially closed. – This blocks the trabecular meshwork and prevents drainage of intraocular fluid. – As intraocular fluid continues to be produced, the pressure within the eye increases and the optic nerve is damaged. Onset can be acute or chronic
Slide 7 of 31 MPHM13 Eye Conditions Open angle glaucoma - the angle between the iris and the cornea is open. – Onset is usually insidious, and the course chronic. – Both eyes usually affected - signs of damage may be worse in one eye. – IOP is usually increased but can be within normal range (normal tension glaucoma).
Slide 8 of 31 MPHM13 Eye Conditions OAG - Chronic course – ACG - Can be acute or usually affects both eyes chronic…Increased IOP will Up to 10x more common cause damage to the optic than ACG nerve
Slide 9 of 31 MPHM13 Eye Conditions Prognosis Chronic open angle Acute angle closure glaucoma glaucoma Without treatment • Will usually be Full recovery is likely for people asymptomatic until late in its treated promptly course — visual field Irreversible loss of vision is defects do not appear until more likely if there is: most of the optic nerve • Delay in presenting for fibres have been lost. treatment. With treatment • Delay in reducing intraocular • Most people with chronic pressure to the normal range. open angle glaucoma will • Inability to maintain not go blind, although they intraocular pressure within will have some visual field the normal range. defects.
Slide 10 of 31 MPHM13 Eye Conditions When to suspect Acute ACG?
• Patient will usually present with an acute painful red eye • More common in females, Asian, long-sighted (require reading glasses), or of older age. • History of/symptoms of: • Blurred vision • Headaches or eye pain associated with nausea and seeing halos around lights; these symptoms typically occur in the evening and are relieved by sleeping. • Use of adrenergic drugs (eg. phenylephrine) or an antimuscarinic drugs (eg. TCA’s) • Semi-dilated and fixed pupil. • Tender, hard eye.
Slide 11 of 31 MPHM13 Eye Conditions Management – Acute ACG
In Emergency Situations: – One drop of pilocarpine 2% in blue eyes/ pilocarpine 4% in brown eyes – Followed by a single dose of oral acetazolamide 500 mg. In secondary care: – Topical and IV drugs to reduce intra-articular pressure and analgesia. – Definitive treatment is surgery (often laser surgery) to allow aqueous humour to flow from the posterior chamber into the anterior chamber.
Slide 12 of 31 MPHM13 Eye Conditions Risk factors for Chronic OAG
• Raised intraocular pressure -the main treatable risk factor for chronic open angle glaucoma • Age - prevalence increases steeply with age. • Family history - risk is increased when a first-degree relative has glaucoma. • Ethnicity - more common in people of black African origin • Corticosteroids - The use of oral, inhaled, or high-potency topical corticosteroids has been associated with increased risk of glaucoma …………….corticosteroids increase the resistance to outflow of the aqueous humour………Most common with eye drop preparations! • Myopia - People who are short-sighted are more likely to develop glaucoma and more likely to develop it at a younger age; the risk increases with severity of myopia • Diabetes mellitus
Slide 13 of 31 MPHM13 Eye Conditions When to suspect Chronic OAG?
• Most commonly detected by an optometrist • Typical features detected: ➢ Increased intraocular pressure ➢ Visual field defects ➢ A cupped optic disc. • In primary care suspect COAG in someone with: ➢ Loss of part of the visual field without other eye symptoms (rare) ➢ Presence of risk factors ➢ People are often not aware that they have a visual field defect, even when it is severe. Pain is typically absent.
Slide 14 of 31 MPHM13 Eye Conditions Management – Chronic OAG
• Ocular hypertension – treatment based on the person's age, IOP, and central corneal thickness.
– Many patients require only monitoring – First-line option in those <65 years old is a topical beta-blocker. – Higher risk or >65 a topical prostaglandin analogue (bimatoprost, latanoprost, tafluprost, or travoprost) is recommended.
Slide 15 of 31 MPHM13 Eye Conditions Management – Chronic OAG
• For early/moderate COAG but treatment is indicated - a topical prostaglandin analogue is recommended first line. • For advanced COAG - options recommended depend on pt preference: – Surgery with augmentation — chemotherapy (mitomycin C or 5-fluorouracil) augments surgery by modifying wound healing. – Topical prostaglandin analogues, and other topical intraocular pressure-lowering agents. – Laser treatment (trabeculectomy).
Slide 16 of 31 MPHM13 Eye Conditions Topical prostaglandin analogues • Lower IOP by increasing uveoscleral outflow and hence increasing the outflow of aqueous humour. • A systematic review conducted by NICE found: – more effective than topical beta-blockers in achieving an acceptable IOP – less likely to experience a respiratory adverse event than with a topical beta-blocker – More likely to develop red eyes than people using a topical beta-blocker – more cost-effective than topical beta-blockers
Slide 17 of 31 MPHM13 Eye Conditions Topical prostaglandin analogues
Examples: – Latanoprost /Travoprost/Bimatoprost drops. • Combination preparations containing timolol 0.5%: – Bimatoprost and timolol — Ganfort®. – Latanoprost and timolol — Xalacom®. – Travoprost and timolol — DuoTrav®.
Dose: One drop daily (usually evening) Not licensed under 18 years
Slide 18 of 31 MPHM13 Eye Conditions Topical prostaglandin analogues
• Local adverse effects: – Increased brown pigmentation in the iris - more noticeable if mixed-coloured iris – Increased pigmentation of peri-ocular skin. – Darkening, thickening, and lengthening of the eyelashes. – Blepharitis/Dry eyes. – Ocular pain and irritation. • Systemic adverse effects are rare: – Dyspnoea/Exacerbation of asthma. – Dizziness/Arthralgia/Myalgia/Iritis/Headache/Photophobia . Slide 19 of 31 MPHM13 Eye Conditions Topical beta-blockers
• Lower IOP by reducing aqueous production. Examples: – Betaxolol/Carteolol/Levobunolol/Timolol – Timolol is also available as Long-acting once daily preparations — Nyogel® /Timoptol®-LA – Combination preparations containing prostaglandin analogues, sympathomimetics, or carbonic anhydrase inhibitors. – Eg. with sympathomimetics: Brimonidine - Combigan® – With carbonic anhydrase inhibitors: Brinzolomide - Azarga® • Dorzolamide — Cosopt® • Doses: One drop once or twice daily (drug dependant)
Slide 20 of 31 MPHM13 Eye Conditions Topical beta-blockers
• Local adverse effects (relatively common) – burning, stinging, pain, itching, redness, dry eyes, allergic reactions to the active drug or preservatives. • Systemic adverse effects – More likely with high doses for prolonged periods. Bradycardia/Bronchoconstriction/Worsening of circulatory disorders/Sleep disturbances/Hallucination/Fatigue. • Interactions - Systemic absorption may follow topical application!!!
Slide 21 of 31 MPHM13 Eye Conditions Topical Sympathomimetics
• Reduce IOP by decreasing aqueous production and increasing aqueous drainage. • Examples – Brimonidine tartrate 0.2%/Dipivefrine hydrochloride 0.1% Dose - One drop in affected eyes BD, approx 12 hours apart. • Local adverse effects: – Hyperaemia, burning, and stinging of the eyes. – Dry mouth and abnormal taste in the mouth, (associated with drainage of the drug into the nasopharynx) Slide 22 of 31 MPHM13 Eye Conditions Topical Sympathomimetics
• Drug interactions: • Central nervous system (CNS) depressants • Monitor closely with alcohol, barbiturates, opiates, sedatives, or anaesthetics. – CNS depressants could potentiate the effects of topical sympathomimetics.
Slide 23 of 31 MPHM13 Eye Conditions Carbonic anhydrase inhibitors
• Reduce IOP by reducing the secretion of aqueous humour. • Examples: ➢ Topical – Brinzolamide/Dorzolamide. ➢ Oral - Acetazolamide • Local adverse effects: – Blepharitis/Eye irritation, pain, dryness/blurred vision. • Systemic adverse effects – uncommon with topical preps
Slide 24 of 31 MPHM13 Eye Conditions Carbonic anhydrase inhibitors
• Topical doses – One drop BD/TDS – drug dependant • Oral Acetazolamide — 0.25 g to 1 g daily in divided doses. • Interactions – none with topical preps • Oral preps: • Aspirin —acetazolamide and high-dose aspirin can result in metabolic acidosis. • Anticonvulsants - acetazolamide can modify the metabolism of some anticonvulsants. • Ciclosporin —can cause a marked and rapid increase in serum ciclosporin levels (up to six-fold in 72 hours)…may be accompanied by renal toxicity.
Slide 25 of 31 MPHM13 Eye Conditions Topical Miotics
• Increase the flow of aqueous humour from the eye, resulting in a decrease in IOP • Pilocarpine Dose: one drop up to QDS……Pilogel® (long-acting) — one drop nocte. • Local adverse effects: – Burning, itching, lacrimation – Brow ache, loss of accommodation, and blurred vision, myopia. – Conjunctival vascular congestion. – Vitreous haemorrhage and pupillary block. – Retinal detachment. Slide 26 of 31 MPHM13 Eye Conditions Patient Counselling - COAG – How to apply eye drops -may need compliance aid: – Wash hands – Remove contact lenses before applying and wait at least 15 minutes before reinserting them. – Shake the bottle of eye drops before each use. – Minimise systemic absorption and ADRs by closing their eyes after administering eye drops, gently press the tear duct against the nose for at least 1 minute – Replace each bottle after 4 weeks.
Slide 27 of 31 MPHM13 Eye Conditions Patient Counselling - COAG
Driving - A driver must have good central visual acuity and adequate peripheral vision while using their glasses or contact lenses. – If there are visual field defects in both eyes, the person is legally required to inform the DVLA and to stop driving until a specific test has been performed • Information: – The Royal National Institute of Blind People (www.rnib.org.uk) – The International Glaucoma Association (www.glaucoma- association.com)
Slide 28 of 31 MPHM13 Eye Conditions Patient Counselling - COAG
• Allergies??? - reactions are usually due to the preservative in the eye drop but can also be due to the active drug. • Pt will experience severe itch, eyes to become red, eyelids red and swollen. • Decisions to withdraw eye drops requires specialist expertise, particularly when disease is severe or more than one type of eye drop is being used. • For people with COAG replacement with a preservative- free preparation is recommended
Slide 29 of 31 MPHM13 Eye Conditions Patient Counselling - COAG
• Storage • Most eye drops should be stored at room temperature, • Latanoprost (Xalatan® and Xalacom®) should be stored in a refrigerator before opening. Once opened - keep in a cool place for up to 4 weeks. • Using more than one type of eye drop??? – Allow at least 5 minutes between using different eye preps – Use drops before gels and use ointments last. • Remove contact lenses before applying eye drops
Slide 30 of 31 MPHM13 Eye Conditions Further reading
• Minor illness or Major Disease by Clive Edwards & Paul Stillman • Ocular Conditions from A to Z part (i) and (ii) Pharmaceutical Journal www.pjonline.com Feb/March 2007 Vol 278 • NICE – CKS Conjunctivitis • NICE – CKS Glaucoma
Slide 31 of 31 MPHM13 Eye Conditions