Dystopia canthorum is a medical term for the lateral displacement of the inner corners of the eyes, known as the medial canthi. This displacement creates the appearance that the eyes are spaced more widely apart. However, this is a specific anatomical finding based on precise measurements, not just a subjective observation. The condition is a physical trait rather than a disease, and its presence can indicate how certain craniofacial structures developed.
Identifying Dystopia Canthorum
The primary characteristic of dystopia canthorum is an increased inner canthal distance (ICD). In this condition, the distance between the pupils of the eyes, or the interpupillary distance (IPD), remains normal. This distinction is fundamental to identifying the condition correctly.
It is important to differentiate dystopia canthorum from telecanthus and hypertelorism. Telecanthus is a broader term for an increased inner canthal distance, and dystopia canthorum is a specific type of it. Hypertelorism involves an increased distance between the entire eye sockets, meaning both the inner canthal and interpupillary distances are wider than normal.
With dystopia canthorum, only the soft tissues of the inner eyelids are displaced, while the bony structures of the skull remain in a normal position. The visual effect is a seemingly broad nasal bridge, with more of the white of the eye (the sclera) visible toward the nose.
Underlying Causes and Associated Syndromes
Dystopia canthorum is a congenital physical trait pointing to an interruption in early craniofacial development. It is frequently associated with genetic syndromes, and its presence often prompts investigation for an underlying condition.
The most prominent genetic disorder linked to dystopia canthorum is Waardenburg syndrome (WS). In Waardenburg syndrome type 1, it is a defining feature, present in approximately 99% of affected individuals. This syndrome also involves changes in pigmentation, such as a white forelock, eyes of different colors, and hearing loss. Waardenburg syndrome type 3 presents with similar facial features but also includes abnormalities of the upper limbs.
Another condition is Blepharophimosis, Ptosis, Epicanthus Inversus Syndrome (BPES). This disorder is characterized by narrowed eye openings (blepharophimosis), droopy eyelids (ptosis), and an upward fold of the lower eyelid skin (epicanthus inversus). While its features can be mistaken for Waardenburg syndrome, BPES is not associated with the hearing loss or pigmentation changes.
Diagnosis and Medical Evaluation
A formal diagnosis is made by a specialist, such as a craniofacial surgeon or a clinical geneticist. This process involves taking highly specific measurements of the facial features to objectively quantify the distances between different points of the eyes.
Clinicians measure the inner canthal distance (ICD), the interpupillary distance (IPD), and the outer canthal distance. To confirm dystopia canthorum, these measurements are used to calculate a value known as the “W-index.” This biometric formula provides a standardized score, and a value greater than 1.95 confirms the diagnosis.
Treatment and Management
Since dystopia canthorum does not interfere with vision, treatment is not always medically required. The decision to pursue intervention is often based on cosmetic considerations and the psychological impact the condition may have on an individual. When treatment is sought, it is surgical.
The primary surgical procedure is a medial canthopexy. This operation involves repositioning the medial canthal tendons, which anchor the inner corners of the eyelids to the bone. Moving these tendons closer to the midline of the face reduces the distance between the inner canthi.
The timing of such a procedure is a consideration, and it is often postponed until a child’s facial bones have reached a certain stage of development. This delay helps ensure the surgical correction is stable and proportional to the patient’s mature facial structure.