BPES is very rare: only 50-100 cases have been described. It affects slightly more males than females.

Though BPES can be suggested by the presence of blepharophimosis, ptosis, and/or epicanthus inversus, it can only be definitively diagnosed by genetic testing. Other disorders that appear similar include Waardenburg syndrome and Ohdo blepharophimosis syndrome.

The most common causes in young children are birth trauma and a type of cancer called neuroblastoma. The cause of about a third of cases in children is unknown.

Blepharophimosis is a congenital condition characterized by a horizontally narrow palpebral fissure. It is also part of a syndrome blepharophimosis, ptosis, and epicanthus inversus syndrome, also called blepharophimosis syndrome, which is a condition where the patient has bilateral ptosis with reduced lid size, vertically and horizontally. The nasal bridge is flat and there is hypoplastic orbital rim. Both the vertical and horizontal palpebral fissures (eyelid opening) are shortened; the eyes are also spaced more widely apart than usual, also known as telecanthus.

Vignes (1889) probably first described this entity, a dysplasia of the eyelids.

As with almost every kind of surgery, the main complications in both treatments of hypertelorism include excessive bleeding, risk of infection and CSF leaks and dural fistulas. Infections and leaks can be prevented by giving perioperative antibiotics and identifying and closing of any dural tears. The risk of significant bleeding can be prevented by meticulous technique and blood loss is compensated by transfusions. Blood loss can also be reduced by giving hypotensive anesthesia. Rarely major eye injuries, including blindness, are seen. Visual disturbances can occur due to the eye muscle imbalance after orbital mobilization. Ptosis and diplopia can also occur postoperatively, but this usually self-corrects. A quite difficult problem to correct postoperatively is canthal drift, which can be managed best by carefully preserving the canthal tendon attachments as much as possible. Despite the extensiveness in these procedures, mortality is rarely seen in operative correction of hypertelorism.

WAGR syndrome is caused by a mutation on chromosome 11 in the 11p13 region. Specifically, several genes in this area are deleted, including the PAX6 ocular development gene and the Wilms' tumour gene (WT1). Abnormalities in WT1 may also cause genitourinary anomalies. Mutations in the PAX6 gene have recently been shown to not only cause ocular abnormalities, but also problems in the brain and pancreas.

The gene for brain-derived neurotrophic factor (BDNF), located on 11p14.1, has been proposed as a candidate gene for the obesity and excessive eating in a subset of WAGR patients. This strengthens the case for a role for BDNF in energy balance.

Children with WAGR syndrome receive regular (3-4 yearly) kidney surveillance for Wilms' tumour until at least the age of 6–8 years and thereafter remain under some follow-up because of the risk of late onset nephropathy (40% of patients over the age of 12 years). Females with WAGR syndrome may have streak ovaries, which can increase the risk for gonadoblastoma. Malformations of the vagina and/or uterus may also be present.

Blepharophimosis syndrome is an autosomal dominant characterized by blepharophimosis (horizontal shortening of the palpebral fissures), ptosis (upper eyelid drooping, usually with the characteristics of congenital ptosis), epicanthus inversus (skin folds by the nasal bridge, more prominent lower than upper lid), and telecanthus (widening of the distance between the medial orbital walls). This syndrome is caused by mutations in the FOXL2 gene, either with premature ovarian failure (BPES type I) or without (BPES type II). It may also be associated with lop ears, ectropion, hypoplasia of superior orbital rims, and hypertelorism.

Because hypertelorism is an anatomic condition associated with a heterogeneous group of congenital disorders, it is believed that the underlying mechanism of hypertelorism is also heterogeneous. Theories include too early ossification of the lower wings of the sphenoid, an increased space between the orbita, due to increasing width of the ethmoid sinuses, field defects during the development, a nasal capsule that fails to form, leading to a failure in normal medial orbital migration and also a disturbance in the formation of the cranial base, which can be seen in syndromes like Apert and Crouzon.

There have been 30 cases of Marden-Walker Syndrome reported since 1966. The first case of this was in 1966 a female infant was diagnosed with blepharophimosis, joint contractures, arachnodactyly and growth development delay. She ended up passing at 3 months due to pneumonia.

The inheritance of Impossible syndrome is suspected to be autosomal recessive, which means the affected gene is located on an autosome, and two copies of the gene - one from each parent - are required to have an infant with the disorder.

Congenital fibrosis of the extraocular muscles, or CFEOM, is a class of rare genetic disorders affecting one or more of the muscles that move the eyeballs. Individuals with CFEOM have varying degrees of ophthalmoplegia (an inability to move the eyes in one or more directions) and ptosis. The condition is present from birth and non-progressive, runs in families, and usually affects both eyes similarly. In the most common form, the superior recti are dysfunctional and the inferior recti, lacking proper opposition, pull the eyes down, forcing the head to be tilted upward in order to see straight ahead.

There are three types of CFEOM, numbered 1-3. CFEOM1, the most common type, is now known to be caused by one of several mutations in the KIF21A gene, while CFEOM2 is caused by mutations in the PHOX2A gene. CFEOM3 is caused by mutations in the TUBB3 gene.

CFEOM was first named in 1956, although papers describing conditions now known or assumed to be CFEOM appear in the medical literature as early as 1840. Due to its rarity, it has been independently cited numerous times under many different names.

A 1998 review noted that life expectancy is usually normal, but that there have occasionally been reported neonatal deaths due to PCD. A 2016 longitudinal study followed 151 adults with PCD for a median of 7 years. Within that span, 7 persons died with a median age of 65.

Parry–Romberg syndrome appears to occur randomly and for unknown reasons. Prevalence is higher in females than males, with a ratio of roughly 3:2. The condition is observed on the left side of the face about as often as on the right side.

Sensenbrenner syndrome (OMIM #218330) is a rare (less than 20 cases reported by 2010) multisystem disease first described in 1975. It is inherited in an autosomal recessive fashion, and a number of genes appear to be responsible. Three genes responsible have been identified: intraflagellar transport (IFT)122 (WDR10), IFT43 — a subunit of the IFT complex A machinery of primary cilia, and WDR35 (IFT121: TULP4)

It is also known as Sensenbrenner–Dorst–Owens syndrome, Levin Syndrome I and cranioectodermal dysplasia (CED)

Horner's syndrome is acquired as a result of disease, but may also be congenital (inborn, associated with heterochromatic iris) or iatrogenic (caused by medical treatment). Although most causes are relatively benign, Horner syndrome may reflect serious disease in the neck or chest (such as a Pancoast tumor (tumor in the apex of the lung) or thyrocervical venous dilatation).

Causes can be divided according to the presence and location of anhidrosis:

- Central (anhidrosis of face, arm and trunk)

- Syringomyelia

- Multiple sclerosis

- Encephalitis

- Brain tumors

- Lateral medullary syndrome

- Preganglionic (anhidrosis of face)

- Cervical rib traction on stellate ganglion

- Thyroid carcinoma

- Thyroidectomy

- Goiter

- Bronchogenic carcinoma of the superior fissure (Pancoast tumor) on apex of lung

- Klumpke paralysis

- Trauma - base of neck, usually blunt trauma, sometimes surgery.

- As a complication of tube thoracostomy

- Thoracic aortic aneurysm

- Postganglionic (no anhidrosis)

- Cluster headache - combination termed Horton's headache

- An episode of Horner's syndrome may occur during a migraine attack and be relieved afterwards

- Carotid artery dissection/carotid artery aneurysm

- Cavernous sinus thrombosis

- Middle ear infection

- Sympathectomy

- Nerve blocks, such as cervical plexus block, stellate ganglion or interscalene block

SCS is the most common craniosynostosis syndrome and affects 1 in every 25,000 to 50,000 individuals. It occurs in all racial and ethnic groups, and affects males and females equally. If a parent carries a copy of the SCS gene mutation, then there is a 50% chance their child will also carry a copy of the gene mutation, in which case, the child may or may not show signs of SCS. There is also a 50% chance their child will have two working copies of the gene, and would therefore, not have SCS. If both parents carry a single copy of the SCS gene mutation, then there is a 25% chance their child will have two gene mutation copies (so child would develop severe SCS), a 25% chance their child would have two normal copies of the gene (so would be completely normal), and a 50% chance their child would carry one gene mutation copy and 1 normal copy (so child may or may not display SCS). In rare situations, two normal parents can have a child with SCS due to a "de novo" mutation. The exact cause of the "de novo" mutation is unknown, but it doesn't seem to be related to anything that the parents did or didn't do during the pregnancy. SCS due to a "de novo" mutation is so rare that the proportion of past cases is unknown.

Inverse Marcus Gunn phenomenon is a rare condition that causes the eyelid to fall upon opening of the mouth. In this case, trigeminal innervation to the pterygoid muscles of the jaw is associated with an inhibition of the branch of the oculomotor nerve to the levator palpebrae superioris, as opposed to stimulation in Marcus Gunn jaw-winking.

Michels syndrome is a syndrome characterised by intellectual disability, craniosynostosis, blepharophimosis, ptosis, epicanthus inversus, highly arched eyebrows, and hypertelorism. And vary in other symptoms such as asymmetry of the skull, eyelid, and anterior chamber anomalies, cleft lip and palate, umbilical anomalies, and growth and cognitive development.

The only treatment for MWS is only symptomatic, with multidisciplinary management

Von Graefe's sign is the lagging of the upper eyelid on downward rotation of the eye, indicating exophthalmic goiter (Graves' Disease). It is a dynamic sign, whereas lid lag is a static sign which may also be present in cicatricial eyelid retraction or congenital ptosis.

A pseudo Graefe's sign (pseudo lid lag) shows a similar lag, but is due to aberrant regeneration of fibres of the oculomotor nerve (III) into the elevator of the upper lid. It occurs in paramyotonia congenita.

A pseudo Graefe's sign is most commonly manifested in just one eye but can occasionally be observed in both. The reason only one eye is affected is not yet clear.

Blepharochalasis is idiopathic in most cases, i.e., the cause is unknown. Systemic conditions linked to blepharochalasis are renal agenesis, vertebral abnormalities, and congenital heart disease.

It is encountered more commonly in younger rather than older individuals.

Most people with the disease need laser repairs to the retina, and about 60 per cent need further surgery.

Impossible Syndrome, or Chondrodysplasia situs inversus imperforate anus polydactyly, is a complex combination of human congenital malformations (birth defects).

The malformations include chondrodysplasia (improper growth of bone and cartilage), situs inversus totalis (chest and abdominal organs all a mirror image of normal), cleft larynx and epiglottis, hexadactyly (six digits) on hands and feet, diaphragmatic hernia, pancreatic abnormalities, kidney abnormal on one side and absent on the other side, micropenis and ambiguous genitalia, and imperforate anus.

Only one case of Impossible Syndrome has been reported; the infant was premature and stillborn.