Granular Corneal Dystrophy, Type 1 (Classic) (GCD1)

Granular corneal dystrophy type 1 (GCD1), also known as Groenouw type I, is a bilateral hereditary corneal disorder characterized by the deposition of multiple, small, discrete, well-defined, grayish-white opacities in the anterior central stroma, sparing the limbus, during the first or second decade of life (Fig. 6.1) (Moller 1991; Weiss et al. 2015). The opacities of granular dystrophy may vary in shape and are classified into three basic morphologic types: drop-shaped, crumb-shaped, and ring-shaped (Weidle and Lisch 1984). The overall pattern of deposition is ray—or disk-shaped (Weidle and Lisch 1984). Initially, the stroma between the opacities remains clear. Although there is usually no associated discomfort or decrease in vision in the early stages of the disease, some patients may have mild photophobia from light scattering by corneal lesions. Glare, photophobia, and painful recurrent erosions often occur in advanced stages of the disease.