age related macular degeneration bethan. epidemiology most common cause irreversible visual loss in...

Age Related Macular Degeneration

Bethan

Epidemiology

• Most common cause irreversible visual loss in >50yrs

• 10% > 65-74yrs• 30% > 75yrs• Prevalence increasing with ageing pop• White ? women

Aetiology

• Age• Smoking• Pos fhx• High BP• ? Sunlight• ? Alcohol• ?obesity• Healthy diet & exercise - protective

pathogenesis

• Deposition of colloid bodies (drusen) in macular area between retinal pigment epithelium (RPE) and underlying (bruch’s) membrane

• From age 45• Age related maculopathy• Critical size/ number – ARMD• Early ARMD – vision preserved (small, apigmentary)• Late ARMD – vision affected (large, pigmented)• Two subtypes

Dry

• Atrophic, dry, non exudative, geographic• 90% of cases• Atrophy of neuroretina – • RPE• Photoreceptors (over rpe)• Choriocapillaris (below rpe)

Wet

• Wet, exudative, neovascular• 10% of patients• Drusen lift retinal pigment epithelium from

blood supply• Choroidal vessal growth – sub retinal neo vasc,

(SRNV), retinal angiomatous proliferation• serous fluid accumulation, vessels leak, scars

formed

Differential diagnosis• Refractive errors.• Cataracts.• Some corneal diseases.• Posterior vitreous detachment or retinal detachment.• Retinal artery occlusion or retinal vein occlusion.• Central serous retinopathy.• Cerebrovascular disease.• Pituitary and other neurological tumours.• Some drugs or chemicals including methanol, chloroquine,

hydroxychloroquine, • Rule out diabetes (diabetic maculopathy).• Type 2 membranoproliferative glomerulonephritis.• Various rare ophthalmic conditions to be ruled out by ophthalmology team.

Clinical features

• Bilateral 1 > loss• Deterioration/distortion of central vision –scotoma

– lines, micro/macropsia• Dark patch “shadowy figure” on waking• Visual hallucinations with severe v loss• Incidental at optometrist• Affected adl’s – driving, reading, recognition• Night glare, photopsia, • Sudden deterioration (bleed) +/- floaters

Investigations

• Visual acuity • Fundus – yellow deposits• Slit lamp exam• Optical coherence tomography (OCT)• Fluorescein angiography

Referral

• Ref ophthalmology –within one week• Or optometrist

Management - support

• No effective treatment for dry ARMD• Register blind - ophthalmologist• Social support• Visual rehab – refract to optomise vision,

magnify/ telescope, large print books, house aids

• Counselling – reassure re peripheral vision, advise about DVLA

• Txt of choroidal neovascularisation - criteria

Management –wet ARMD

• Laser photocoagulation – away from fovea• Verteporfin – iv injection activated by argon

laser beam – stabilises condition• Anti VEGF’s – prevent endothelial cell

proliferation – intraocular• PDT & anti VEGF• Surgical options rarely used• Immunomodulation is being explored

ranibizumab

• Monoclonal antibody to vascular growth factor

• Injected into eye 1/12 x3• NICE & RCO criteria –minority ok• 80% slows visual loss• Aims to preserve central vision• Complications - Retinal detachment,

haemorrhage, infection, hypersensitivity

Advice

• See GP if worsening or other eye affected• Stop smoking• ? Prevention...• Healthy diet with antioxidants & carotenoids• High dose vitamin & mineral supplements

Questions