AMD

Question 1

What is AMD?

Answer 1

Eye condition which affects the central retina causing vision ,oss

Question 2

What is the macula and how big is it ?

Answer 2

The central area of the posterior pole, subtends an area of 15-20 degrees.

Question 3

What is the fovea?

Answer 3

The fovea is right at the centre of the macula subtending an area of 5 degrees of your visual field.

Question 4

What areas surround the fovea?

Answer 4

Surrounding the fovea is the parafovea and the perifovea is around the parafovea.

Question 5

From centre going out, name the structures of the central retina

Answer 5

Fovea-parafovea-perifovea-macula

Question 6

What are the non-modifiable risk factors of AMD?

Answer 6

Age >50

FH

Genetic

Question 7

What are the modifiable risk factors of AMD?

Answer 7

Smoking

HTN, High fat diet, Lack of exercise

Cataract sx

Question 8

How does cataract surgery affect AMD?

Answer 8

Can be a risk for speeding up any AMD present.If a px has any signs of AMD they’ll be made aware of the risk of it progressing more quickly if they have cataract surgery)

Question 9

Give 5 tests you can do in a suspected AMD px

Answer 9

BCVA – ETDRS chart

Amsler

Reading speed

Mircoperimetry/gross perim = field test for central vision loss

Fundus BIO and OCT

Question 10

What are the 2 symptoms of dry AMD?

Answer 10

Reduced VA

Distortion on amsler

Question 11

What are the 3 symptoms of wet AMD?

Answer 11

Sudden onset of distortions and reduced vision in the affected eye.

Question 12

Why may the symptoms of wet AMD go unnoticed?

Answer 12

This may not be immediately notice if the fellow eye is unaffected, which is why patients at risk of wet AMD are advised to monitor their vision monocularly on a daily basis.

Question 13

What is the very first sign of AMD?

Answer 13

Drusen

Question 14

What are the signs of early AMD?

Answer 14

Soft drusen ≥63µm

RPE hyper/hypo pigmentation

RPE atrophy(cell death)

Question 15

What are the signs of late dry AMD?

Answer 15

Geographic atrophy (GA)

Sharply demarcated area of atrophy

Question 16

What is another name for dry AMD?

Answer 16

Atrophic/non-neovascular

Question 17

What are the signs of wet AMD?

Answer 17

Choroidal neovascularisation

Macular oedema

SRF=sub retinal fluid

Haemorrhages=Sub, intra or pre retinal

Serous detachment of neurosensory retina

RPE detachment (PED) or tear

Exudates

Scarring (disciform)(a neovasuclar scar can form)

Question 18

What are basal laminar deposits?

Answer 18

An sign of early AMD

Lipid deposition in Bruch’s membrane

Question 19

What causes basal laminar deposits to form?

Answer 19

Failure of RPE to process cell debris

Question 20

How are basal laminar deposits seen?

Answer 20

Using electron microscopy so you won’t be able to use OCT to see it

Question 21

What are drusen?

Answer 21

Earliest visible sign

Round yellow deposits

Question 22

Where are drusen located?

Answer 22

Between RPE and bruch’s membrane

Question 23

What are drusen made of?

Answer 23

Deposits of lipofuscin, amyloid, complement factors so they’re waste products

Question 24

How can drusen be described?

Answer 24

Size:
Small <63µm= Very common, ~80% >age 30 yrs

Large ≥63µm=Hallmark of AMD, 26% >age 70 yrs have large drusen

Apperance:
Hard, soft or confluent

Question 25

What is the difference between Hard, soft or confluent drusen?

Answer 25

Hard drusen have well defined margins and soft drusen have ill define margins. Confluent is combination of both

Question 26

How can u measure drusen?

Answer 26

- On a fundus photograph using suitable tools | - On OCT which have calaerpers and can measure the width of the drusen

Question 27

When is drusen normal vs abnormal?

Answer 27

Hard drusen in small numbers= part of normal ageing process/NOT AMD When numerous hard drusen present= risk factor for soft drusen and AMD

Question 28

What are pigmentary changes caused by?

Answer 28

Increased melanin content of RPE, RPE cell profileration, RPE cell migration.

Question 29

What is geographic atrophy?

Answer 29

GA are regions of RPE cell death causing death of photoreceptors causing scotoma Inner retinal layer then start to die too

Question 30

How fast is the vision loss with GA occuring?

Answer 30

Gradual loss of central vision leads to eventual scotoma.

Question 31

How is GA seen in a hospital?

Answer 31

Increased autofluorescence on Fundus Autofluorescence.

Question 32

What are the two features that increase the risk of progression to wet AMD?

Answer 32

Larger, increased number and more confluent drusen with pigmentary changes associated with increased risk progression to advanced AMD

Question 33

Signs of WET AMD?

Answer 33

Choroidal neovascularisation Macular oedema SRF=sub retinal fluid Haemorrhages=Sub, intra or pre retinal Serous detachment of neurosensory retina RPE detachment (PED) or tear Exudates Scarring (disciform)(a neovasuclar scar can form)

Question 34

What causes choroidal neovascularisation?

Answer 34

Hypoxia caused by deposits build up leads to choroidal neovascularisation (haemorrhages which leak under RPE, or subretinal space causes RPE detachment, leaves area of atrophy).

Question 35

What can repeated leakage cause?

Answer 35

Repeated leakage form disciform scar-complete scotoma/untreatable. Macular oedema, exudates

Question 36

How does CNV appear on fundus?

Answer 36

CNV may be seen as a green/grey lesion on a fundus photograph But is easier to detect either using as binocular stereoscopic viewing strategy, such as volk, or on OCT, where the disrupted, raised RPE is clearly visible, and the hyperreflective neovascular membrane is seen beneath

Question 37

What are the first symptoms of wet AMD?

Answer 37

Sudden onset of distortions and reduced vision in the affected eye. This may not be immediately notice if the fellow eye is unaffected, which is why patients at risk of wet AMD are advised to monitor their vision monocularly on a daily basis.

Question 38

Can you get CNV in early AMD?

Answer 38

Yes, CNV develops in 10-15% of people with early AMD.

Question 39

Why causes sub or intraretinal haemorrhages, hard exudates, intra-retinal fluid, or retinal pigment epithelial detachment to form?

Answer 39

The fragile nature of the new vessels means that sub or intraretinal haemorrhages, hard exudates, intra-retinal fluid, or retinal pigment epithelial detachment are common.

Question 40

Where are these new blood vessels growing from and where do they grown into?

Answer 40

From the choroidal circulation, through breaks in Bruch’s membrane, to proliferate beneath the RPE. They can also break through the RPE to grow into the subretinal space.

Question 41

What causes a PED in wet AMD?

Answer 41

It's a separation which occurs between the basement membrane of the RPE and Bruch’s membrane.

Question 42

What is the prognosis of a PED?

Answer 42

May flatten over time, but 1 in 10 is also likely to tear. Either way, the prognosis is poor, and the PED usually leaves an area of atrophy or subretinal scar tissue formation.

Question 43

How do you differentiate wet AMD from hypertensive retinopathy?

Answer 43

CNV leakage causes exudate in the area so it can start to look hypertensive retinopathy. The difference is that Wet AMD is confined to the macula area and it can be bilateral so look in ur history and symptoms whether px has told u that they have hypertensive ret or high blood pressure

Question 44

What are the main symptom differences between dry and wet?

Answer 44

DRY= Gradual loss in central vision, amsler distortion may be reported in later stage WET=Sudden painless loss in central vision, monocular likely but can be binocular, distortion