Phenomenology of eccentric fixation.

The purpose of this paper is to discuss the pathology and clinical features of limbal der­ moids and to illustrate these features with case records from the Wills Eye Hospital. A dermoid may be defined as a solid con­ genital tumor consisting of mesoblastic tis­ sue (fibrous and fatty usually) covered by ectoderm (skin) and invaded by ectodermal derivatives, that is, hair follicles, sebaceous and sweat glands. The term lipodermoid is used synonymously with dermoid. Dermoid tumors should not be confused with dermoid cysts which are formed by the invagination of epithelium along embryonic fissures. Der­ moid cysts do not occur on the globe. One should also distinguish between dermoids and dermolipomas, the latter occurring subconjunctivally and consisting primarily of fat. Rarely a dermoid and dermolipoma may occur in the same patient. Teratomas con­ taining cartilage and bone may occur at the limbal area in the same location as der­ moids.