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Introduction to Eye Disease - Year 2 > AMD > Flashcards

AMD Flashcards

1
Q

What is AMD?

A

Age Related Macula Degeneration - this is a degenerative disorder of the macula causing significant visual loss

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2
Q

Why are we so interested in AMD?

A

Leading cause of irreversible visual impairment in the Western World (Bourne et al., 2013)

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3
Q

What are the two types of AMD?

A

Dry and Wet AMD

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4
Q

What may dry AMD also be referred to as?

A

Atrophic/non-neovascular AMD

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5
Q

What may wet AMD also be referred to as?

A

Neovascular/exudative AMD

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6
Q

Which type of AMD is more common - dry or wet?

A

Dry AMD - it accounts for 90% of cases

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7
Q

What are the early signs of dry AMD ?

A
  • Drusen ≥63µm
  • RPE (retinal pigment epithelium) hyper/hypo pigmentation
  • RPE (retinal pigment epithelium) atrophy
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8
Q

What are the late signs of dry AMD?

A

Geographic atrophy - sharply demarcted areas of atrophy (i.e. when the center portion of the vision, the macula, starts to lose the actual cells in the retinal layers. )

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9
Q

What are the signs of wet AMD?

A
  • Choroidal neovascularisation (CNV) which can lead to scarring (disciform)
  • Macular oedema
  • Sub retinal fluid (SRF) - which is a Serous detachment of neurosensory retina
  • RPE detachment (also known as a PED) or a tear of the RPE
  • Haemorrhages – these can be Sub, intra or pre retinal
  • Exudates

Also includes:

  • Retinal angiomatous proliferation (RAP)
  • Polypoidal choroidal vasculopathy (PCV)
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10
Q

What are the classifications/ degrees of AMD?

A
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11
Q

What is pathogenesis?

A

The manner of development of a disease

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12
Q

What is the first sign of dry AMD?

What is a disadvantage of using this as a diagnosing factor for AMD?

A

Basal Laminar Deposits - these are lipid deposits in Bruch’s membrane (which occur as a result of failure of the RPE to process cell debris).

They are only present in histology (histopathology) i.e. you can only view these on a microscope as a slide from someones eye (not via a direct ophthalmoscopy or otherwise) ( it is highlighted in the picture by the red circle).

[This sign is used as a histopathological marker for AMD)

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13
Q

What is the difference between druse and drusen?

A
  • Plural = drusen
  • single = druse
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14
Q

What is the first clinically visible sign of dry AMD?

A

Drusen

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15
Q

What are drusen?

A
  • Extracellular deposits between RPE and Bruch’s memebrane
  • Derived from immune mediated and metabolic processes in RPE, consist of Lipofuscin, amyloid, complement factors
  • [These are age-related and common in 60+ px]
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16
Q

What are the different types of drusen?

A

Hard and soft drusen

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17
Q

What are the clinical features to consider when looking at drusen?

A

Its size:

  • Small ( in which case the type is hard) ≤63µm
  • Intermediate 63-125µm
  • Large >125µm

The type of drusen:

  • i.e. whether it is hard , soft or confluent (meaning a merge of both)?

Whether it is asscoiated with any pigmentary changes e.g. hypo or hyper-pigmentation.

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18
Q

What are the yellow specs in the image shown?

A

Small hard drusen

[These are not only limited to the macula region but the periphery too]

19
Q

What are the yellow specs in the image below?

A

Intermediate (bc of their size) Soft (bc of the blurred circel margins) drusen

20
Q

What can be seen in the blue circle (2)?

A

Confluent drusen - when this is present you will be able to see both soft and hard drusen and then areas where they are merging.

In the blue cirle RPE chnages can also be seen.

21
Q

If both drusen and RPE chnage scan be seen what is the patient t risk of developing?

A

Adanced / Late (dry) AMD

22
Q

What RPE changes can be see circled in blue (2)?

Therefore is this a sign of early or late , dry or wet AMD?

A

Hyperpigmentation

Pigment clumping

Early Dry AMD

23
Q

What happens in geographical atrophy?

A

We experience a loss of RPE cells which causes unmasking of choroidal blood vessels

24
Q

What can be seen highlighted in one of the circles?

Is this early or late , dry or wet AMD?

A

In the yellow circle - unmasking of choroidal blood vessels can be seen (as a result of geogrpahical atrophy) , areas of hypopigmentation

In the blue circle - Drusen

Black circle - RPE chnages - hyperpigmentation , hypopigmentation.

25
Q

True or false- patients with late AMD in 1 eye have about a 50% chance of developing advanced AMD in fellow eye within 5 years.

A

True

26
Q

Can an eye progress from wet AMD to wet AMD ?

A

Yes - in fact the chance of this happening increases depending on the symptoms experienced by the patient.

27
Q

What is the pathogenesis of wet AMD?

A
  • Initially there is a thickening of Bruch’s membrane
  • (which involves an increase in advance glycation end (AGEs) products
  • And an increase in lipids and exogenous proteins)
  • This creates a hydrophobic barrier between the choroid and retina
  • Which leads to Ischaemia
  • In response to this ischaemia there is a release of Vascular Endothelial Growth Factor (VEGF)
  • This leads to Neovascularisation from choriocapillaris via breaks in Bruch’s membrane
  • New vessels from choriocapillaris penetrate RPE
  • Situated beneath neurosensory retina
  • New vessels are “leaky” in nature and as a result we may see exudates
  • As well as Sub-retinal haemorrhages- if new blood vessels leak.
  • All this activity together can lead to the formation of a Choroidal Neovascular membrane (CNV membrane)
  • Sub-retinal Fluid may be present between the RPE layer and retina – it enters through damaged pigment epithelium.
  • All this activity together may cause Retinal Pigment Epithelium Detachment (this is referred to as RPED or PED).
28
Q

What can be seen in this OCT scan?

A

PED - pigment epithelium detachment - detachment of RPE from inner collagenous layer of Bruch’s membrane.

29
Q

What different types of PED can there be?

A

Serous PED – this is characterised by an orange dome shaped elevation with clearly defined edges.

Fibrovascular PED – this is characterised by a much more irregular detachment

Drusenooid PED – this is characterised by a shallower detachment, developed from confluent large drusen

30
Q

How does a Choroidal neovascular membrane present on fundus photography?

A

As a gree tinge

31
Q

What clinical skills are being highlighted by the yellow arrows?

What type of AMD does this px have?

A

Wet AMD

32
Q

What is a sub-retinal haemorrhage?

How do we know that the image below is a sub-retinal haemorrhage?

A

When bleeding occurs into the sub-retinal space.

Because the overlying blood vessels are still vissible - look at the lighter parts of the haemorrhage (circled in blue) to see those overlying blood vessels.

33
Q

What is being shown in the OCT scan via the red arrow?

A

A choroidal neovascular membrane (CNV).

34
Q

What is the prevalence of late AMD?

A
35
Q

What are risk factors for wet AMD?

A
36
Q

What is an amsler grid test?

A

A simple eye test done to detect problems in vision due to macular degeneration.

Where px views the following grid:

37
Q

How does AMD affect vision?

A

Px will experience central blurring (periphery is all good).

Px will also experience distrotion of straight lines - so they will appear wobbly.

38
Q

What are the symptoms of wet and dry AMD?

A
39
Q

What are the diagnostic tools that can be used to diagnose AMD?

A
  • BCVA – EDTRS chart
  • Amsler Test
  • Assessing Reading speed
  • Microperimetry – perimetry for the central area
  • Fundus BIO
  • OCT scans
  • FAF – fundus autofluorescence
  • FA – fluorescein angiography
  • Multifocal ERG ( this is used as a research tool)
40
Q

What is the optoetric management of Dry AMD?

A
  • Giving the Px information ( + reassurance)
  • Some px may need low vision aids ( to provide high magnification to help at near - equally you may consider prescribing high ADDs)
  • Give Prevention advice
41
Q

What is the optometric management of wet AMD?

A
  • Urgent referral if VA >6/96
  • VA <6/96 not urgent referral
  • As advanced AMD is an untreatable disease characterised by sub-retinal fibrosis and/or pigmentary changes

•

•Direct referral to specialist macular clinic

42
Q

What are the preventative measures for AMD?

A

•STOP SMOKING!

•

•

  • Anti-oxidant supplements [In Px with advanced AMD in 1 eye, risk of progression to advanced AMD reduced by 25% through suppliments}
  • Supliments such as Macular carotenoids

•

  • Diet - a good diet is key
  • Treatment of any risk factors
43
Q

What is the ophthalmic management of AMD?

A

Introduction to Eye Disease - Year 2 (40 decks)

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