The term cryptophthalmia is used to describe a hidden eye with no recognisable lid structures. Cryptophthalmia has been divided into three types. In the first, typical and complete form, eyelids are absent; there is a small depression in the skin where lids would normally be located; eyebrows are poorly developed or absent; a tongue of hair from the anterior hairline extends forward to fuse with the malformed brow; eyelashes, Meibomian glands, and lacrimal apparatus are absent; the underlying eye is usually dysplastic and there is no conjunctival sac. In the second, incomplete or atypical, form there are rudimentary lid structures, the eye is generally microphthalmic and covered by skin. The third and least severe form is associated with an upper eyelid which is fused to the superior aspect of the globe, does not carry lashes, and continues over the cornea as an epidermal membrane. The lower lid is normal but may lack a lacrimal punctum. The globe is generally of normal size. All three forms may be part of a spectrum of abnormality rather than separate entities, since the two eyes may manifest different forms. The palpebral fissure forms in the sixth month of gestation after the upper and lower eyelids have developed their complements of tarsus, Meibomian glands and lashes. Development of the eyelids begins during the second month of gestation, after the rudimentary corneal epithelium and endothelium have formed. Circular folds of mesenchyme, the frontonasal and maxillary processes, gradually encircle the protruding eye. These folds, which are covered by surface ectoderm on both sides, constitute the rudiments of the upper and lower eyelids. The folds move together by differential growth, contact each other by the 10th week, and become fused together by an epithelial seal. The fused lids separate between weeks 19 and 20. Eyelid opening may be the result of keratinisation or programmed cell death. The pathogenesis of cryptophthalmia is uncertain. Cryptophthalmia may occur secondary to failure of cell death or failure of keratinisation at the palpebral fissure. It may be the sequela of abnormal lens development with faulty induction of lid structures, in which case, the lid abnormalities would already be present by 10 weeks, when lid fusion occurs. Fusion of eyelids and obliteration of the conjunctival cul-de-sac may result from intrauterine inflammation or necrosis (ankyloblepharon by ankylosis). Lastly, there may be disturbance of the normal growth pattern of eyelid mesoderm in the presence of normal growth of eyelid ectoderm.


The bony orbits are reliably imaged when scanning the fetal face from the twelfth week onward, although care must be taken to avoid tangential cuts through the orbits. The optimal view of the fetal eyes on transvaginal ultrasonography is a transverse section of the fetal skull at the orbital plane. The eyes within the bony orbits are detected as bilateral hypoechoic circles superolateral to the nasal bones. Using transabdominal ultrasound, with the head in the occipitotransverse position, the transducer can be placed in two possible planes, firstly, along the coronal plane, approximately 2 cm posterior to the glabella-alveolar line, or secondly, along the orbitomeatal line, approximately 2 to 3 cm below the level of the biparietal diameter. In both these views, the midline, orbital rings, nasal processes, and portions of the maxilla can be demonstrated. With the head in the occipitoposterior position, a biparietal diameter cannot be obtained. However, the orbits can be identified and measured with the transducer placed in a plane that transects the occiput, orbits and nasal processes. Ultrasound diagnosis of cryptophthalmia has not been reported, even when a previous affected family member raises the suspicion of the diagnosis. In these families, diagnosis of cryptophthalmia has been predicated on the presence of associated features, such as microphthalmia, anophthalmia, colobomatous eye defects, abnormalities of eye spacing, or the features of the recessive cryptophthalmia or Fraser syndrome, which include oligohydramnios, non visualisation of the kidneys, renal dysplasia, facial clefting, intrauterine growth restriction and syndactyly.

Differential Diagnosis

Ankyloblepharon filiforme presents with fully formed eyelids which are held together by multiple skin filaments.

Sonographic Features

The presence of anophthalmia or microphthalmia should raise the possibility of cryptophthalmia, and lead to scrutiny of the lid area.

A search should be made for associated anomalies such as oligohydramnios, non-visualisation of the kidneys, renal dysplasia, facial clefting, intrauterine growth retardation or syndactyly.

Associated Syndromes

  • Fraser
  • Isolated


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  2. Thomas IT, Frias JL, Sanchez de Leon L, Hernandez RA, Jones MC Isolated and syndromic cryptophthalmos Am J Med Genet 25: 85-98
  3. Schauer GM, Dunn LK, Godmilow L, eagle RC Jr, Knisely AS Prenatal diagnosis of Fraser syndrome at 18.5 weeks gestation, with autopsy findings at 19 weeks Am J Med Genet 37: 583-591
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