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
