It is not unusual for benign growths of tissue to appear in certain structures including the eye. When it is tissue not normally found in that location it is called a choristoma. In the condition described here, sometimes called ring dermoid of the cornea, it is skin-like tissue that grows at the edge of the cornea (the windshield of the eye).
Small yellow-white bumps of tissue are present at birth and may extend around the entire circumference of the cornea in one or both eyes. In other cases the dermoid tissue appears as a dark ring. The tissue is often elevated two to three millimeters and extends onto both the cornea and the conjunctiva (outer covering of the globe) for 3-5 mm. In some patients this results in considerable distortion of the cornea resulting in astigmatism and in others vision becomes impaired later in life. Patients sometimes have glaucoma and congenital cataracts.
This disorder is confined to the eye.
This is an autosomal dominant disorder in which both sexes are equally affected. The condition is passed to children by an affected parent.
The diagnosis is made by an ophthalmologist. It can be surgically removed but this is not always necessary. The astigmatism may be correctable with refractive surgery. The condition requires monitoring for growth and the development of glaucoma. Congenital cataracts can be surgically removed.