Corneal Dystrophy

Excerpt

Corneal dystrophy (CD) is most recently defined as a collection of rare hereditary non-inflammatory disorders of abnormal deposition of substances in the cornea. CD was coined in 1890 by Arthur Groenouw and Hugo Biber, and the efforts of Ernst Fuchs, Wilhelm Uhthoff, and Yoshiharu Yoshida solidified the foundation of the understanding of these diseases. As proposed in 2015 by the International Classification of Corneal Dystrophies (IC3D), CD is sub-classified by the anatomic location affected: epithelial/subepithelial, epithelial-stromal, stromal, and endothelial dystrophies. Discoveries and unique case studies continue to broaden our understanding and classification of these diseases; therefore, it is difficult to categorize every single dystrophy solely into these four major labels.

The objective of this article is to present an overview of the evaluation and management for the most prominent and understood variants of CD. Highlights of these dystrophies will be discussed. However, further in-depth discussion on these dystrophies will be in separate StatPearls articles.

Patients with CD can be asymptomatic, but if symptoms occur, they typically experience bilateral visual acuity loss, typically in the form of irregular astigmatism. Depending on the corneal layer affected, patients may also manifest with photophobia, dry eyes, corneal edema, and recurrent corneal erosions, especially with epithelial-based CD, which causes considerable pain. Symptoms can begin at any age, depending on the diagnosis. Treatment can range from conservative measures to corneal transplantation.

CD is a significant but rare ocular disease. The genetic component of this disease is important for patients to understand, especially for affected patients involved with family planning. As we begin to understand genetics in greater detail, better evaluation and treatments for CD will come to fruition.

The objective of this article is to present an overview of the general evaluation and management for the most prominent and understood variants of CD. Highlights of these dystrophies will be covered, but the author intends to elaborate on these dystrophies separately in other StatPearls articles. The variants of CD based on their new anatomic classifications in IC3D are:

Epithelial and subepithelial dystrophies

1. Epithelial basement membrane corneal dystrophy (EBMCD), also previously known as map-finger-dot dystrophy, Cogan microcystic dystrophy, and anterior basement membrane dystrophy.

2. Epithelial recurrent erosion dystrophies (EREDs) which includes Franceschetti corneal dystrophy, dystrophia smolandiensis, and dystrophia helsinglandica

3. Subepithelial mucinous corneal dystrophy (SMCD)

4. Meesmann corneal dystrophy (MECD) also known as juvenile epithelial corneal dystrophy

5. Lisch epithelial corneal dystrophy (LECD)

6. Gelatinous drop-like corneal dystrophy (GDLD)

Epithelial-Stromal Dystrophies (still included under epithelial and subepithelial dystrophies)

1. Lattice corneal dystrophy (LCD), with its subtypes: type I (TGFBI mutation) and type II (familial amyloidosis Finnish type), including LCD variants

2. Granular corneal dystrophy (GCD), types I and II (Avellino-type)

3. Reis-Bückler’s corneal dystrophy (RBCD)

4. Thiel-Behnke corneal dystrophy (honeycomb dystrophy) (TBCD)

Stromal dystrophies

1. Macular corneal dystrophy (MCD)

2. Schnyder corneal dystrophy (SCD)

3. Congenital stromal corneal dystrophy (CSCD)

4. Fleck corneal dystrophy (FCD)

5. Posterior amorphous corneal dystrophy (PACD)

6. Pre-Descemet corneal dystrophy (PDCD)

7. Central cloudy dystrophy of francois (CCDF)

Endothelial Corneal Dystrophies

1. Fuchs endothelial corneal dystrophy (FECD)

2. Posterior polymorphous corneal dystrophy (PPCD)

3. Congenital hereditary endothelial dystrophy (CHED)

4. X-linked endothelial corneal dystrophy (XECD)