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15 Cards in this Set
- Front
- Back
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What is AMD? |
Disease of over 50 year olds. Results in progressive central vision loss, usually bilateral. Most common form of blindness. |
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What is the pathophysiology of dry AMD?
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Soft drusen deposits due to focal thickening of Bruche's membrane (RPE), choroidal atrophy and pigmentary changes. |
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What is the pathophsyiology of wet AMD?
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Most aggressive form of AMD. Choroidal neovascularisation, initially proliferates under Bruche's membrane. Subsequently penetrates Bruche's membrane to lie in the retina. |
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How can CNV be characterised? |
Position in relation to fovea - extrafoveal (>200micrometres), juxtafoveal (1-199) or sub foveal (under fovea) Leakage type - classic (obvious), occult, mixed. |
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How does dry AMD present?
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Slow and gradual loss of central vision related to difficulty in reading and recognising faces. |
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How does wet AMD present?
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Distortion in vision and sudden loss of central vision. |
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What are the risk factors for AMD? |
Increasing age Smoking Hypertension Hyperlipidaemia Low antioxidant levels in blood |
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How is dry AMD treated? |
No real treatment Try visual rehabilitation Possibility that vitamins may slow down progression of dry AMD |
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What are the main broad treatment options for wet AMD? |
Focal laser coagulation Photodynamic therapy Pharmacological agents Surgery |
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What are the criteria that make some eligible for focal laser coagulation? |
Small extra-foveal lesions, presence of classic CNV with well demarcated lesion boundaries. |
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What are the drawbacks of focal laser coagulation? |
Laser can cause immediate irreversible damage to retina leading to absolute scotoma and loss of visual acuity Leakage persists or recurs in 50% of treated patients |
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What is the agent used in PDT? How does it work? |
The agent is visudyne. It in injected and causes localised endothelial cell damage in the CNV resulting in thrombus formation and occlusion of abnormal vessels. |
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What is the mechanism of the pahrmacological agents used in wet AMD? |
They iterrupt the factors which stimulate or maintain the growth of endothelial cells in the CNV (especially VEGF). |
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What are the names and actions of the main anti-VEGF treatments in wet AMD? |
Pegaptanib sodium (Macugen) - anti-VEGF, anti-angiogenic and anti-permeability action Ranizumab - Lucentis - blocks all isoforms in VEGF. Maintains vision in 95% of cases. Aflibercept - blocks all isoforms of VEGF |
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What surgery is used in the treatment of wet AMD? |
Vitrectomy and submacular excision of CNV. |
