Corneal dystrophy Granular corneal dystrophy SNOMEDCT_US:45283008 HP:0007802 UMLS:C0018179 The presence of central, fine, whitish granular lesions in the stroma of the cornea. This type of corneal dystrophy is usually asymptomatic and begins in childhood and shows a slow progression. Later in the course, the corneal epithelium and Bowman's layer may be affected. Histologically, the cornea shows a uniform deposition of hyaline material.