Euryblepharon is characterised by increased vertical separation of the temporal aspect of the palpebral fissure so that the palpebral conjunctiva is not in apposition with the eye. The enlargement of palpebral fissure is accompanied by variable degree of lower eyelid ectropion. The lower eyelid ectropion is caused by vertical shortening of the lower eyelid relative to the horizontal dimensions of the opposing upper eyelid. In euryblepharon, palpebral apertures are larger than normal and it may be associated with epicanthus. Widening of palpebral fissure may give the appearance of eyelid ptosis. The eyelids are normally developed but the insertions of the canthal tendons appear to be widely or anteriorly placed. Frequently, the palpebral fissure has downward slant as well because of an inferiorly displaced attachment of the lateral canthal tendon.
Euryblepharon is present at birth and there is no other associated primary ocular abnormality. In contrast, secondary enlargement of the palpebral aperture may accompany a variety of ocular abnormalities.
This condition was first described by Desmarres (1854). The average length of the lid fissures at different ages is given by Duke-Elder and Cook (1963). It increases from 18.35 mm. at birth to 29.68 mm. at 24 to 26 years of age. One half of this increase occurs in the first 4 years of life. The length is slightly less for females.
Euryblepharon may be unilateral or bilateral. It may present with
- Enlargement of horizontal palpebral apertures.
- Elongated lid margins.
- Downward and lateral displacement of outer canthus.
- Lateral ectropion.
- Watering or epiphora.
- Reduced blink rate.
- Exposure keratopathy.
Euryblepharon may be inherited as an autosomal dominant disorder or may occur sporadically.
A variety of systemic conditions may be associated such as
- Kabuki syndrome: Kabuki syndrome, described in 1981, is an idiopathic multisystem disorder characterised by characteristic facial features, short stature, mental retardation, and skeletal abnormalities. This is a clinical diagnosis of uncertain aetiology. Most cases are sporadic, but multiple familial cases suggest autosomal dominant inheritance. Clinical features include euryblepharon, depressed nasal tip, prominent cupped ears and arched eyebrows. Other ocular abnormalities may also be present. Systemic abnormalities include cleft lip/palate, kidney or urinary tract anomalies, and cardiovascular disorders.
- Blepharo-cheilo-dontic (BCD) syndrome: This congenital condition is characterised by euryblepharon with ectropion of the lower eyelids, cleft lip/palate, and dental anomalies (oligodontia and conical teeth). Other ocular abnormalities reported with this disorder are lagophthalmos, ectropion,distichiasis, and ocular hypertelorism (widely apart orbits).
- Down syndrome.
Diagnosis of euryblepharon is based on clinical features.
Euryblepharon presents with
- Bilateral symmetrical enlargement of the horizontal palpebral apertures.
- Elongated lid margins. The horizontal palpebral fissure length is increased to approximately 35 mm. from the average length of 28- 30 mm.
- Vertical shortening of eyelid skin.
- Downward and lateral displacement of outer canthi.
- There is lateral ectropion, reduced blink rate, lagophthalmos, with exposure keratopathy. There may be epiphora due to exposure and reduced blink rate.
Euryblepharon may be distinguished from conditions such as
- Congenital ectropion: Congenital ectropion also has vertical shortening of eyelid skin, but there is no elongation of lid margin.
- Lower lid ptosis.
- Other causes of epiphora.
Management should be carried out under medical supervision.
Most of the cases do not require any treatment. The condition may cease to be apparent with facial growth.
Mild cases may be managed conservatively by medical means.
- Topical lubricant artificial tears: Topical lubricant artificial tears may be used to prevent ocular irritation.
Moderate degrees of euryblepharon may require surgical therapy to protect the cornea. It may involve procedures like
- Lateral tarsorrhaphy: Lateral tarsorrhaphy (joining of upper and lower eyelids) may be required for symptomatic cases.
- Lateral canthoplasty with shortening of the upper and lower eyelids laterally.
- Re-suspension of lateral canthus: Re-suspension of lateral canthus using lateral tarsal strip may be done in severe cases of euryblepharon causing epiphora or exposure keratopathy.
- Augmentation of posterior lamella and anterior skin graft, for severe forms of vertical eyelid shortening.
Prognosis of euryblepharon may be excellent if necessary surgery for eyelid mal-position is performed to protect ocular surface.
Bowling Brad. Kanski’s Clinical Ophthalmology- A Systematic Approach Eighth Edition. Elsevier Limited 2016. P 61.
Garg Ashok, Rosen Emanuel, Mortensen Jes, Toukhy Essam El, Dhaliwal Ranjit S. Instant Clinical Diagnosis in Ophthalmology- Oculoplasty and Reconstructive Surgery. Jaypee Brothers Medical Publishers (P) Ltd 2008. P 20.
Basak Samar K. Atlas of Clinical Ophthalmology Second Edition. Jaypee Brothers Medical Publishers (P) Ltd 2013. P 6.
Wright Kenneth W, Spiegel Peter H. Pediatric Ophthalmology and Strabismus Second Edition. Springer Science+ Business Media New York 2003. P 301.
Katowitz James A. Pediatric Oculoplastic Surgery. Springer Science+Business Media New York 2002. P 213- 214.