Macular degeneration Flashcards
Define macular degeneration
Potentially progressive disorder of the macula that typically affects people aged over 50 years
What are the types of macular degeneration
Early: low/medium/high risk of progression (based on size of drusen)
Late:
- Intermediate: Retinal pigment epithelial (RPE) degeneration and dysfunction
- Wet active: Classic choroidal neovascularization
- Wet inactive: fibrous scar, atrophy or fibrosis secondary to a tear
- Dry: geographic atrophy with significant visual loss (breakdown of light-sensitive cells in the macula causes one or more sharply demarcated areas of partial or complete depigmentation (atrophy) of the RPE)
Risk factors for macular degeneration
Increasing age
Smoking, 2-3 fold risk (There is a dose-response relationship — the risk increases with the number of pack-years of smoking)
Hypertension
Cardiovascular disease
Presence of AMD in the other eye
Obesity
Diet: low omega 3/6, vitamins ACE, carotenoid, zinc, high saturated fat and cholesterol, high glycaemic index food
Sedentary lifestyle
Family history of AMD
Northern European ancestry
epidemiology of macular degeneration
Commonest cause of severe irreversible visual impairment in older adults in the developed world.
Causes 2/3 of registrations of visual impairment or blindness in the UK
Typically >50yo
Symptoms of macular degeneration
Often asymptomatic
Blurred/distortion of vision: Central first
Metamorphopsia: distortion of vision, where straight lines (such as window blinds) appear crooked, wavy, or bent.
Scotoma: black or grey patch affecting their central field of vision.
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Light glare
Loss/decreased contrast sensitivity (telling between different shades)
Size/colour of objects appearing different in each eye
Abnormal dark adaptation
Photopsia - perception of flickering/flashing lights
Visual hallucinations (Charles Bonnet syndrome)
Difference in presentation of dry and wet macular degeneration
Dry (90%)
Slow macular degeneration over 1-2 years
Geographic atrophy: GRADUAL visual deterioration e.g. difficulty with reading, initially with the smallest sizes of print and then later with larger print.
Wet (10%)
Rapid visual decline (days-weeks) with distortion and macular haemorrhage
Neovascular AMD: suddenly become unable to read, drive, and see fine detail such as facial expressions and features.
Differentials for macular degeneration
Refractive error
Fuch’s endothelial dystrophy
Cataracts
Primary open angle glaucoma
Posterior vitreous detachment
Vitreous haemorrhage
Retinal detachment
Signs of macular degeneration on examination
Visual acuity may be reduced.
Fundoscopy
- Drusen— a frequent feature in the early stages of disease (White fluffy spots around the macula)
- Pigmentary, exudative, haemorrhagic, or atrophic changes affecting the macula.
Investigations for macular degeneration
Dry: Slit lamp biomicroscopy (identify drusen and pigmentary/haemorrhagic/atrophic changes)
Wet: fluoroscein angiography (confirm diagnosis)
Both: optical coherece tomography
Colour fundus photography
Indocyanine green agniography: visualise choroidal circulation
Management for macular degeneration
Refer urgently to an ophthalmologist (seen ideally within 1 week) → fast track macular or retina clinic
Conservative
Stop smoking
Driving: inform DVLA if BILATERAL
Self-monitoring advice
Certification of visual impairment
Low vision services: magnifiers, lighting, tactile aids, electronic aids
Group based rehabilitation for independence
Medical
Anti-VEGF intra-vitreal injection e.g. ranibizumab, bevacizumab
Laser photocoagulation
Photodynamic therapy with verteporfin
Complications of treatment for macular degeneration
Photodynamic therapy: Photosensitivity reaction
anti-VEGF: Endophthalmitis, traumatic lens injury, and retinal detachment
Complications of macular degeneration
Visual impairment and blindness.
Complications of visual impairment.
- Depression (44%)
- Visual hallucinations (Charles Bonnet syndrome)
vFalls and fractures
- Limitations in mobility/ADLs/physical performance
- Reduced quality of life
Prognosis for macular degeneration
Central visual loss is common, but total visual loss is extremely rare in people with age-related macular degeneration (AMD)
Generally, early and intermediate AMD is not associated with disturbances of central visual function — when vision loss occurs it is usually due to the development of advanced AMD.
Progression to advanced: 1.3% if low risk, 18% if intermediate AMD
With treatment, about a third of people will gain some improvement in vision. The majority will maintain vision at their current level, but about 10% will not respond to therapy.
