Macular Degneration Flashcards
What are the two types of macular degeneration?
Wet and dry
What kind of vision is lost with AMD?
Central vision as the macular is involved
Peripheral vision is maintained
What is the most common cause of blind and partially sighted registration in the elderly?
Macular degeneration
What are the symptoms of AMD?
Gradual loss of central vision
Often very slow progression- but Wet AMD can cause vitreous haemorrhage which is a cause of acute painless visual loss.
Distorted central vision
Which is the most common form of AMD?
Dry form
What is the precursor lesions in dry AMD? What are the two types?
Drusen are the pre-cursor lesions. There are two types-
Hard Drusen- Round yellow with well defined boundaries
Soft Drusen- (Cause AMD) soft boundaries, grow and come together
What is the underlying pathology of wet AMD?
Characterised by choroidal neovascularisation- There is formation of abnormal blood vessels beneath the retinal pigment epithelium (RPE) layer of the retina.
These penetrate into the retina and macular region and cause bleeding
Bleeding causes scarring which causes visual loss- forms circular scars called disciform scars
What type of scar is produced in wet AMD?
Disciform Scar- this is end stage. Produced due to bleeding underneath the retina. Scar is underneath the retinal as blood vessels can be seen overlying it.
What is the process under-pinning wet AMD?
Choroidal neo-vascularisation- this is blood vessel formation in the choroid which is found beneath the retina and the retinal pigment epithelium
What are drusen made up of?
Yellow, lipid deposits.
There are hard and soft drusen. Soft drusen are problematic.
What change is seen with dry AMD?
Soft drusen come together leading to Geographic Atrophy
What are soft drusen a sign of?
Early dry AMD
What growth factor stimualtes choriodal neovascularisation?
VEGF
What are some strong risk factors for AMD?
Increased age
Smoking
Family History
Genetic- Complement Factor H Gene
What is the treatment for dry AMD?
Little treatment available
Low vision aids such as magnifying glasses
Vitamins- in in patients with advanced AMD in one eye- high dose zine and anti-oxidant vitamins help prevent deterioration in other eye
Severely sight impaired registration (Think social reasons)