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.

Anterior Segment Dysgenesis (ASD) represents a spectrum of rare, congenital disorders that pose significant challenges to ophthalmological management due to their complex and heterogeneous nature. The management of ASD becomes particularly complex when associated with other serious ocular conditions. This report discusses the case of a 4-year-old girl diagnosed with ASD exhibiting a combination of sclerocornea, aphakia, aniridia, and secondary glaucoma. Owing to the complexity of such condition, a multi-disciplinary approach is required. Despite successful initial surgical interventions on the left eye, eye was lost due to subsequent endophthalmitis and retinal detachment, resulting in a decision to adopt a conservative, non-surgical approach for the right eye. Although a series of therapeutic interventions have been performed, the final visual outcome was poor, demonstrating the complexity and seriousness of such cases. This case serves as a reminder of the need for regular follow-up, prompt recognition, and management of potential complications. Further research is necessary to optimize the outcomes in patients with similar presentations.

Cornea plana (CP) is a rare ocular condition existing in two distinct clinical and hereditary forms: a milder, autosomal dominant type I and a more severe, autosomal recessive type II. The condition is more commonly found in Finnish, Saudi, and Czech families. We report three brothers from a consanguineous marriage that presented with complaints of decreased vision of varying degrees. All three of them have blue, thick, and hazy corneas with shallow anterior chamber depths. The additional features of CP type II were seen in the older two brothers including arcus lipoids, ill-demarcated limbus, and an accommodative squint. They were managed by the correction of refractive errors through spectacles and detailed counseling with follow-up visits to look for progressive complications. The management is mainly centered around optically or surgically correcting the developmental anomalies. This is complimented with proper genetic counseling and regular follow-up visits to look for and manage complications. There are, however, novel therapies that can be considered in these patients including corneal transplants or corneal stromal stem cellular therapies.

Sclerocornea is a rare congenital anomaly with clouding of the peripheral cornea that possibly extends up to the center of the cornea. Characteristically, a clear distinction (limbus) between sclera and cornea is lacking. Early surgical treatment is essential for preventing amblyopia, but penetrating keratoplasty in children carries a relatively high risk of complications. Especially for sclerocornea, penetrating keratoplasty has generally been reported to have a poor surgical outcome and a high risk of complications, including corneoscleral adhesions. Here, we report the 4-year follow-up on a child with sclerocornea, who was successfully operated on at the age of 3 months and had a favorable outcome. Our findings suggest that in some cases, penetrating keratoplasty may be an option to treat sclerocornea in young children.

Penetrating keratoplasty in children is associated with very specific difficulties for the surgeon as well as for the patient and the parents. Special features are specific pediatric indications, which do not occur in adults, a more difficult examination and treatment adherence depending on the parents. Diseases with a favorable prognosis include keratoconus and herpetic keratitis. Especially sclerocornea and the Peters\' anomaly often have a limited prognosis regarding vision and graft survival due to secondary malformations of the eye. In addition, younger age represents a risk factor. This is most likely due to the impaired examination during follow-up and reduced compliance. For successful penetrating keratoplasty in children the timing for the operation, in which the risk for the graft is weighed up against the risk for amblyopia, is crucial.

This project expands the disease spectrum for mutations in GJA8 to include total sclerocornea, rudimentary lenses and microphthalmia, in addition to this gene\'s previously known role in isolated congenital cataracts. Ophthalmic findings revealed bilateral total sclerocornea in 3 probands, with small abnormal lenses in 2 of the cases, and cataracts and microphthalmia in 1 case. Next-generation sequencing revealed de novo heterozygous mutations affecting the same codon of GJA8 : (c.281G>A; p.(Gly94Glu) and c.280G>C; p.(Gly94Arg)) in 2 of the probands, in addition to the c.151G>A; p.(Asp51Asn) mutation we had previously identified in the third case. In silico analysis predicted all of the mutations to be pathogenic. These cases show that deleterious, heterozygous mutations in GJA8 can lead to a severe ocular phenotype of total sclerocornea, abnormal lenses, and/or cataracts with or without microphthalmia, broadening the phenotype associated with this gene. GJA8 should be included when investigating patients with the severe anterior segment abnormality of total sclerocornea.

Our objective is to evaluate the literature regarding selected genetic diseases of the cornea, including megalocornea, keratoglobus, keratoconus, cystinosis, the mucopolysaccharidoses, sclerocornea, Peters\' anomaly, familial dysautonomia, and various corneal dystrophies. The transparency of the cornea is a consequence of uniformity in both size and spacing of the collagen lamellae. The cornea\'s clarity depends on a delicate biochemical and structural balance; consequently, genetic disorders that disrupt either its metabolic or anatomic function can cause opacity and vision loss. Many childhood corneal diseases have a genetic etiology and are associated with known syndromes. Each disorder has unique associated set of possible complications. Prognosis often depends on the extent of opacity and disorganization of the anterior segment. Corneal transplantation has been performed for these disorders with variable success.

Van den Ende-Gupta Syndrome (VDEGS) is an autosomal recessive disorder characterized by blepharophimosis, distinctive nose, hypoplastic maxilla, and skeletal abnormalities. Using homozygosity mapping in four VDEGS patients from three consanguineous families, Anastacio et al. [Anastacio et al. (2010); Am J Hum Genet 87:553-559] identified homozygous mutations in SCARF2, located at 22q11.2. Bedeschi et al. [2010] described a VDEGS patient with sclerocornea and cataracts with compound heterozygosity for the common 22q11.2 microdeletion and a hemizygous SCARF2 mutation. Because sclerocornea had been described in DiGeorge-velo-cardio-facial syndrome but not in VDEGS, they suggested that the ocular abnormalities were caused by the 22q11.2 microdeletion. We report on a 23-year-old male who presented with bilateral sclerocornea and the VDGEGS phenotype who was subsequently found to be homozygous for a 17 bp deletion in exon 4 of SCARF2. The occurrence of bilateral sclerocornea in our patient together with that of Bedeschi et al., suggests that the full VDEGS phenotype may include sclerocornea resulting from homozygosity or compound heterozygosity for loss of function variants in SCARF2.