DIS - Macular Diseases I: AMD - Week 1

Question 1

True or false
AMD is the most prevalent macular disorder in Australia?

Answer 1

True

Question 2

Is the prevalence of AMD projected to increase or decrease? Explain why.

Answer 2

Increase due to growing elderly population

Question 3

Is AMD a bilateral disease? Explain.

Answer 3

Usually affects one eye, but is a bilateral disease - eventually

Question 4

What do photoreceptors shed? What happends to these and by what?

Answer 4

Shed outer segment discs
RPE enzymes degrade and recycle them

Question 5

What happens to light-damaged elements shed by the photoreceptors? What do they form and what do they coalesce to form?

Answer 5

Light damaged outer segment discs cannot be degraded/recycled.
They form lipofuscin vesicles
These coalesce to form BLamD

Question 6

How can BLamD be visualised?

Answer 6

FAF

Question 7

Where do BLamD accumulate? What happens to them eventually (forming what)?

Answer 7

They accumulate at the basement membrane of the RPE
They are shed by the RPE and form BLinD

Question 8

What are druplets?

Answer 8

BLinD

Question 9

What do druplets coalesce to form?

Answer 9

Drusen

Question 10

Where does reticular drusen form? Is it more or less serious than other forms of drusen?

Answer 10

Forms at the inner surface of the RPE (interface with the photoreceptors)
More serious

Question 11

What keeps the choriocapillaris active and what is it produced by?

Answer 11

Kept active by cytokines produced by the RPE

Question 12

Collectively, what do BLamD, BLinD, and drusen do (2)?

Answer 12

Restrict the RPE, reducing bruch’s membrane flow

Question 13

What is reticular drusen also known as?

Answer 13

Pseudo-drusen

Question 14

What happens to BLinD with age? What happens to bruchs membrane alongside this? What consequence does this have?

Answer 14

It thickens
Bruchs membrane takes up cholesterol from the blood - forms plaques
Further restricts clearance and exchange of RPE

Question 15

Consider what happens to BLinD with age. What happens to the choriocapillaris as a result and what is the consequence of this?

Answer 15

It fails to get PEDF/VEGF and atrophies

Question 16

What promotes an immune response at bruch’s membrane? List two causes of this. Explain how these two result in either wet or dry AMD.

Answer 16

Lack of proper cytokine/metabolite exhcange:
Genotype for factor H
-increases inflammation, resulting in wet AMD
Complement suppression
-decreases inflammation, resulting in dry AMD

Question 17

How do cholesterol plaques affect bruchs membrane’s function?

Answer 17

Cholesterol coats BLinD, which reduces BM hydraulic conductivity

Question 18

What is cholesterol trafficking promoted by and how do genetics of this affect AMD?

Answer 18

Promoted by apo-lipoproteins
People with genetic variants in APoE get faster/worse AMD

Question 19

What does being factor H positive promote?

Answer 19

RPE apoptosis

Question 20

List 5 factors for AMD.

Answer 20

Age
Smoking
Fellow eye with AMD
RPE disruption (RPE disorders)
Genotype for factor H/ApoE

Question 21

Can diet affect AMD risk? Consider carotenoids, antioxidants and fats (2).

Answer 21

Carotenoids and antioxidants confer protection
Saturated fats promote progression
High Omega-3 PUFA confers protection

Question 22

Can high dose antioxidants and/or minerals reduce progression early in AMD or is the eivdence poor?

Answer 22

Reduces progression by 25%

Question 23

In what colour eyes is AMD more common? Give a possible reason why.

Answer 23

More common in blue eyes
-light damage - oxidation

Question 24

What race and gender is more at risk of AMD? Is gender a risk?

Answer 24

Caucasian
Female
-not a risk factor after longevity is considered

Question 25

What proportion of AMD cases are wet and dry?

Answer 25

Wet - 15% Dry - 85%

Question 26

List the four stages of AMD.

Answer 26

1 - druplets and drusen 2 - RPE sress, pigment irregularities Dry - atrophic/non-exudative Wet - exudative

Question 27

What is RPE stress best visualised by? How does it appear?

Answer 27

Fundus autofluorescence (FAF) -appears as dropout zones

Question 28

Can atrophic areas of the RPE develop anywhere in the macula or only specific areas?

Answer 28

Anywhere

Question 29

What is dry AMD characterised by? What kind of vision loss occurs, if any?

Answer 29

Apoptosis of the RPE, giving geographic atrophy Results in slow, very profound vision loss

Question 30

What size of geographic atrophy is clinically significant?

Answer 30

>0.5DD

Question 31

What does the inflammaotry overlay of wet AMD promote (3)? What kind of visiion loss does this result in?

Answer 31

Choroidal neovascularisation (CNVM) Leakage of blood/fluid from CNVM Serous RPE detachment Results in acute profound vision loss

Question 32

What happens to wet AMD over time?

Answer 32

Gives a fibrous scar - disciform degeneration

Question 33

What are the four clinical classifications of AMD based on appearance?

Answer 33

Drusen size (not number) Presence of pigmented abnormality Fellow eye status Other modifying factors

Question 34

Describe how drusen size is classified and note within what distance to the fovea.

Answer 34

Drusen within 2DD of the fovea: Small - druplet <63 microns - <1/4 BV Intermediate - 63 - 125 microns - <1/2 BV Large - >125 microns - size of a vein at the disc

Question 35

How do reticular drusen appear (2)?

Answer 35

Dark craters with a central spot

Question 36

Are reticular drusen high or low risk?

Answer 36

High risk

Question 37

What image is needed to score AMD? Is it for the eye or for the person?

Answer 37

Use colour fundus photography Score is for the person, not the eye Score each drusen within 2DD of the fovea

Question 38

List the scoring for AMD (criteria for each) and the maximum score (5).

Answer 38

Hyper/hypo/disrupted pigment areas >1/4DD Large drusen >125 microns Presence of reticular drusen Presence of bilateral intermediate drusen Presence of end-stage AMD in fellow eye (wet or dry) Each criteria met is 1 score Max score of 4 for any person (R+L)

Question 39

Descibe how to interpret risk scores for AMD.

Answer 39

0 - very low 1 - low 2 - moderate 3 - high 4+ - very high

Question 40

Describe the risk of AMD progression for each risk score.

Answer 40

0 - 0.5% 1 - 3% 2 - 12.5% 3 - 25% 4 - 50% -progression over 5 years, 10 years is similar percentage

Question 41

How should you manage individuals with an AMD risk score of 0 or 1 (2)? Include review schedule.

Answer 41

2 year reviews with CFP/OCT Antioxidants for 1+

Question 42

How should you manage individuals with an AMD risk score of 2 (3)? Include review schedule.

Answer 42

1 year reviews with CFP/OCT Home monitoring Antioxidants for 1+

Question 43

How should you manage individuals with an AMD risk score of 3 (3)? Include review schedule.

Answer 43

6 month reviews with CFP 12/12 and OCT 6/12 Home monitoring Antioxidants for 1+

Question 44

How should you manage individuals with an AMD risk score of 4 (3)? Include review schedule.

Answer 44

3 month reviews with CFP 12/12 and OCT 3/12 Home monitoring Antioxidants for 1+

Question 45

What are 2 options for home monitoring AMD?

Answer 45

Amsler - poor option Tablet/smart phone

Question 46

At what risk score should antioxidant use be promoted?

Answer 46

1+

Question 47

What are patients with iAMD or advanced AMD in one eye recommended to take and why?

Answer 47

AREDS supplements to reduce risk of progression to advanced AMD (25% over 5 years)