[5] Age-Related Macular Degeneration Flashcards
What does the term age-related macular degeneration (AMD) refer to?
Ageing changes that occur in the central area of the retina in people aged 55 years or older
What needs to be true of the changes in the central area of the retina to be classified as AMD?
Must not have any other obvious precipitating cause
What kind of disease is AMD?
Progressive, chronic disease of the central retina
Why is AMD important?
It is a leading cause of vision loss worldwide
What is AMD characterised by?
Appearance of drusen in the macula
What is the appearance of drusen in the macula accompanied by in wet AMD?
Choroidal neovascularisation
What is the appearance of drusen in the macula accompanied by in dry AMD?
Geographic atrophy
In what respects do the forms of AMD differ?
In pathophysiology and progression
What are the characteristic lesions of dry AMD?
- Soft drusen
- Changes in pigmentation (hypopigmentation and/or hyperpigmentation) of the retinal pigment epithelium
Where does the drusen accumulate in dry AMD?
Between the retina and choroid
What does the accumulation of drusen between the retina and choroid in dry AMD cause?
Atrophy and scarring of the retina
What happens to the atrophy in AMD over time?
The atrophy becomes more extensive with time
Can dry AMD progress and cause vision loss without turning into the wet form?
Yes
What % of cases of AMD are the dry form?
90%
Describe the progression of dry AMD
Progression to visual loss is usually gradual, but eventually there is an area of partial or complete atrophy of the retinal pigment epithelium
Does the atrophy of the RPE in dry AMD involve the fovea?
May or may not
What chance to those with dry AMD have of developing wet AMD?
4-12% chance/year
What happens in wet AMD?
New blood vessels grow in from the choriocapillaris under the retina
In relation to the RPE, where to the blood vessels grow in wet AMD?
Spread under or over the RPE, or both
Describe the abnormal blood vessels in wet AMD
Fragile and easily leak
Describe the location of growth of blood vessels in wet AMD
They start off to the side of the retina and grow towards the centre, eventually growing under the macula
How long does the process of blood vessel growth take in wet AMD?
Can take from days to weeks
What are the consequences of abnormal vessel formation in wet AMD?
- Haemorrhage
- Scar formation
What % of cases of AMD are wet AMD?
10%