3. Introduction to AMD Flashcards
What is the most common cause of visual impairment in older adults in the Europe?
Late stage AMD
AMD affects people of what age?
Affect people older then 50 years old
Describe what AMD Means
A degenerative disease causing progressive damage to the macular area of the retina, leading to loss of central vision
What are the common complains of patients with AMD?- symptoms
Blurred vision, reading difficulties, visual distortion, problems to adaptation after sunlight exposure.
What are the modifiable and unmodifiable risk factors of AMD
Modifiable risk factors:
1. Smoking
2. Hypertension
3. (Sunlight Exposure)
4. (Heavy Alcohol Consumption)
Unmodifiable risk factors:
1. Age
2. Gender: Women at high risk
3. Genetic predisposition
4. Race: Caucasians
What is seen when someone has early AMD? (2)
- Drusen
- Pigment changes
2 features observed in late AMD
- Geographic atrophy (GA)
- Choroidal Neovasculariation (CNV)
What falls under dry and wet AMD?
Dry AMD: GA, Drusen, pigment changes and Geographic atrophy.
Wet AMD: Choroidal neovascularization (CNV).
What is Drusen?
Initial signs of AMD
Extracellular deposits located between RPE and brunch’s membrane
AMD affects inner or outer retina?
Outer
Describe the size of hard and soft drusen
Hard drusen <63 μm; Soft drusen >63 μm
How are drusens classified depending on its edges?
Distinct or indistinct
What is confluent drusen?
When drusens become bigger and join together- overlap together
Describe the difference between hyperpigmentation and hypopigmentation
Hyperpigmentation: deposits of granules or clumps of gray or black pigment.
Hypopigmentation: RPE depigmentation is characterized by faint areas of various density and configuration without sharply defined borders.
Can pigment changes occur at the same side as drusen?
YES, and presence of both indicates a great risk of progression to late stage AMD compared to seeing one sign alone.
Describe GA
- Well circumscribed areas of depigmentation
- Underlying choroid becomes more visible
Are pharmacological treatments available for GA and NV?
No for GA, yes for NV
Describe CNV
Abnormal newly formed vessels originating from choroid, breach Bruch’s membrane and invade into sub-RPE space and into the subretinal space
The abnormal vessel growth can lead to fibrovascular proliferation, resulting in vitreous haemorrhage and tractional retinal detachment
What is the full form of VEGF and what kind of a molecule is it?
Vascular endothelial growth factor and it is a naturally occurring lipoprotein molecule
Role of VEGF in the pathological cause of AMD
The abnormal changes in the outer retina, due to AMD, stimulate the release of VEGF. VEGF stimulates abnormal neovascularisation (a key characteristic of neovascular AMD). VEGF also induces inflammation and increases vascular permeability
Anti- VEGF Drugs role?
Block VEGF from binding
What are the normal changes seen in the fundus of the eye in terms of drusen
Only druplets seen- small amount of drusen
What is seen in the fundus of a patient with early AMD- drusen and pigment changes
Medium drusen and no pigment changes
What is seen in the fundus of a patient with intermediate AMD- drusen and pigment changes
Large drusen and pigment changes
What is seen in the fundus of a patient with late AMD?
Neovascular AMD and/ or geographic atrophy
What are the 4 techniques used to image AMD, and which of these can be performed by optoms?
Performed by optoms:
1. Colour fundus photography
2. Optical coherence tomography (OCT)
Not performed by optoms:
3. Fluorescein Angiography (FA)
4. Indocyanine Green Angiography (ICGA)
What is seen in the OCT in early AMD
- Dorm shaped elevations in the RPE.
- Hyper-reflective foci: corresponding to spots of hyper-pigmentation.
What is seen in the OCT in late stage AMD
GA: Patches of GA seen as reflective spots on the choroid
CNV: Elevations seen in the RPE as “pointy” shaped (Elevations of the retina). Additionally, the CNV is invading the sub-retinal space- creating blood and fluid to accumulate in this space.
Describe what kind of technique is OCTA and what is seen
This is a non- invasive technique. What is seen: Volumetric angiographic images are seen: showing the structural blood flow through the choroid.
OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. this is a new type of OCT
Describe the procedure for Fluorescein angiography and what observation is made?
Sodium fluorescein injected into patient arm. Image is captured to trace retinal and choroidal circulation. Images are studied for increased or decreased fluorescence: this is used to decided the type on CNV the patient has.
Describe which one is better ICG or fluorescein?
ICG: this green dye has a longer wavelength than fluorescein. Longer wavelength, gives a better visualization of the choroid and this is used to image the ill-defined CNV.
Why is early treatment of CNV important?
Early intervention is important for success of the treatment.
- 2 previous treatments for CNV, not used anymore is?
- PDT
- Surgical e.g, macular translocation
Signs of AMD
Loss of VA, loss of contrast sensitivity, distortion on amsler grid.
