CLM - Pathological Changes in High Myopia - Week 7 Flashcards

1
Q

List the power ranges (huhuhu) associated with the 3 categorical classifications of myopia.

A

Low - <3.00D
Medium/moderate - -3.00 to -5.75D
High - ≥-6.00D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define pathological myopia.

A

Myopia associated with characterisic degenerative changes in the sclera, choroid and RPE, in association with compromised visual function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the prevalence of high myopia in Australia?

A

2%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List 4 myopia associated pathologies.

A

Retinal abnormalities
-macula
-peripheral
Optic disc pathologies
Scleral abnormalities
Other (cataract)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the most common complication of high myopia?

A

Myopic maculopathy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define myopic maculopathy. List 4 signs.

A

Slow prograssive atrophy of the macula
-lacquer cracks
-choroidal neovascularisation
-macular holes
-macular retinochisis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is myopic maculopathy sight-treatening?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the cause of myopic maculopathy (3)?

A

Not certain but believed excessive elongation thins retina and choroid + weakened sclera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In what percentage of myopic eyes does myopic maculopathy progress significantly?

A

40%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are lacquer cracks in myopic maculopathy?

A

Spontaneous ruptures in the elastic layer of bruch’s membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Are lacquer cracks symptomatic or asymptomatic?

A

Initially asymptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do lacquer cracks appear in colour and at the border?

A

Fine, irregular, yellow lines
Mottled pigment at the border

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a sudden decrease in VA often associated with in high myopic eyes?

A

Sub-retinal haemorrhage due to myopic choroidal neovascularisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In what percentage of high myopic eyes does choroidal neovacularisation occur?

A

10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the cause of choroidal neovascularisation?

A

Due to growth of new blood vessels from the choroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Does choroidal neovascularisation have a good or poor prognosis?

A

Very poor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is macular retinoschisis?

A

Splitting of the neural retina into its inner and outer layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What two effects does macular retinoschisis have on vision?

A

Visual distortion and metamorphopsia

19
Q

What does macular retinoschisis precede?

A

The formation of a true macular hole

20
Q

In what percentage of high myopic eyes does macular retinoschisis progress to a true retinal detachment?

A

20-50%

21
Q

What can retinal detachment develop secondary to?

A

A retinal hole (macula hole)

22
Q

What are macular holes common in eyes with?

A

Posterior staphyloma

23
Q

What is the most important peripheral retinal abnormality in high myopic eyes?

A

Lattice degeneration

24
Q

What size can lattice degeneration have?

A

0.5 - 6 DDs

25
Q

How does lattice degeneration appear?

A

White criss-crossed lines

26
Q

What causes lattice degeneration?

A

RPE hyperplasia

27
Q

What can vessels be surrounded by in lattice degeneration?

A

Glial proliferation

28
Q

What is lattice degeneration accompanied by (2)?

A

Areas of vitreo-retinal adhesion and retinal thinning

29
Q

In what percentage of high myopic eyes is lattice degeneration found?

A

10%

30
Q

What is the long-term risk of retinal detachment if lattice degeneration is present?

A

0.5%

31
Q

What is rhegmatogenous retinal detachment?

A

Separation of the retina due to a break in the sensory retina

32
Q

Is glaucoma associated with a higher or lower risk of primary open angle glaucoma? Explain why in terms of how glaucoma affects the eye.

A

Higher risk (approximately double)
Longer axial length -> greater deformation of the lamina cribrosa

33
Q

What is posterior staphyloma and why does it occur?

A

Bulging due to extasia of the globe, as a consequence of excessive axial elongation

34
Q

What does posterior staphyloma involve regarding the layers of the eye?

A

Outward protrusion of all the layers of the eye

35
Q

What does recent data suggest of collagen bundles in the posterior poles in posterior staphyloma?

A

They may be abbnormal leading to a loss of structural integrity

36
Q

What does posterior staphyloma predispose one to?

A

Other pathologies like macular holes and foveoshisis

37
Q

What is scleral thickness like in high myopic eyes (what layer is affected specifically)?

A

Thinner, has a much thinner stroma

38
Q

List 7 architectural differences of scleral bundles in the sclera of high myopic eyes.

A

Loss of longitudinal striations
Dissociation of bundles from each other
Reduced number of lamellae
Thinning of lamellae
Loose/irregular fibre arrangement
Reduced number of cells and melanocytes
Reduced scleral fibril diameter

39
Q

Overall, how does a myopic sclera compare to an emmetropic sclera in strength?

A

It is weaker

40
Q

Is there an association between myopia and cataract (be specific)?

A

Yes, posterior sub-capsular cataract
Axial length may be the root cause

41
Q

Does myopia correction prevent resultant myopic pathology?

A

No

42
Q

Does laser refractive surgery treat the structural causes of myopia?

A

No

43
Q

Are eyes still at risk of myopia-associated pathologies?

A

Yes