A large cohort comprising four kindreds of patients with Schnyder's dystrophy has been identified in central Massachusetts. All patients were Swede-Finn with ancestry from the southwest Finnish coast on the Bay of Bothnia.Of 60 members of this cohort examined by one of the authors (JSW), 18 had evidence of Schnyder's dystrophy. One female with Schnyder's dystrophy from each of three kindreds underwent penetrating keratoplasty for decreased visual acuity. We examined 4 corneal buttons from these unrelated women, aged 47, 63, and 72 years.The fluorescent probe filipin revealed that the majority of the lipid deposits were rich in unesterified cholesterol. Electron microscopy demonstrated abnormal accumulation of lipid and dissolved cholesterol in the epithelium, Bowman's layer, and throughout the stroma. Examination of the kindreds reflected the variable expression of crystals, which were present only in two patients, the 47-year-old and 63-year-old women.Ultrastructural and histochemical studies showed the panstromal localization of lipid in Schnyder's corneal dystrophy in three patients with Schnyder's dystrophy who underwent penetrating keratoplasty.