Background
Lattice dystrophy is usually an autosomal dominant condition and is the most common of stromal dystrophies. Like granular and Avellino dystrophy, the genetic defect of lattice dystrophy has been mapped to the BIGH3 gene on chromosome 5q.[1] Onset of the corneal changes usually occurs in the first decade of life, although patients may remain asymptomatic for years. Examination of the cornea in the second to third decade of life reveals branching, refractile lattice lines with intervening haze, which are observed best in retroillumination. An example of lattice corneal dystrophy is shown in the image below.
Lattice corneal dystrophy. Image courtesy of James J. Reidy, MD, FACS, Associate Professor of Ophthalmology, State University of New York, School of Medicine & Biomedical Sciences, Buffalo, New York. Pathophysiology
The cornea is the clear outer coat of the front of the eye. A dystrophy of the cornea is defined as a bilateral noninflammatory clouding of the cornea. The corneal dystrophies can be placed into 3 categories based on their location within the cornea as follows: (1) the anterior corneal dystrophies affect the corneal epithelium and may involve the Bowman membrane, (2) stromal corneal dystrophies affect the central layer of the cornea (the stroma), and (3) the posterior corneal dystrophies involve the Descemet membrane and the endothelium.
Most corneal dystrophies have onset when younger than 20 years (exceptions include map-dot-fingerprint dystrophy and Fuchs corneal dystrophy). Most corneal dystrophies are dominantly inherited, exceptions are macular dystrophy, type 3 lattice dystrophy, and the autosomal-recessive form of congenital hereditary endothelial dystrophy.
Epidemiology
Frequency
United States
Although lattice dystrophy is the most common of the stromal dystrophies, it is relatively rare.
Mortality/Morbidity
Excessive corneal erosions can lead to decreased visual acuity, which may require a corneal transplant or phototherapeutic keratectomy (PTK).
Sex
No sexual predilection is noted.
Age
Onset of the corneal changes usually occurs in the first decade of life, although patients may remain asymptomatic for years. Examination of the cornea in the second to third decade of life reveals branching, refractile lattice lines, which are observed best in retroillumination. Over time, the lattice lines and other opacities coalesce, forming anterior stromal haze that decreases the visual acuity.
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