Age Related Macular Degeneration Flashcards
Define Age Related Macular Degeneration (AMD).
A degenerative disease of the retina typically leading to central vision impairment caused by deposits under the retinal pigment epithelium or neovascularization
What are the 2 types of AMD?
- DRY (non neovascular) AMD- characterised by drusen which are lipid rich extra cellular deposits under the retinal pigment epithelium and atrophic changes
- WET (neovascular) AMD- characterised by growth of new blood vessels underneath the macula.
Which type of AMD is more common?
DRY AMD 90%
Describe the pathophysiology of DRY AMD.
Deposition of yellow whitish material consisting of lipids, vitronectin and other proteins(drusen) in the retinal pigment epithelium and between it and bruch membrane leading to slow progressive atrophy of the local retinal pigment epithelium(centrally or pericentally)
Describe the pathophysiology of WET AMD.
Choroidal neovascularization between the retinal pigment epithelium and bruch’s membrane leading to leaking of intravascular serous fluid and blood hence, sudden localized elevation of the macula and/or detachment of the retinal pigment epithelium.
Give 5 risk factors of AMD.
MODIFIABLE RISK FACTORS
Smoking
Low dietary intake of antioxidants
Sun exposure
Obesity
NON MODIFIABLE
Old age
Genetics
How does AMD present clinically?
Late stage
-Central visual acuity decline
- Need more bright light
- Straight lines looking wavy
- Scotoma(visual field abnormality)
Mention 3 differential diagnosis of AMD.
- Retinal detachment
- Open angle glaucoma
- Central retinal artery occlusion
- Cataract
- Drug toxicity
What important examination should be done for AMD?
Amslers grid
What is the supportive management for AMD?
- Visual and reading aids e.g magnifying glass
- Avoid risk factors
- Improve diet
- Antioxidant therapy, vitamin A,C and E
What is the 1st and 2nd line treatment of WET AMD?
First line: injection of ANTI-Vascular Endothelial Growth Factor(VEGF) into the vitreous body e,g ranibizumab.
Second line: when anti- VEGF is contraindicated
- Laser photocoagulation: direct thermal coagulation of neovascularization
- Photo dynamic therapy: intravenously administered dye is activated in the eye by laser light which causes local toxic effects leading to thrombosis of subretinal neovascularization
What is the prognosis of AMD?
- It’s chronic progressive course for both types
- Dry AMD has a significantly better prognosis than wet AMD
- Complete loss of vision is possible though rare
Mention 3 complications of AMD.
- Retinal detachment
- Charles bonnet syndrome
- Depression
- Falls and fractures
