CORNEAL DYSTROPHIES

CORNEAL DYSTROPHIES

Group of disorders, characterised by a non-inflammatory, inherited, bilateral opacity of the cornea.
There is no vascularisation of cornea.
Dystrophies are classified according to anatomical involvement.

Anterior corneal Dystrophies

Stromal corneal Dystrophies

Posterior Corneal Dystrophies

Epithelium:

Meesamnn’s dystrophy
Epithelium Basement membrane dystrophy

Bowmnann’s layer:

Reis- Bucklers dystrophy
Anterior membrane dystrophy of Grayson-Wilbrandt
Honycomb dystrophy of Thiel & Behnke
Subepithelial mucinous corneal dystrophy

Stroma:

Granular dystrophy (Groenouw’s type 1)
Lattice dystrophy (Type I, Type III, IIIA & IV)
Macular dystrophy
Gelatinous droplike dystrophy
Fleck dystrophy
Pre- Descement dystrophy
Avellino’s dystrophy
Meretoja syndrome (Lattice type II)
Marginal crystalline dystrophy of Bietti

Endothelial dystrophy:

Fuch’s endothelial dystrophy
Congenital hereditary endothelial dystrophy
Posterior polymorphous dystrophy

Epithelial basement membrane dystrophy is the most common Anterior Corneal Dystrophy

Lattice dystrophy is the most common Stromal Corneal dystrophy.
Lattice Type I is the commonest type of dystrophy.
Endothelial corneal Dystrophy is the least common of the classical stromal dystrophies

Fuch’s Endothelial Dystrophy is the most common Posterior/Lattice Dystrophy

Fuch’s epithelial-endothelial dystrophy

Fuch’s dystrophy-slowly progressive bilateral condition.
Affecting females more than males.
Primary open angle glaucoma is associated with this cobdition.

Stages & Clinical features

1. Stage of cornea guttata

Hassal-Henle type of excrescences in the central part of cornea.
A gradual increase of central guttae with peripheral spread & confluence gives rise to the so called ‘beaten-metal appearance’.
This stage is asymptomatic.

2.Oedematous stage or Stage of endothelial decompensation

Early stromal edema & epithelial dystrophy
Patients complain of blurring of vision.

3. Stage of Bullous keratopathy

Follows long standing stromal edema.
Marked epithelial edema with formation of bullae,

4. Stage of scarring

Cornea becomes opaque & vascularised.
May be complicated by secondary infection or glaucoma.

Treatment

1. Edematous stage: 5% Sodium chloride (Hypertonic saline).

2. Bullous keratopathy: Bandage soft contact lenses.

3. Penetrating keratoplasty: treatment of choice

Exam Important

Corneal dystrophies are degenerations that are usually Primary and bilateral.