Macular Degeneration

Question 1

What is Age-related Macular Degeneration? (AMD)

Answer 1

Potentially progressive disorder of the macula affecting those >50

Commonest cause of severe, irreversible visual impairment in older adults in developed countries (2/3 causes of visual impairment/blindness in the UK)

Question 2

What is the pathophysiology of AMD?

Answer 2

1+ of the following:

• Drusen = collections of lipids accumulating beneath the retinal pigment epithelium, start small but can increase in size and become confluent with progression; appear as pale yellow spots on the retina
• Geographic atrophy = breakdown of light-sensitive cells on the macula +/- fovea
• Retinal pigment changes - hypo/hyperpigmentation

+/-

• Choroidal neovascuarisation = ‘wet AMD’ - new blood vessels develop in the choroid - easily leak/bleed leading to distortion and retinal scarring

Question 3

What are risk factors for developing AMD?

Answer 3

Age increasing
Family Hx
Northern European ancestry

Smoking = main modifiable risk factor, dose-response relationship

Also:
- HTN, CVD, AMD in other eye, obesity, diet (low omega 3+6; low vit ACE; low zinc; high fat + sugar), lack of exercise

Question 4

How does AMD present?

Answer 4

> 50yrs

Blurring/visual distortion

• Including metamorphosia = straight lines appear crooked or wavy
• Scotoma = grey/black patch affecting vision
• Difficulty reading or driving

Light glare
Loss of/decreased contrast sensitivity
Abnormal dark adaptation

Complications:

• Complete blindness
• Depression
• Charles-Bonnet syndrome (hallucinations)
• Falls, fractures
• ADL + QoL impairment

Question 5

What do you find on examination in AMD?

Answer 5

Snellen’s = Reduced visual acuity

Ophthalmoscopy etc: - Drusen
- Pigmentary, exudative, haemorrhagic or atrophic changes affecting the macula

Fluorescein or indocyanine green angiography - to look at leakage from eyes

Optical coherence tomography - 3D images of retina from laser light

Question 6

How do you manage AMD?

Answer 6

Ophthalmology 1wk referral; esp. if rapid onset

Smoking cessation and dietary changes

Driving advice

Practical/occupational support

Anti-Vascular Endothelial Growth Factor (VEGF)

• Stops the neovascularisation and so progression to, or in wet-AMD
• E.g. Ranibizumab
• Given by intravitreal injection monthly for 3/12 then variably afterwards, up to >2yrs

Possible:
- Laser photocoagulation