Age Related Macular Degeneration Flashcards
What is ARMD?
Degeneration in the macular that causes a progressive deterioration in vision
-SUDDEN PAINLESS LOSS OF VISION
What is ARMD the most common cause of?
Blindness
What is a key finding in age related macular degeneration?
Drusen seen during fundoscopy
2 types of age related macular degeneration?
WET - 10%
DRY - 90%
Which type of ARMD is worse?
Wet
What is the macular made up of?
4 key layers From bottom to top there is: - Choroid layer -Bruch's membrane -Retinal pigment epithelium -Photoreceptors
What does the choroid layer contain?
Blood vessels that provide blood supply to the macula
What are Drusen?
Yellow deposits of proteins & lipids that appear between retinal pigment epithelium & Bruch’s membrane
When are drusen common?
Wet and dry macular degeneration
When can drusen be common?
<63 micrometres
What can large numbers of large drusen be a sign of?
Macular degeneration
Features common to both wet and dry macular degenration?
Drusen
Atrophy of retinal pigment epithelium
Degeneration of photoreceptors
How is wet MD different to dry MD?
Development of new vessels growing from choroid
What does new vessel growth result in in Wet MD?
The vessels can leak and cause oedema
- Key chemical which stimulates new vessel development is VEGF
What is VEGF?
Vascular endothelial growth factor
Risk factors of age related macular degeneration?
- Age
- Smoking
- White/Chinese ethnic origin
- Family history
- Cardiovascular disease
Presentation of Wet or dry ARMD?
- Gradual worsening central visual field loss
- Reduced visual acuity
- Crooked or wavy appearance to straight lines
Presentation specific to Wet ARMD?
More acute presentation
- Loss of vision over days
- Often progresses to bilateral
Examination findings for ARMD?
Reduced acuity using Snellen chart
Scotoma (central patch of vision loss)
Amsler grid tests (assesses distortion of straight lines)
Fundoscopy (findings=drusen)
Investigations for ARMD?
- Slit lamp biomicroscopic fundus examination (Can diagnose AMD)
- Optical coherence tomography (Diagnoses Wet ARMD)
- Fluorescein angiography (looks in detail at the retinal blood supply)
What is Fluorescein angiography and what does it show?
Photographs retina
- Looks in detail @ blood supply to retina
- Reveal oedema & neovascularisation
Management of dry ARMD?
No specific treatment
- Lifestyle changes eg stop smoking, control BP, Vitamin supplements
Management of wet ARMD?
-Anti-VEGF meds injected directly into vitreous chamber once a month
They slow down progression and can sometimes reverse the disease, typically need to be started within 3 months though
Examples of anti-VEGF meds?
Ranibizumab
Bevacizumab
Pegaptanib
Pathophysiology of ARMD?
New blood vessels grow under the retina
Leakage causes fluid build-up ad eventually scarring
Symptoms of ARMD (wet)?
- Blurred vision
- Diminished or change colour perception
- Visual disturbance
- Visual hallucinations
Treatment of age related macular degeneration wet?
- Anti-VEGF (vascular endothelial growth factor) injection
- Laser coagulation therapy
Presenting complaint of age-related macular degeneration (dry)?
Gradual, painless loss of central vision
Causes of ARMD dry?
- Damage to the cells of the macula as a result of build up of waste products called drusen
- Thickened retina
Symptoms of ARMD dry?
Blurring central vision
Can occur over 5-10 years
Diagnosis of dry agmd?
Amsler grid testing
Fundoscopy
Treatment for Dry ARMD?
Irreversible damage
Treatment based on helping person make the most of their remaining vision
What is dry ARMD?
Accumulation of drusen (proteins, lipids and inflammatory mediators which are by products of retinal epithelial cells
Presnetation of dry ARMD?
Gradual decline in vision
Central vision missing
Investigation of dry ARMD?
On fundoscopy:
- Drusen
- Atrophic patches of retina
Treatment for dry ARMD?
No cure
- Supportive with low vision aids
- Vitamin supplementation
What is Wet ARMD?
Vascular haemorrhages due to neovascularisation in choroid
Why are new vessels in wet ARMD leaky?
They are new and small (like a baby)
What is wet ARMD mediated by?
VEGF
Presentation of wet ARMD?
Rapid central loss of vision
Distortion
- Metamorphosia
- Show them amsler grid to point out distortion
Wet ARMD findings on fundoscopy?
Haemorrhage
Exudate (causes paleness)
Treatment of wet ARMD?
Monoclonal antibodies to VEGF
