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Editor,—Ankyloblepharon filiforme adnatum is a rare benign congenital anomaly first described by Von Hasner in 1881.1 Fusion of the eyelid margins is a normal stage in human development but an abnormal occurrence at birth.1The developing eyelid margins remain fused until the fifth gestational month, but may not be completely separated until the seventh month.2 Ankyloblepharon is characterised by full thickness fusion of the lid margins.
Ankyloblepharon filiforme adnatum comprises single or multiple fine bands of extensile tissue connecting the lid margins at the grey line and it reduces the palpebral fissure by interfering with the movements of lids.
The abnormality has been reported as an isolated finding, in association with other anomalies or as a part of a well defined syndrome.
A 7lb 5oz (3317 g), white female baby was born at 40 weeks’ gestation to a 26-year-old third gravida. The pregnancy was normal and the mother denied having taken any drugs or being exposed to x rays. The previous two siblings, aged 4 and 2 years, both males, were healthy. There was no family history of congenital anomalies or consanguinity.
The baby was noted to have fused left eyelids at birth; apart from this she was perfectly healthy. A detailed paediatric assessment failed to reveal any other congenital abnormalities.
A more detailed ophthalmic examination showed that there was a single adhesion between the eyelids margins of the left eye (Fig 1). The lids could be easily parted to reveal an underlying normal eye. Ocular motility, anterior segment, and fundus were normal. This adhesion was extensible and was divided by a No 15 blade. There was minimal bleeding. At her follow up appointment 4 months later no abnormality was noted.
This was the third case of isolated ankyloblepharon filiforme adnatum seen at our hospital in the past 15 years. The other two babies, a boy and a girl, were also completely normal apart from the ankyloblepharon filiforme adnatum. The annual birth rate is 4500, giving an incidence of 4.4 per 100 000 births.
Ankyloblepharon filiforme is usually a solitary malformation of sporadic occurrence or a part of one of three Mendelian disorders.3
In most familial cases it occurs together with cleft lip and palate, as an autosomal dominant condition in otherwise healthy relatives (MIM 106250).4 In some patients it appears as a part of Hay–Wells syndrome,4 also known as ankyloblepharon-ectodermal dysplasia-clefting syndrome (MIM 106260) or as a part of the popliteal pterygium syndrome (MIM 263650), characterised by intercrural webbing of the lower limbs.4CHANDS (curly hair-ankyloblepharon-nail dysplasia) also has it as a part of its phenotype (MIM 214350). Other reported associations include hydrocephalus, meningocele and imperforate anus,5bilateral syndactyly, cardiac problems such as patent ductus arteriosus and ventricular septal defects, ectodermal syndromes,5 and Edwards syndrome.6 The histology of these connecting strands has been shown to consist of vascularised central core surrounded by stratified squamous epithelium.7
The aetiology of this abnormality is unknown and a number of theories have been proposed. The currently accepted theory is that this condition is due to an interplay of temporary epithelial arrest and rapid mesenchymal proliferation, allowing union of lids at abnormal positions.8
The innocuous appearance of ankyloblepharon filiforme adnatum belies its clinical importance. Although it may appear as a solitary anomaly in an otherwise healthy infant, it is frequently associated with a wide range of systemic malformations. The eye itself has not been reported to be abnormal except in a recent case report where ankyloblepharon filiforme adnatum was seen to be associated with infantile glaucoma and iridogoniodysgenesis.8 The bands frequently resolve spontaneously after a few months or may be released by a simple operative procedure.4
The major practical importance of this anomaly is that when it occurs, it should alert the physician to the possible presence of other congenital problems.