This article was written by Assoc. Prof. Dr. Burak Sercan Erçin and is based on clinical experience. A specialist in Plastic, Reconstructive and Aesthetic Surgery; prepared in accordance with current medical literature and personal surgical data. A consultation is recommended before making any medical decisions.
Hypertelorism is not, strictly speaking, a disease. It is a physical finding — an increased distance between the bony orbits that contain the eyes — that can occur in isolation or as one feature of a broader craniofacial condition. The classification most craniofacial surgeons rely on is the Tessier grading system, which sorts hypertelorism into three grades based on the measured interorbital distance and forms the starting point for every clinical decision that follows. This guide, written from the perspective of Assoc. Prof. Dr. Burak Sercan Erçin, an EBOPRAS-certified plastic and reconstructive surgeon in Istanbul with a subspecialty background in craniofacial surgery, covers what hypertelorism is, what causes it, how surgeons grade it, when surgery is indicated, what the reconstructive techniques actually involve, and how the family journey works for international patients travelling to Turkey.
Unlike much of the online material on this subject, this article is written for two audiences at once: parents of children with a diagnosed or suspected craniofacial condition involving hypertelorism, and adult patients with milder isolated hypertelorism who are considering assessment for the first time. Both audiences deserve accurate, unhurried, clinical-grade information, and both are addressed in the sections below.
What Hypertelorism Actually Is
Hypertelorism describes an abnormal increase in the distance between the bony eye sockets, known clinically as the orbits. Because the position of the orbits is fixed by the surrounding skull bones, the underlying issue is one of bone development rather than soft tissue. The eyes themselves are usually structurally normal and function normally; what has changed is the frame in which they sit. Three anatomical distances are measured to establish a diagnosis:
- Inner canthal distance (ICD): the distance between the inner corners of the eyes.
- Outer canthal distance (OCD): the distance between the outer corners of the eyes.
- Interpupillary distance (IPD): the distance between the centres of the two pupils.
A value above the 95th percentile for age and sex on all three measurements confirms true orbital hypertelorism, as distinct from pseudohypertelorism (a wider-appearing eye spacing caused by soft-tissue features rather than actual bone separation). Making this distinction correctly is important because pseudohypertelorism does not require the same reconstructive approach and often does not require surgery at all.
The Tessier Grading System: How Surgeons Actually Classify Hypertelorism
The internationally accepted grading system for adult hypertelorism was developed by Paul Tessier, one of the founding figures of modern craniofacial surgery. Tessier’s system uses the interorbital distance measurement to stratify severity and, in turn, to guide the surgical decision. The three grades are as follows:
| Grade | Interorbital distance | Clinical picture |
| Grade I | 30 to 34 mm | Mild hypertelorism. Cosmetic concern primarily, often does not require surgical correction. Non-surgical management and monitoring frequently appropriate. |
| Grade II | 35 to 39 mm | Moderate hypertelorism. Surgical correction should be considered based on functional impact, associated conditions, and psychosocial factors. |
| Grade III | Greater than 40 mm | Severe hypertelorism with gross facial disfigurement. Surgical intervention is generally indicated. Typically corrected via box osteotomy or facial bipartition. |
In children, whose facial dimensions are still developing, hypertelorism is graded not by fixed millimetre thresholds but by standard deviations from age- and sex-matched normal data. Paediatric assessment is therefore always relative to developmental norms rather than absolute values. This is why an accurate diagnosis in a child requires a specialist who works regularly with paediatric craniofacial reference data, not a general assessment.
The Five Underlying Causes: Why Correct Diagnosis Comes Before Any Treatment Decision
A published set of five diagnostic criteria organises the underlying causes of hypertelorism into distinct categories. This classification matters clinically because the underlying cause directly determines both the surgical approach and the expected long-term outcome. The five categories are:
1. Frontonasal malformations
Developmental anomalies of the front of the face and nose. These often involve a broadened nasal root, a widened bridge, and variable degrees of clefting of the midline soft tissue. Frontonasal dysplasia is the most commonly cited example within this group.
2. Craniofrontonasal dysplasia (CFND)
An X-linked genetic condition first described by Cohen in 1979, characterised by hypertelorism, brachycephaly (shortened front-to-back skull shape), craniosynostosis (premature fusion of skull sutures), and various joint findings. CFND paradoxically affects females more severely than males, an inheritance pattern that continues to inform genetic counselling in affected families.
3. Craniofacial clefts
Rare congenital clefts affecting the bones and soft tissues of the face, classified using Tessier’s own numeric system (Tessier clefts 0 through 14). Craniofacial clefts involving the midline (Tessier 0 to 14) or the paramedian region (Tessier 1 to 12) commonly produce orbital hypertelorism as a secondary feature.
4. Encephaloceles
Congenital defects in which brain tissue and its coverings protrude through a defect in the skull. Frontoethmoidal encephaloceles, which protrude through the front of the skull between the eyes, mechanically push the developing orbits apart and produce hypertelorism as a direct anatomical consequence. Reconstruction in these cases must address the encephalocele itself alongside the orbital repositioning.
5. Syndromic and chromosomal disorders
Hypertelorism is a recognised feature of numerous genetic syndromes, most notably Apert syndrome and Crouzon syndrome (both craniosynostosis syndromes), Aarskog syndrome, and a range of less common chromosomal disorders. In these patients, hypertelorism is one clinical finding among several, and the overall management plan must consider the whole syndrome rather than the orbital position alone.
When Surgery Is Indicated, and When It Is Not
Not every patient with hypertelorism requires or benefits from surgery. The decision to proceed with correction is a considered one, based on the balance of five factors that should be discussed openly at consultation:
- Tessier grade: Grade I hypertelorism (30 to 34 mm) is typically managed non-surgically unless there is a specific psychosocial or functional reason to intervene. Grade II (35 to 39 mm) is a considered decision. Grade III (over 40 mm) is a surgical indication in most cases.
- Underlying cause: A patient with hypertelorism caused by an active mass or encephalocele has a different urgency and a different treatment sequence from a patient with stable isolated hypertelorism from a developmental origin.
- Functional impact: Effects on vision, binocular fusion, strabismus, or airway function all shift the calculus toward earlier surgery.
- Psychosocial factors: Facial visibility of the condition, particularly in a school-age child, is a legitimate reason to consider correction, and published research documents significantly reduced psychological burden in families whose children were treated at an appropriate developmental stage.
- Feasibility and safety: The surgical complexity, availability of the multidisciplinary team, and the child’s or patient’s overall health status all factor into the decision timing.
For many patients with Grade I hypertelorism, and for some patients with stable Grade II, the appropriate path is monitoring with regular clinical assessment rather than immediate surgery. This is a valid clinical option and one that a responsible craniofacial surgeon will actively recommend when it fits the patient’s situation.
The Two Principal Surgical Techniques: Box Osteotomy and Facial Bipartition
Surgical correction of hypertelorism is performed through one of two principal approaches, each with defined indications, technique, and outcomes. Both are major craniofacial operations performed jointly by plastic surgery and neurosurgery teams under general anaesthesia, and both should only be undertaken at centres with the multidisciplinary expertise and hospital infrastructure required.
Orbital box osteotomy
The box osteotomy technique, refined by Tessier in the 1960s and 1970s, involves the surgical mobilisation of each entire bony orbit as a complete anatomical box. The orbits are cut free from the surrounding skull with a series of precisely planned osteotomies, moved medially (toward the midline) to a new corrected position, and secured with plates and screws. The excess bone between the orbits is removed, and the resulting facial deformity is reconstructed with bone grafts (typically harvested from the cranial vault or ribs) to fill the newly-shaped nasal and forehead regions. Box osteotomy is generally preferred when the orbital position is the primary issue and the upper face and dental occlusion are relatively normal.
This is the technique the site’s existing orbital box osteotomy page covers in more depth, and it is one of the most technically demanding operations in craniofacial surgery. Modern practice uses computer-assisted surgical planning and three-dimensional printed cutting guides to improve precision and shorten operating time.
Facial bipartition
Facial bipartition is a more extensive procedure in which the entire mid-face is split vertically down the midline into two halves, which are then rotated inward and secured in the corrected position. This approach is preferred when hypertelorism is accompanied by a widened nasal bridge, an inverted-V midface, or dental malocclusion, because the bipartition simultaneously corrects the orbital position, the nasal width, and the arch of the upper dental line in a single operation. It is more complex than box osteotomy and is typically reserved for cases where the full midface reconstruction is anatomically necessary.
Ancillary procedures
Depending on the specific case, the primary hypertelorism correction is often combined with one or more of the following in the same surgical episode or in staged sequential procedures: cranial vault reshaping (in patients with craniosynostosis), rhinoplasty to reconstruct the nasal bridge, medial canthal ligament repositioning to restore the natural inner-eye contour, and, where indicated, orbital roof or floor reconstruction. Every plan is individualised to the specific anatomy identified on three-dimensional imaging.
| 🩺 Dr. Burak’s Clinical Note “The choice between box osteotomy and facial bipartition is not a preference. It is dictated by the specific anatomy of the patient. When I look at three-dimensional CT imaging with a family for the first time, one of the two techniques is usually clearly indicated by the underlying midface pattern. What matters most is not which technique is used but that the technique matches the anatomy, and that the multidisciplinary team performing the surgery has the volume and experience to execute it well. This is not an operation to have performed by a surgeon or a centre that does one or two of these cases a year.” |
Timing of Surgery: Traditional Preschool Age, Late Correction, and Adult Patients
The traditional teaching in craniofacial surgery is that hypertelorism correction should be performed before the age of 8 years. The rationale is threefold: the mid-face has completed most of its early growth by this age; the child has not yet entered the school years in which appearance-related peer interactions become socially significant; and post-operative healing and bone consolidation in a growing child produce more natural long-term results. For paediatric patients with Grade II or Grade III hypertelorism, planning surgery to fall between the ages of 4 and 8 remains the standard approach when family circumstances and clinical status support it.
This does not mean surgery is inappropriate at other ages. Late correction of hypertelorism in adolescents and adults is well documented in the peer-reviewed literature, with published case series describing successful box osteotomy in adult patients. Adult correction typically involves the same core techniques with several important modifications: the bones are more brittle and require more careful osteotomy planning, dental occlusion considerations become more prominent, and the psychosocial context of an adult patient making the decision independently is fundamentally different from that of a family deciding on behalf of a young child.
Adult isolated hypertelorism is a specific presentation that deserves separate discussion. Some adults present in their 20s, 30s, or later with mild-to-moderate hypertelorism they have lived with throughout life, often as an isolated feature without a broader syndrome. These patients have full personal insight into how the finding has affected them, and their decisions about whether to proceed with surgery are often more clearly considered than the decisions parents make on behalf of pre-verbal children. Adult surgery is entirely feasible for appropriate candidates and produces high satisfaction when carefully selected.
The Family and Patient Journey When You Come to Istanbul
Istanbul has developed into one of the leading global destinations for reconstructive craniofacial surgery, with JCI-accredited hospitals, deep concentration of subspecialist expertise, and total costs typically 50 to 70 percent lower than the equivalent care in the UK, US, or Australia. For families considering treatment for a complex craniofacial condition, this cost differential can make specialist surgery accessible that would otherwise be out of reach. The typical journey looks like this:
- Initial remote consultation: photographs, existing imaging, and history reviewed via WhatsApp or video call. No obligation to travel.
- Ongoing remote follow-up: many families and adult patients are followed remotely for months or years while their situation is monitored or evaluated.
- In-person consultation and multidisciplinary planning: on arrival in Istanbul, formal clinical assessment, three-dimensional CT imaging if not already available, discussion with the joint plastic surgery and neurosurgery team, and confirmation of the surgical plan.
- Surgery day: procedure performed at a JCI-accredited hospital under paediatric or adult craniofacial anaesthesia protocols as appropriate.
- Immediate post-operative period: hospital observation for the initial recovery period, typically several days depending on the specific procedure.
- Discharge to hotel-based recovery: transition to accommodation with continued WhatsApp support from the medical team.
- Clearance for return travel: typically 10 to 14 days after major craniofacial surgery, depending on healing and the specific procedure performed.
- Remote follow-up after return home: photograph review at defined intervals, and a second brief trip arranged for any planned staged procedures or scar review.
The credential to look for in Turkey remains EBOPRAS certification, held by Assoc. Prof. Dr. Burak Sercan Erçin alongside his Turkish Board certification and academic faculty position at Bahçeşehir University. His subspecialty background in reconstructive and craniofacial surgery, including training with Dr. Pedro Cavadas, is directly applicable to hypertelorism correction. Related site content covers complex facial reconstruction, facial reconstructive surgery, the orbital box osteotomy technique, and the trauma face reconstruction pathway.
Recovery and Long-Term Outcomes
Recovery from hypertelorism correction is more substantial than for most aesthetic operations and reflects the complexity of the underlying reconstruction. The immediate post-operative period involves several days of hospital care for close monitoring of neurological function, orbital position, and wound healing. Facial swelling reaches its peak in the first week and gradually resolves over four to six weeks. The orbital position begins to appear settled at approximately three months, with final aesthetic results emerging over 6 to 12 months as swelling fully resolves and bone consolidation completes.
Long-term outcomes are generally favourable when surgery is performed at an experienced centre. Published case series report high rates of satisfactory functional and aesthetic results, with the most common issues in follow-up being minor asymmetries requiring small revision procedures and, occasionally, medial canthal ligament repositioning refinements. In paediatric patients, the growing skull can produce some late relapse of orbital position over years, which is why long-term monitoring through the growth years is standard practice.
Post-operative scar management follows the same principles as other facial reconstructive procedures: silicone-based scar therapy, sun protection, and, where indicated, adjunctive treatments such as exosome therapy to support optimal healing. Dr. Burak’s team provides WhatsApp-based photograph review through the first year to guide scar management remotely for international patients.
Frequently Asked Questions
What is hypertelorism?
Hypertelorism is an abnormal increase in the distance between the bony orbits (eye sockets), typically defined as measurements above the 95th percentile for age and sex on inner canthal, outer canthal, and interpupillary distances. It is a physical finding rather than a disease in itself and can occur in isolation or as part of a broader craniofacial or syndromic condition. Accurate diagnosis requires identification of both the measurement and the underlying cause.
What causes hypertelorism?
Hypertelorism has five main causes according to published diagnostic criteria: frontonasal malformations, craniofrontonasal dysplasia, craniofacial clefts (Tessier clefts), encephaloceles, and syndromic or chromosomal disorders including Apert and Crouzon syndromes. Each cause has a distinct clinical picture and directly influences the appropriate treatment approach. Identifying the specific underlying cause through genetic testing and three-dimensional imaging is essential before any surgical decision is made.
What is the Tessier grading system for hypertelorism?
The Tessier grading system classifies adult orbital hypertelorism into three grades based on interorbital distance: Grade I (30 to 34 mm) is mild and often does not require surgery; Grade II (35 to 39 mm) is a considered decision based on multiple factors; Grade III (over 40 mm) is severe and generally indicates surgical correction. In children, grading is based on standard deviations from age- and sex-matched normal data rather than absolute measurements.
When should hypertelorism surgery be performed?
The traditional recommendation is correction before the age of 8, when the mid-face has completed most of its early growth but the child has not yet reached the school-age period in which facial appearance becomes socially prominent. However, late correction in adolescents and adults is well established in the literature and produces good outcomes for appropriately selected patients. Adult patients with isolated mild-to-moderate hypertelorism may proceed at any age based on their individual situation.
What are the two main surgical techniques for hypertelorism?
The two principal techniques are box osteotomy, in which each bony orbit is mobilised as a complete anatomical unit and repositioned medially, and facial bipartition, in which the entire mid-face is split vertically and rotated inward. Box osteotomy is preferred when the orbital position is the primary issue and the upper face and dental occlusion are relatively normal. Facial bipartition is preferred when hypertelorism is accompanied by mid-face widening, nasal bridge broadening, or dental malocclusion that a bipartition can address simultaneously.
Can adult patients with hypertelorism have surgery?
Yes. Late surgical correction of hypertelorism in adolescent and adult patients is documented in the peer-reviewed craniofacial literature. Adult surgery involves the same core techniques with modifications for bone density, dental occlusion, and the different psychosocial context of an adult making the decision independently. Adult patients with isolated mild-to-moderate hypertelorism, in particular, are often excellent candidates when appropriately assessed.
Does Dr. Burak treat international patients for hypertelorism?
Yes. Dr. Burak’s practice includes paediatric and adult reconstructive craniofacial cases for international families. Initial photographic and imaging assessment is conducted online via WhatsApp or video call before any decision to travel. Many families are followed remotely for extended periods while monitoring the condition, before any surgery is considered. Visit the contact page or reach out via WhatsApp.
An Individualised Diagnosis, an Individualised Plan
Hypertelorism is not a single condition with a single answer. It is a physical finding that appears in a range of underlying craniofacial situations, from stable isolated presentations that require no more than periodic monitoring to complex syndromic cases that call for coordinated multidisciplinary reconstruction across years of care. What every patient shares is the need for accurate diagnosis, honest discussion of what surgery can and cannot achieve, and access to a craniofacial team with the volume and expertise to perform the specific operation their anatomy requires.
For families and adult patients considering assessment or treatment in Istanbul, the value of a consultation with an EBOPRAS-certified craniofacial surgeon is not the promise of a specific surgical outcome. It is the possibility of a careful, unhurried conversation that begins with photographs and imaging shared over WhatsApp and continues, in many cases, for months before any operation is planned. That conversation is where the right decision for your family or your case is made.
Why Assoc. Prof. Dr. Burak Sercan Erçin
Dr. Burak Sercan Erçin is an Istanbul-based Plastic, Reconstructive and Aesthetic surgeon with more than 15 years of experience and over 6,000 operations. He holds both Turkish Board and EBOPRAS certifications, trained alongside reconstructive microsurgeon Dr. Pedro Cavadas, and serves as academic faculty at Bahçeşehir University. He practices at Pendik Medical Park, Istanbul. His subspecialty background in reconstructive and craniofacial surgery is directly applicable to hypertelorism correction, where the ability to match the surgical technique to the specific underlying cause defines the long-term outcome. To discuss your case, book an online consultation or reach out via WhatsApp.
This content was written by Assoc. Prof. Dr. Burak Sercan Erçin in line with clinical experience and current medical literature. It is intended for general informational purposes only and does not constitute medical advice. A personal consultation with Dr. Erçin is recommended for individual assessment.
Faculty Member · Bahçeşehir University
Graduate of Ege University Faculty of Medicine, Assoc. Prof. Dr. Erçin completed advanced fellowships at Tampa General Hospital (USA) under Dr. Deniz Dayıcıoğlu in breast reconstruction and burn surgery, and at the clinic of Dr. Pedro Cavadas in Valencia, Spain in reconstructive microsurgery. After passing the EBOPRAS examination in 2018, he joined Bahçeşehir University as a faculty member and continues his private practice on Bağdat Avenue, Istanbul, specialising in face, breast and body aesthetics alongside complex reconstructive surgery.
