AED - Corneal Dystrophies - Week 10 Flashcards
Are corneal dystrophies normally uni- or bilateral?
Bilateral
Are corneal dystrophies fast or sloww progressing?
Slowly progressive
What region of the cornea is typically affected by corneal dystrophy?
Central region
Are corneal dystrophies inflammatory?
Non-inflammatory
Do corneal dystrophies have associated ocular or systemic disease?
No
What is the usual onset for corneal dystrophy?
2nd decade
How many layers do corneal dystrophies primarily involve?
Primarily involves a single corneal layer
List two dystrophies of the corneal epithelium.
Epithelial basement membrane dystrophy
Meesmanns dystrophy
List a dystrophy of bowmans layer.
Reis-bucklers dystrophy
List four dystrophies of the corneal stroma.
Lattice dystrophy
Granular dystrophy
Macular dystrophy
Schnyders crystalline dystrophy
List two dystrophies of the corneal endothelium.
Fuchs dystrophy
Posterior polymorphous dystrophy
Is it easy to classify corneal dystrophies? Explain (2). What complicates this process (2)?
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
What is the most common of all corneal dystrophies? Why is it often misdiagnosed?
Epithelial basement membrane dystrophy
Often misadiagnosed because of its variable appearance
Describe the inheritance of epithelial basement membrane dystrophy (2).
Many cases have no inheritance documented
Some autosomal dominant familial cases
What is the onset of epithelial basement membrane dystrophy? Is it common in children?
Usually adulthood
Rarely observed in children
What is the pathology of epithelial basement membrane dystrophy (list the cause and what this results in)
Abnormal maturation, production, and turnover of the basement membrane, leading to poor epithelial attachment.
Describe the signs of epithelial basement membrane dystrophy collectively known as ‘maps’ (shape, colour, appearance, edge).
Irregular islands of thickened, grey, hazy epithelium with scalloped edges
Describe the signs of epithelial basement membrane dystrophy collectively known as ‘dots’ (shape, colour, appearance).
Irregular, round or comma-shaped, non-staining, grey opacities
Describe the signs of epithelial basement membrane dystrophy collectively known as ‘fingerprints’. What slit lamp thechnique is best for viewing this?
Parallel, curvilinear lines, paracentral
Best seen with retroillumination
What does negative staining indicate, and how does it relate to epithelial basement membrane dystrophy?
Areas of elevated epithelium
Is a sign of epithelial basement membrane dystrophy
List 4 symptoms of epithelial basement membrane dystrophy. What causes these to manifest?
Asymptomatic but can have periodic:
Mild blurred visiond
Image ghosting
Irritation
Occurs as cysts rupture
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.
Recurrent corneal erosion, increasing incidence with age
Pain
FB sensation with specific onset
Potatophobia
Decreased vision
List 2 signs of epithelial basement membrane dystrophy.
Epithelial microcysts can rupture from time to time
Results in SPK and irritation
What is the assessment for epithelial basement membrane dystrophy (3)?
History and careful slit lamp with fluorescein
What is the management for epithelial basement membrane dystrophy (3)?
Lubricants
Management of co-existing surface diseases if symptomatic
Treat RCE if required
Is meesmanns dystrophy common or rare?
Very rare
What is the mode of inheritance for meesmans dystrophy?
Autosomal dominant
What is the onset for meesmanns dystrophy? Is it rapid or slow progressing?
Early childhood and slowly progressive
At what age do symptoms of meesmans dystrophy typically manifest?
Fourth decade
What is the pathology of meesmanns dystrophy?
Due to a mutation in keratin genes
List 4 symptoms of meesmans dystrophy.
Transient blurred vision
Surface irritation
Mild FB sensation
Photophobia
List a sign of meesmanns dystrophy (number, size, layer, region).
Multiple, tiny intra-epithelial vesicles (cysts) extending to the limbus
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
What is the treatment for meesmanns dystrophy (2)?
Surface lubrication
Bandage contact lenses
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
What is the mode of inheritance for reis-bucklers dystrophy?
Autosomal dominant
What is the onset for reis-bucklers dystrophy?
Childhood
List 5 symptoms of reis-bucklers dystrophy.
Red/sore eyes
Photophobia
Watery eyes
Ocular surface discomfort
Increasing blurred vision with age
What happens to vision over time with reis-bucklers dystrophy? Explain why.
Blurs
The modified bowmans layer thickens over time
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
List a sign of reis-bucklers dystrophy.
Slowly progressive deterioration of vision
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
What is the management for reis-bucklers dystrophy (2)?
Manage RCEs as required
Monitor for decreased vision
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
Is it common for reis-bucklers dystrophy to recur following surgical intervention?
Yesd
Is thiel-behnke corneal dystrophy common or rare? What is the mode of inheritance?
Very rare
Autosomal dominant
What is the onset for thiel-behnke corneal dystrophy?
Late childhood
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
List a sign of thiel-behnke corneal dystrophy.
Symmetrical, sub-epithelial, reticular opacities (honeycomb-like)
What is the management for thiel-behnke corneal dystrophy?
As per reid-bucklers dystrophy