AED - Corneal Dystrophies - Week 10 Flashcards
1
Q
Are corneal dystrophies normally uni- or bilateral?
A
Bilateral
2
Q
Are corneal dystrophies fast or sloww progressing?
A
Slowly progressive
3
Q
What region of the cornea is typically affected by corneal dystrophy?
A
Central region
4
Q
Are corneal dystrophies inflammatory?
A
Non-inflammatory
5
Q
Do corneal dystrophies have associated ocular or systemic disease?
A
No
6
Q
What is the usual onset for corneal dystrophy?
A
2nd decade
7
Q
How many layers do corneal dystrophies primarily involve?
A
Primarily involves a single corneal layer
8
Q
List two dystrophies of the corneal epithelium.
A
Epithelial basement membrane dystrophy
Meesmanns dystrophy
9
Q
List a dystrophy of bowmans layer.
A
Reis-bucklers dystrophy
10
Q
List four dystrophies of the corneal stroma.
A
Lattice dystrophy
Granular dystrophy
Macular dystrophy
Schnyders crystalline dystrophy
11
Q
List two dystrophies of the corneal endothelium.
A
Fuchs dystrophy
Posterior polymorphous dystrophy
12
Q
Is it easy to classify corneal dystrophies? Explain (2). What complicates this process (2)?
A
It is difficult dut to their relative rarity and heterogenous clinical appearance
Complicated by studies showing ‘distinct’ dystrophies are mutations in the same gene
Also individual dystrophies encompass mutations on completely different genes
13
Q
What is the most common of all corneal dystrophies? Why is it often misdiagnosed?
A
Epithelial basement membrane dystrophy
Often misadiagnosed because of its variable appearance
14
Q
Describe the inheritance of epithelial basement membrane dystrophy (2).
A
Many cases have no inheritance documented
Some autosomal dominant familial cases
15
Q
What is the onset of epithelial basement membrane dystrophy? Is it common in children?
A
Usually adulthood
Rarely observed in children
16
Q
What is the pathology of epithelial basement membrane dystrophy (list the cause and what this results in)
A
Abnormal maturation, production, and turnover of the basement membrane, leading to poor epithelial attachment.
17
Q
Describe the signs of epithelial basement membrane dystrophy collectively known as ‘maps’ (shape, colour, appearance, edge).
A
Irregular islands of thickened, grey, hazy epithelium with scalloped edges
18
Q
Describe the signs of epithelial basement membrane dystrophy collectively known as ‘dots’ (shape, colour, appearance).
A
Irregular, round or comma-shaped, non-staining, grey opacities
19
Q
Describe the signs of epithelial basement membrane dystrophy collectively known as ‘fingerprints’. What slit lamp thechnique is best for viewing this?
A
Parallel, curvilinear lines, paracentral
Best seen with retroillumination
20
Q
What does negative staining indicate, and how does it relate to epithelial basement membrane dystrophy?
A
Areas of elevated epithelium
Is a sign of epithelial basement membrane dystrophy
21
Q
List 4 symptoms of epithelial basement membrane dystrophy. What causes these to manifest?
A
Asymptomatic but can have periodic: Mild blurred visiond Image ghosting Irritation Occurs as cysts rupture
22
Q
Consider the cause of symptoms of epithelial basement membrane dystrophy. What can occur in ~10% of patients and what does the risk of this increase with? List 5 symptoms of this.
A
Recurrent corneal erosion, increasing incidence with age Pain FB sensation with specific onset Potatophobia Decreased vision
23
Q
List 2 signs of epithelial basement membrane dystrophy.
A
Epithelial microcysts can rupture from time to time
Results in SPK and irritation
24
Q
What is the assessment for epithelial basement membrane dystrophy (3)?
A
History and careful slit lamp with fluorescein
25
What is the management for epithelial basement membrane dystrophy (3)?
Lubricants
Management of co-existing surface diseases if symptomatic
Treat RCE if required
26
Is meesmanns dystrophy common or rare?
Very rare
27
What is the mode of inheritance for meesmans dystrophy?
Autosomal dominant
28
What is the onset for meesmanns dystrophy? Is it rapid or slow progressing?
Early childhood and slowly progressive
29
At what age do symptoms of meesmans dystrophy typically manifest?
Fourth decade
30
What is the pathology of meesmanns dystrophy?
Due to a mutation in keratin genes
31
List 4 symptoms of meesmans dystrophy.
Transient blurred vision
Surface irritation
Mild FB sensation
Photophobia
32
List a sign of meesmanns dystrophy (number, size, layer, region).
Multiple, tiny intra-epithelial vesicles (cysts) extending to the limbus
33
Where are lesions of meesmans dystrophy most common? What slit lamp technique is best to visualise them?
Most numerous in the intra-palpebral area
| Best seen in retro-illumination
34
What is the treatment for meesmanns dystrophy (2)?
Surface lubrication
| Bandage contact lenses
35
What layer does reis-bucklers dystrophy affect and what is this layer replaced with? Is it common or rare?
Affects bowmans layer
| Replaced by a sheet-like connective tissue layer
36
What is the mode of inheritance for reis-bucklers dystrophy?
Autosomal dominant
37
What is the onset for reis-bucklers dystrophy?
Childhood
38
List 5 symptoms of reis-bucklers dystrophy.
```
Red/sore eyes
Photophobia
Watery eyes
Ocular surface discomfort
Increasing blurred vision with age
```
39
What happens to vision over time with reis-bucklers dystrophy? Explain why.
Blurs
| The modified bowmans layer thickens over time
40
What type collagen does bowmans layer normally have and how are fibres arranged? What happens with reis-bucklers dystrophy?
Type I collagen arranged randomly with pores for nerves
| In reis-bucklers dystrophy, the layer is obliterated and replaced by randomly arranged collagen that thickens over time
41
List a sign of reis-bucklers dystrophy.
Slowly progressive deterioration of vision
42
How does reis-bucklers dystrophy appear early on? What about later into the disease?
Early childhood - fine, patchy supepithelial opacities
| Late stage - polycystic pattern extending to the mid periphery
43
What is the management for reis-bucklers dystrophy (2)?
Manage RCEs as required
| Monitor for decreased vision
44
Around what time is surgical intervention necessary for reis-bucklers dystrophy? List two surgery options.
Usually needed by the fifth decade
Refer for superficial keratectomy or PTK
May require keratoplasty
45
Is it common for reis-bucklers dystrophy to recur following surgical intervention?
Yesd
46
Is thiel-behnke corneal dystrophy common or rare? What is the mode of inheritance?
Very rare
| Autosomal dominant
47
What is the onset for thiel-behnke corneal dystrophy?
Late childhood
48
List 4 symptoms of thiel-behnke corneal dystrophy. What other dystrophy is it similar to? How can they be distinguished by symptoms?
Red/sore eyes
Photophobia
Ocular surface discomfort
Increasing blurred bision with age
Very similar (possible variant) of reis-bucklers dystrophy
Blurred vision occurs later than in reis-bucklers dystrophy
49
List a sign of thiel-behnke corneal dystrophy.
Symmetrical, sub-epithelial, reticular opacities (honeycomb-like)
50
What is the management for thiel-behnke corneal dystrophy?
As per reid-bucklers dystrophy
51
What is the most common stromal dystrophy?
Lattice dystrophy
52
What is lattice dystrophy caused by?
Amyloid deposits at different levels within the stroma
53
What is the mode of inheritance for lattice dystrophy? How many variants of lattice dystrophy is there?
Autosomal dominant
| 4 variants
54
What is the onset of lattice dystrophy?
Variable
55
List two signs of lattice dystrophy.
Decreased corneal sensation
| Reduced visual acuity over time
56
What does lattice dystrophy look like?
Lattice-like corneal folds within the cornea - similar to gonio folds, but lattice pattern
57
List 5 symptoms of lattice dystrophy.
```
Ocular discomfort
Photophobia
Blurred vision
RCE
Visual impairment over time
```
58
Do all variants of lattice dystrophy share the same mode of inheritance?
Yesd autosomal dominant
59
Distinguish type II lattice dystrophy from type I (3).
Lattice lines are thicker, but less numerous (in type II)
Lines begin peripherally and extend centrally
Later onset vs type I
60
What is a differential diagnosis for lattice dystrophy?
Polymorphic amyloid degneration
61
What is the treatment for lattice degeneration (2)?
Monitor closely and manage RCE/discomfort
| Refer if vision is significantly reduced for PTK
62
What does success of surgical intervention for lattice dystrophy depend on? What may some forms require? Is recurrence possible? Compare to reis-bucklers dystrophy.
Depends on the depth of lines
Some forms may require lamellar graft or penetrating keratoplasty
Recurrence of dystrophy possible, but takes longer than reis-bucklers dystrophy
63
Is granular dystrophy common or rare?
very rare
64
What is granular dystrophy caused by? What is the mode of inheritance and onset?
Caused by hyaline deposits at different levels within the stroma
Autosomal dominant
Childhood onset
65
What region of the eye does granular dystrophy appear initially and what does it look like? What can happen to them and what happens to them eventually (layer)?
Initially central, with a crumb-like opaque appearance
Can coalesce
Eventually involves deeper stroma
66
What does the area between lesions of granular dystrophy have the appearance of?
Ground glass
67
List a differential diagnosis for granular dystrophy and give two examples.
Other anterior stromal dystrophies
- reis-bucklers dystrophy
- macular dystrophy
68
What is the treatment for granular dystrophy (4)?
Early on - lubricants
| With time, bandage contact lenses, superficial keratecomy/PTK and keratoplasty
69
What two dystrophies is avellino dystrophy a variant of? What is it characterised by (layer and lattice appearance)?
Variant of granular and lattice dystrophies
| Characterised by granular deposits in the anterior stroma and deeper lattice lines
70
What is the cause of avellino dystrophy (2)?
Deposition of both amyloid and hyaline in the corneal stroma
71
Who can many patients with avellino dystrophy trace their ancestry back to? Is this clinical profile exclusive to them?
Avellino in italy, but clinical profile may not be exclusive
72
Is avellino dystrophy common or rare? what is the mode of inheritance and what onset?
Rare
Autosomal dominant
Usually 1st or 2nd decades
73
How does avellino dystrophy appear (general shapes)?
Icicle.star-shaped stromal opacities among disk-shaped opacities
74
List 3 symptoms of avellino dystrophy.
Pain
Recurrent corneal erosion
Reduced vision
75
Give a differential diagnosis for avellino dystrophy. Give three examples.
Other anterior stromal dystrophies
Reis-bucklers dystrophy
Granular dystrophy
Lattice dystrophy
76
What is the treatment for avellino dystrophy?
As for other stromal dystrophies
77
What is the least common stromal dystrophy?
Macular dystrophy
78
What is the most severe stromal dystrophy?
Macular dystrophy
79
What is macular dystrophy caused by?
Glycosaminoglycan deposits
80
What is the mode f inheritance for macular dystrophy?
Autosomal recessive
81
Which region is macular dystrophy more common?
Middle East
82
What are the two subtypes of macular dystrophy and how is this achieved? Which is more common and what is the onset?
Typed through blood testing
Type I and II
Type I onset is in childhood and is more common
83
Distinguish between type I and II macular dystrophy.
Type I lacks keratan sulphate in the cornea
| Type II - keratan sulphates are present in the cornea
84
How does macular dystrophy appear (region, colour, edge)? From where to where does it extend?
Central, grey-white, ill-defined but focal opacities
| Extends from limbus to limbus
85
Can macular dystrophy involve the entire stromal thickness?
Yesd eventually
86
List 3 signs of macular dystrophy.
Reduced corneal thickness
Reduced corneal sensitivity
Corneal endothelium affected in late disease (guttatae)
87
List a differential diagnosis for macular dystrophy and give three examples.
Other anterior stromal dystrophies
Reis-bucklers dystrophy
Granular dystrophy
Lattice dystrophy
88
What is the treatment for macular dystrophy? Is recirrence common?
Referral for penetrating keratoplasty
| Recurrence uncommon
89
By when is vision significantly affected in macular dystrophy?
Third decade
90
Is schnyders corneal dystrophy common or rare? What is the mode of inheritance and onset?
Rare
Autosomal dominant
Onset 2nd or 3rd decade
91
What condition may schnyders corneal dystrophy be associated with?
Systemic hypercholesterolaemia
92
In what form of schnyders corneal dystrophy is diagnosis more difficult?
Acrystalline form
93
What is schnyders corneal dystrophy caused by? What defect in what cell and what this leads to (2)?
Caused by a metabolic defect in corneal keratocytes, leading to cholesterol deposition in the anterior stroma
94
What does schnyders corneal dystrophy look like (colour, region, layer)?
White-yellow lipid deposits in the central anterior stroma
95
What is schnyders corneal dystrophy often associated with (ocular and not systemic)?
Prominent corneal arcus
96
List two symptoms of schnyders corneal dystrophy.
Increasing glare and reduced visiond in adulthood
97
List two differential diagnoses for schnyders corneal dystrophy and give three examples for each.
```
Other anterior stromal dystrophy
-reis-bucklers dystrophy
-granular dystrophy
-lattice dystrophy
Other causes of corneal crystals
-infectious crystalline keratopathy
-gout
-mutiple myeloma
```
98
What is the treatment for schnyders corneal dystrophy (2)?
Refer for blood lipid workup
| Referral for PTK in patients with severe glare
99
Is a corneal graft typically required for schnyders corneal dystrophy?
Rarely
100
What is the most common endothelial dystrophy?
Fuchs endothelial corneal dystrophy
101
Which gender is more affected by fuchs endothelial corneal dystrophy?
Females>males
102
Are cases withot inheritance common for fuchs endothelial corneal dystrophy? What is the mode of inheritance (2)?
Cases without inheritance most common
Autosomal dominant
Can be autosomal recessive
103
When is fuchs endothelial corneal dystrophy typically symptomatic?
5th decade
104
What is fuchs endothelial corneal dystrophy due to and what happens to endothelial cells as a result? What develops on descemets membrane and what is this called? What is the ultimate consequence of these events?
Due to diffuse thickening and lamination of descemets membrane
Endothelial cells become sparse and atrophic
Development of hyaline excrescences on the thickened membrane - corneal guttata
Progressive degeneration of corneal endothelial cells
105
Is fuchs endothelial corneal dystrophy symptomatic early on?
Not typically
106
List a symptom of moderate fuchs endothelial corneal dystrophy and why it occurs.
Mild decrease in VA which increases over time as the posterior stromal oedema increases
107
List a symptom of late fuchs endothelial corneal dystrophy and why it occurs. When is it worse (time of the day)? Does it improve?
Significant reduction in VA due to epithelial oedema
| Worse upon waking, which improves after several hours
108
What may patients with late fuchs endothelial corneal dystrophy develop? What can this cause and why?
Epithelial bullae which can rupture, causing severe pain
109
What two lesions can be seen with fuchs endothelial corneal dystrophy?
Epithelial microcysts and bullae
110
List three differential diagnoses for fuchs endothelial corneal dystrophy.
Aphakic and pseudophakic bullous keratopathy (after cataract surgery)
Posterior polymorphous dystrophy
111
When is a review for fuchs endothelial corneal dystrophy recommended?
6/12 months
112
What are the three components to working up fuchs endothelial corneal dystrophy?
Pachymetry
Specular microscopy
IOP
113
What are two treatment options for corneal oedema with fuchs endothelial corneal dystrophy?
```
Hypertonic solution (5%)
Warm hairdryer over cornea upon waking
```
114
What are two treatment options for bullae with fuchs endothelial corneal dystrophy?
Ocular lubricants
| Bandage CLs
115
What will eventually be required for fuchs endothelial corneal dystrophy (treatment)?
Referra for penetrating keratoplasty
116
What two layers are affected in posterior polymorphous corneal dystrophy?
Descemets membrane and the endothelium
117
What is the mode of inhertiance and onset for posterior polymorphous corneal dystrophy?
Autosomal dominant
| Early childhood
118
What appearance do corneal endothelial cells have with posterior polymorphous corneal dystrophy? What structure do they have and what do they stain positive for?
Appearance of epithelial cells
| Have microvilli and stain for keratin
119
What does posterior polymorphous corneal dystrophy increase the risk of and why?
Increased risk of glaucoma due to cells growing into the trabecular meshwork
120
What condition may posterior polymorphous corneal dystrophy be associated with?
Alports syndrome
121
How do the lesions of posterior polymorphous corneal dystrophy appear? Are they symmetric?
Grouped or linear bubble-like lesions within descemets membrane
Lesions are frequently asymmetric
122
What may develop in advanced cases of posterior polymorphous corneal dystrophy?
Corneal oedema
123
What can develop in ~25% of posterior polymorphous corneal dystrophy cases?
Peripheral irido-corneal adhesions
124
Are symptoms of posterior polymorphous corneal dystrophy common? List 2 of them.
Uncommon
| May develop reduced vision and ocular discomfort if corneal oedema develops
125
List 2 differential diagnoses for posterior polymorphous corneal dystrophy. Explain differentiating factors for each if applicable.
Iridocorneal endothelial syndrome (unilateral, non-hereditary)
Fuchs endothelial dystrophy (late onset)
126
What is the treatment for posterior polymorphous corneal dystrophy (3)?
Most dont require treatment for corneal changes
Must monitor IOP each visit
If treatment required, as per fuchs endothelial dystrophy
