| A rare developmental defect during embryogenesis with a typically unilateral, partial or full-thickness, variably sized defect of the superior eyelid, ranging from a small notch to complete absence of the entire lid, which is commonly triangular in shape (with base at eyelid margin) and located on the medial third of the lid. It can occur isolated, associated with other anomalies (e.g. ocular/orbital and facial), or as part of a syndrome. |