Sclero-cornea and defective mesodermal migration

Overview of sclerocornea

Sclerocornea is a rare non-progressive, non-inflammatory usually bilateral congenital corneal opacity that can be associated with both ocular and systemic abnormalities. It could be inherited in 50% of cases. Ill-defined limbal architecture and vascularization in association with ocular comorbidities results in poor outcomes with corneal transplantation. This narrative review summarizes the current literature on etiology and clinical presentation in sclerocornea. With regards to keratoplasty, it focusses on key elements in decision making, highlights the role of investigations and discusses practical surgical pearls to enhance outcome of keratoplasty in these eyes.

Congenital corneal keloid

The clinical course and pathological findings in an infant with a congenital corneal opacity, aniridia, and cataract of the right eye and anophthalmia of the left orbit are reviewed. Although the lesion was thought to represent a dermoid pre-operatively, the keratoplasty specimen revealed disorganized and vascularized connective tissue, with thickened, keratinized epithelium. Bowman's and Descemet's membranes as well as the endothelium were absent. These histopathologic findings were felt to represent a congenital corneal keloid. The co-existence of aniridia in the involved eye and anophthalmia of the contralateral socket are hypothesized to be evidence that a primary ocular developmental disorder, rather than a reparative process, resulted in the corneal alteration. The difficulties of penetrating keratoplasty in lesions of this sort are examined.

Sclerocornea associated with the chromosome 22q11.2 deletion syndrome

Reported ocular findings in the 22q11.2 deletion syndrome (which encompasses the phenotypes of DiGeorge, velocardiofacial, and Takao (conotruncal-anomaly-face) syndromes) have included posterior embryotoxon (prominent, anteriorly displaced Schwalbe's line at the corneal limbus or edge), retinal vascular tortuosity, eyelid hooding, strabismus, and astigmatism. We present seven 22q11.2 patients from multiple centers with sclerocornea, an eye finding previously unreported in the literature. Four boys and three girls were identified with sclerocornea, systemic DGS/VCFS findings, and fluorescence in situ hybridization (FISH)-confirmed microdeletion at chromosome 22q11.2. FISH diagnosis was perinatal in six patients but at 2 years of age in one child. Sclerocornea was bilateral in five patients. Findings included descemetocele (five eyes), microophthalmos (one eye), iridocorneal adhesions (one bilateral case), and severe anterior segment dysgenesis (one eye). Two patients underwent bilateral corneal transplantation; another two were scheduled for possible unilateral transplant. Sclerocornea is a static congenital condition in which the cornea is opaque and vascularized and resembles the sclera. The novel finding of sclerocornea suggests that a genetic locus at 22q11.2 may be involved in anterior segment embryogenesis. In most of our patients, the diagnostic process was underway, but in one patient 22q11.2 deletion was not suspected until after the child had already been undergoing treatment for sclerocornea for 2 years. Sclerocornea should be added to the clinical manifestations of the 22q11.2 deletion syndrome. Ophthalmologists diagnosing sclerocornea in children with systemic findings suggestive of 22q11.2 deletion should ensure appropriate genetic referral.

Corneal Perforation in a Premature Infant

BACKGROUND

Few cases of corneal perforation in a premature infant have been described in the literature.

METHODS

Identical twins were born at 30-weeks gestation. One twin developed a corneal epithelial defect, infiltration, and perforation with extrusion of intraocular contents, requiring an emergency penetrating keratoplasty. The second twin developed a progressive corneal opacity, requiring a lamellar keratectomy.

RESULTS

After penetrating keratoplasty, the patient developed absolute glaucoma with buphthalmos, leading to enucleation. The twin's lamellar keratectomy specimen proved to be a dermoid.

CONCLUSIONS

One must be aware of the danger of the development of spontaneous corneal perforation with extrusion of intraocular contents in premature infants presenting at birth with an epithelial defect.

A rare case of bilateral congenital corneal malformations

We report the case of a now 6-year-old girl who was born with different abnormalities in each eye. The right eye showed a total sclerocornea. At the age of 4 years we performed a perforating keratoplasty. On the left eye a large staphyloma developed. The staphyloma was excised and a cornea with a scleral rim was fixed in. This transplant became cloudy under a conjunctival flap and blepharoplasty. In addition to the clinical follow-up, histological and immun-histochemical examinations of the corneas were carried out.

Microphthalmos and anterior segment dysgenesis in a family

An unusual sibship is described of a spectrum of microphthalmos associated with various degrees of anterior segment mesodermal dysgenesis ranging from partial sclerocornea to congenital anterior staphyloma. The possible embryologic significance of these anomalies manifesting together are discussed, along with the visual benefits which are sometimes surprisingly attainable in these usually hopeless eyes.

Spontaneous corneal perforation and extrusion of intraocular contents in premature infants

Unilateral spontaneous corneal perforation with expulsion of intraocular contents is reported in two very small, high risk premature neonates. The one surviving infant demonstrated unilateral microphthalmos with aphakia and a small leukoma. The cause of this phenomenon is not clear, and measures which might be taken to prevent its occurrence are not obvious.

Phenotypic variation in the del(12p) syndrome

Previous reports suggested the existence of a del(12p) syndrome. Phenotypic abnormalities associated with del(12p) appear to be mental retardation, microcephaly, and micrognathia. The patient with del(12p) reported here was normocephalic and large for gestational age. She probably had sclerocornea, a finding not previously associated with del(12p). Phenotypic variation in del(12p) syndrome is probably caused by differences in the size of the deleted segment and/or the presence or absence of mutant genes on the homologous 12p segment.

Ultrastructure and successful keratoplasty of sclerocornea in Mietens' syndrome

A 5-year-old boy with Mietens' syndrome had bilateral microsclerocornea, hypoplastic nose, bilaterally absent radii, elbow flexion contractures, absent left fibula, growth retardation, and normal intelligence. Both corneas measured 9.25 mm in diameter and showed diffuse anterior stromal opacification with focal nebular densities and extensive superficial vascularization. Penetrating keratoplasty in one eye remained clear and compact two years postoperatively and visual acuity improved. Histopathologically, vascularized collagenous tissue occupied the anterior one fourth of the corneal stroma and contained bundles of collagen fibrils 75 to 90 nm in diameter. Descemet's membrane showed abnormal anterior lamination.

Spontaneous corneal perforation with expulsion of the lens and retina in a premature infant

This case presents an additional ophthalmological complication in the infant under 1000 gm. The potential relationship of spontaneous corneal perforation suggests the need for extreme care in eye management in these infants.

Melnick-Needles syndrome

A 10-year-old female with a generalized bone dysplasia was found to have a rare condition, Melnick-Needles syndrome. Characteristic clinical features of this syndrome include exophthalmos, hypertelorism, micrognathia, malaligned teeth, and large ears in a person with multiple bone deformities. In addition to the usual characteristic clinical findings, sclerocornea and cornea plana were also present in this patient. This is the first case of Melnick-Needles syndrome reported in the ophthalmological literature and the first case reported with ophthalmological findings other than exophthalmos and strabismus.