STROMAL CORNEAL DYSTROPHIES

Granular dystrophy
Also known as 'Groenouw type I, is an autosomal
dominant dystrophy characterised by milky-granular
hyaline deposits in anterior stroma. Intervening
stroma is clear. The condition developing in first
decade of life is slowly progressive and usually
asymptomatic. Occasionally visual acuity may be
severely impaired, requiring keratoplasty.

Macular dystrophy (Groenouw type-II)
It is an autosomal recessive dystrophy characterised
by appearance of dense grey opacity in the central
cornea. The condition results due to accumulation of
mucopolysaccharides owing to a local enzyme
deficiency. It occurs in childhood (5 to 10 years) and
leads to marked defective vision in early life, which
usually requires penetrating keratoplasty.

Lattice dystrophy
Also known as 'Biber-Haab-Dimmer dystrophy. It is
an autosomal dominant disease characterised by
branching spider-like amyloid deposits forming an
irregular lattice work in the corneal stroma, sparing the
periphery. It appears at the age of 2 years, but the
occurrence of recurrent erosions and progressive
clouding of central cornea is apparent by the age of 20
years. Soon, visual acuity is impaired. Usually
penetrating keratoplasty is required by the age of 30-
40 years.

Schnyder's crystalline dystrophy
It is an autosomal dominant dystrophy characterised
by a round ring-shaped central corneal stromal opacity
due to deposition of fine needle-like cholesterol
crystals, which may be white to yellow or
polychromatic in colour. The dystrophy appears in
early infancy or at birth or sometimes in the first
decade of life. It is slowly progressive and usually
asymptomatic.