35. Corneal Dystrophies Flashcards
What are the 9 main features of corneal dystrophy?
- Inherited ~50% autosomal dominant
- Bilateral, but may be asymmetric
- Slowly progressive: accumulation of deposits
- Central
- Non-inflammatory
- No associated systemic or ocular disease
- Central location
- Early onset ~2nd decade
- Primary involve in a single corneal layer
Categorise the 9 different corneal dystrophies according to the layers that they affect.
Epithelial
* Epithelial basement membrane dystrophy (EBMD)
* Meesmann’s dystrophy
Bowman’s
* Reis-Buckler’s dystrophy
Stromal
* Lattice dystrophy
* Granular dystrophy
* Macular dystrophy
* Schnyder’s crystalline dystrophy
Endothelial
* Fuch’s dystrophy
* Posterior polymorphous dystrophy
Do px with the same genetic abnormality present with the same corneal dystrophies?
No, px with the same genetic abnormality can have a very different/ heterogenous clinical phenotype. Individual dystrophies encompasses mutations on completely different genes although some may appear similar.
... (EBMD) is also known as ... microcystic dystrophy, ... dystrophy, and ... dystrophy. This is the ... of all corneal dystrophies. It is often misdiagnosed due to its ... appearance. Many cases do not have ... but some may have ... familial cases. The onset of EBMD is usually .... This is thought to be caused by abnormal ..., production and ... of ... leading to poor ... and ....
Epithelial Basement Membrane Dystrophy (EBMD) is also known as Cogan's microcystic dystrophy, Map-dot-fingerprint dystrophy, and anterior basement mebrane dystrophy. This is the most common of all corneal dystrophies. It is often misdiagnosed due to its variable appearance. Many cases do not have inheritance but some may have autosomal dominant familial cases. The onset of EBMD is usually adulthood. This is thought to be caused by abnormal maturation, production and turnover of basement membrane leading to poor epithelial attachment and intraepithelial debris.
What are the 5 clinical signs of EBMD?
- Maps = irregular islands of thickened, grey, hazy epithelium with scalloped edges
- Dots = irregular round or comma-shaped, non-staining, grey opacities
- Fingerprints = parallel, curvilinear lines, usually paracentral; best seen in retroillumination
- Negative staining due to elevated areas of epithelium
- Epithelial microcysts - can rupture from time to time & appear as SPK & irritation
What are the symptoms of EBMD?
- Px are usually asymptomatic but can have periodic, mild, blurred vision, image ghosting and irritation as cysts rupture
- Recurrent corneal erosions develop in 10% of px - causing pain, FB sensation, photophobia, decrease vision
Meesman’s dystrophy is also known as ... dystrophy and ... dystrophy. It is very rare and it is has an ... inheritance. It’s onset is usually ... and .... This is due to mutation in ... geens (... and ... genes of chromosomes 12q13 and 17q12 respectively).Clinical signs include multiple... that contain period ... peculiar substance. These extend to the ... and is most numerous in the ... area.
Px symptoms include:
* Transient ...
* ...
* Mild ... with ... possible with progressive disease
Meesman’s dystrophy is also known as Stocker-Holt dystrophy and Juvenile hereditary epithelial dystrophy. It is very rare and it is has an autosomal dominant inheritance. It’s onset is usually early childhood and slowly progressive. This is due to mutation in keratin geens (K3 and K12 genes of chromosomes 12q13 and 17q12 respectively).
Clinical signs include multipleintra-epithelial vesicles/ cysts that contain period acid-Schiff-positive peculiar substance. These extend to the limbus and is most numerous in the intra-palpebral area.
Px symptoms include:
* Transient blurred vision
* Surface irritation
* Mild FB sensation with photophobia possible with progressive disease
What are the treatments of Meesman’s dystrophy?
- Surface lubrication e.g. Hyloforte QID
- Bandage CL
Reis-Buckler’s dystrophy affects the ... and replace the typically transparent layer with ... that is ..., causing an ... looking .... This is very rare and has an ... inheritance. This has significant symptomatic onset in ....
Px symptoms include:
* ..., sore eyes
* ..., watery eyes, ...
* Ocular surface discomfort
* Increasing ... with age (vision impaired from ...)
Reis-Buckler’s dystrophy affects the Bowman's layer and replace the typically transparent layer with collagen that is regularly arranged, causing an opaque looking Bowman's layer. This is very rare and has an autosomal dominant inheritance. This has significant symptomatic onset in childhood.
Px symptoms include:
* Red, sore eyes
* Photophobia, watery eyes, RCE
* Ocular surface discomfort
* Increasing blurred vision with age (vision impaired from childhood)
What are the early and later clinical signs of Reis-Buckler Dystrophy?
- Slowly progressive deterioration of vision
- Fine, patchy, sub-epithelial opacities in central cornea in early childhood
- Polycystic pattern extends out into the mid-periphery in 2nd to 3rd decades - increasing subepithelial haze becomes true scarring, irregular astigmatism, decreased corneal sensation
How is Reis-Buckler’s dystrophy managed?
- Manage RCEs
- Monitor for decreased vision
- Sx intervention usually required by the 5th decade
- Refer for superficial keratectomy or PTK to treat superfiical corneal scarring; lamellar or penetrating keratoplasty
Thiel-Behnke Corneal Thiel-Behnke Corneal Dystrophy is also knwon as ... dystrophy or ... dystrophy. It is very rare and similar to .... This has an ... inheritance. It has a significant symptomatic onset in ....
Px symptoms include:
* Red, ... eyes
* ..., watery eyes, ...
* Ocular surface discomfort
* Increasing ... with age but later than in ...dystrophy
Thiel-Behnke Corneal Dystrophy is also knwon as Honeycomb-shaped corneal dystrophy or Waardenburg-Jonkers dystrophy. It is very rare and similar to Reis-Buckler's. This has an autosomal dominant inheritance. It has a significant symptomatic onset in late childhood.
Px symptoms include:
* Red, sore eyes
* Photophobia, watery eyes, RCEs
* Ocular surface discomfort
* Increasing blurred vision with age but later than in Reis-Buckler'sdystrophy
What are the 3 clinical signs of Thiel-Behnke Corneal Dystrophy?
- Symmetrical, subepithelial, reticular (honeycomb) opacities, usually centrally
- Opacities can progress to depper stroma and peripherally overtime
- Vision will deteriorate with progression
Lattice dystrophy is the most common of ... dystrophies. It is caused by ... deposits at different levels within the .... This has an ... inheritance. Onset is ..., but usually ....
There are 4 variants, but Type ...(TGFB1 gene) is most common. This presents as ... within the stroma, starting ... and more .... This will later present as diffuse stromal ... with .... Px will have ..., decreased ... and reduced ... overtime.
Type ... is associated with systemic amyloidosis and have thicker lattice and begins ...
Type ... have lines going from ...
Lattice dystrophy is the most common of stromal dystrophies. It is caused by amyloid deposits at different levels within the stroma. This has an autosomal dominant inheritance. Onset is variable, but usually earlier rather than later.
There are 4 variants, but Type I(TGFB1 gene) is most common. This presents as fine, branching, refractile lines within the stroma, starting centrally and more superficially. This will later present as diffuse stromal ground glass haze with RCEs. Px will have photophobia, decreased corneal sensitivity and reduced VA overtime.
Type II is associated with systemic amyloidosis and have thicker lattice and begins peripherally
Type III & IV have lines going from limbus to limbus
What are the treatments of Lattice Dystrophy?
- Monitor closely and manage any surface discomfort & RCEs
- Referral if vision is significantly reduced for PTK; lamellar graft; penetrating keratoplasty
Granular dystrophy is also known as .... It is a very rare ... dystrophy. This is caused by ... at different levels within the .... This has an ... inheritance. Onset is usually ....
Clinical signs include:
* Initially central, ... anterior stromal ...
* Increasing ... and/or ...
* Eventually involves ...
* Areas between the opacities has ... appearance
Granular dystrophy is also known as Groenouw type I. It is a very rare stromal dystrophy. This is caused by hyaline deposits at different levels within the stroma. This has an autosomal dominant inheritance. Onset is usually childhood.
Clinical signs include:
* Initially central, crumb like anterior stromal opacities
* Increasing size and/or number
* Eventually involves deeper stroma
* Areas between the opacities has ground glass appearance
What are the treatments of granular dystrophy?
- Early: lubricants e.g. Hyloforte QID
- With time: Bandage CLs, PTK/ superficial keratectomy/ mild stromal or deep anterior lamellar keratoplasty/ penetrating keratoplasty
Avellino dystrophy is a variant of ... and ... dystrophies. This is characterised by .... in anterior ... and deeper .... It involves deposition of both ... and ... in corneal .... Many px can trace their ancestry back to ... in ..., where there is a .... Onset is usually in the ... and ... decades.
Clinical signs include: ... and ... stromal opacities among ...shaped opacities
Symptoms include: ..., RCEs and ...
Avellino dystrophy is a variant of granular and lattice dystrophies. This is characterised by granular deposits in anterior stroma and deeper lattice lines. It involves deposition of both amyloid and hyaline in corneal stroma. Many px can trace their ancestry back to Avellino in Itay, where there is a autosomal dominant. Onset is usually in the first and second decades.
Clinical signs include: icicles and star-shaped stromal opacities among disc-shaped opacities
Symptoms include: pain, RCEs and reduced vision
Macular dystrophy is the ... stromal dystrophy. It is the most severe form as it affects from .... This is caused by ... deposits. This has an ... inheritance. There are 2 subtypes:
* Type I: onset in ... and is more common, this type lacks ... in the cornea
* Type II: presents in ... with ... present in the cornea
Macular dystrophy is the least common stromal dystrophy. It is the most severe form as it affects from limbus to limbus. This is caused by glycosaminoglycan (GAG) deposits. This has an autosomal recessive inheritance. There are 2 subtypes:
* Type I: onset in childhood and is more common, this type lacks keratan sulphate in the cornea
* Type II: presents in 2nd decade with keratan sulphate present in the cornea
What are the 4 signs of macular dystrophy?
- Central, grey-white, ill-defined but realtively focal opacities with diffuse cloudiness in the intervening cornea
- Lesions extend from limbus to limbus and eventually can invovle the entire stromal thickness
- Corneal thickness and corneal sensitivity are often reduced
- Corneal endothelium often affected in late disease - guttae
What are the treatment of macular dystrophy?
- Refer for penetrating keratoplasty
Schnyder’s corneal dystrophy is also known as ... dystrophy. It is a rare, ... inheritance condition. It is caused by ... defect in ..., leading to ... in the .... This may be associated with systemic .... Onset of this is typically ... decade.
Clinical signs include ... in central ..., often associates with prominent ....
Px may experience increased ... and reduced ... in adulthood.
Schnyder’s corneal dystrophy is also known as crystalline stromal dystrophy. It is a rare, autosomal dominant inheritance condition. It is caused by metabolic defect in corneal keratocytes, leading to cholesterol (lipid crystal) deposition in the anterior stroma. This may be associated with systemic hypercholesterolaemia. Onset of this is typically 2nd or 3rd decade.
Clinical signs include white-yellow lipid deposits in central anterior stroma, often associates with prominent corneal arcus.
Px may experience increased glare and reduced vision in adulthood.
What are the treatments of Schnyder’s corneal dystrophy?
- Refer for blood workup of blood lipids as systemic disease may be life-threatening
- Refer for PTK to remove the superificial crystals causing severe glare
Fuch’s Endothelial Corneal Dystrophy is the most common ... dystrophy. This affects ... more than .... Cases ... inheritance are the most common, however this can also have ... or ... inheritance. Onset is usually in the ... decade and may be associated with COAG and AACG. This arises due to ... and ... of the .... Endothelial cells will become ... and .... There may be development of ... excrescences on the thickened ... appearing as ....
Fuch’s Endothelial Corneal Dystrophy is the most common endothelial dystrophy. This affects females more than males. Cases without inheritance are the most common, howeevr this can also have autosomal dominant or autosomal recessive inheritance. Onset is usually in the 5th decade and may be associated with COAG and AACG. This arises due to diffuse thickening and lamination of the Descemet's membrane. Endothelial cells will become sparse and atrophic. There may be development of hyaline excrescences on the thickened Descemet's membrane appearing as corneal guttae.
What are the progressive symptoms of Fuch’s Endothelial Corneal Dystrophy?
Early: asymptomatic
Moderate: Mild decrease in VA which increases over time as posterior stromal oedema increases
Late: epithelial oedema will develop resulting in a significant reduction in vision
* px may have worse vision upon waking and improves after several hours
* Guttata in endothelium
* epithelial bullae & microcysts - can rupture and cause pain
How is Fuch’s Endothelial Corneal Dystrophy treated and managed?
- 6/12 review
- Pachymetry, specular microscopy, IOP
- Corneal oedema - hypertonic saline 5%, warm haridryer over cornea upon waking to reduce epithellial oedema
- Bullae - ocular lubricants, bandage CL
- Refer for penetrating keratoplasty
Posterior Polymorphous Corneal Dystrophy is a rare ... dystrophy that affects ... and the .... It has an ... inheritance and onset in .... This is characterised by corneal endothelial cells having the appearance of ... along with ... and stain positive for .... This increases the risk of ... due to these cells growing into .... This may also be associated with ... which invovles ... and ....
Posterior Polymorphous Corneal Dystrophy is a rare endothelial dystrophy that affects Descemet's membrane and the endothelium. It has an autosomal dominant inheritance and onset in early childhood. This is characterised by corneal endothelial cells having the appearance of epithelial cells along with microvilli and stain positive for keratin. This increases the risk of glaucoma due to these cells growing into trabecular meshwork. This may also be associated with Alport's syndrome which invovles nephritis and sensori-neural hearing loss.
What are the 4 signs of Posterior Polymorphous Corneal Dystrophy?
- Grouped or linear bubble-like lesions at the level of Descemet’s membrane
- Lesions are frequently asymmetric
- Corneal oedema may develop in advanced cases
- Peripheral irido-corneal adhesions in about 25% of cases
What are the treatment and management of Posterior Polymorphous Corneal Dystrophy?
- Most do not require treatment for corneal changes
- Increased incidence of glaucoma in those with endothelial overgrowth, therefore must monitor IOP at each visit
