Medical expert of the article
New publications
Megalocornea and microcornea
Last reviewed: 07.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Since various tissues of the anterior segment of the eyeball are exposed to the same influences, congenital corneal pathology is often combined with pathological changes in the iris and/or glaucoma.
Despite the specificity of clinical manifestations of the disease for each individual structure, there are common features in all cases. Genetic predetermination of the occurrence of isolated lesions of the anterior segment or a combination of developmental anomalies of the visual organ with general pathology is possible. Developmental disorders also occur as a result of toxic damage (including fetal alcohol syndrome).
[ Megalocornea
Megalocornea is defined as a condition in which the horizontal diameter of the cornea exceeds 13 mm and does not tend to increase further. Intraocular pressure is within normal limits. The structure and thickness of the cornea are usually unchanged. Other manifestations of this bilateral syndrome may include arcus juvenilis, mosaic corneal dystrophy, pigment spraying, cataracts, and lens subluxation. The predominant type of refraction is low-grade myopia and astigmatism, as well as emmetropia. In most cases, visual development does not deviate from the norm. Most often, the disorder has an X-linked type of inheritance; the pathological gene is localized on the long arm of the X chromosome in the region Xql2-q26. Autosomal recessive and autosomal dominant types of inheritance have been reported.
Megalocornea may be combined with such common diseases as:
- ichthyosis and congenital poikiloderma;
- Aarskog syndrome - an X-linked recessive disorder characterized by short stature, hypertelorism, antimongoloid eye slant, scrotal malformation, and syndactyly;
- Marfan syndrome;
- mental retardation syndrome with megalocornea - mental retardation, short stature, ataxia and seizures;
- Kneist syndrome;
- diabetes insipidus.
Concomitant pathology of the visual organ:
- ectopia lentis et pupillae is a condition with an autosomal recessive type of inheritance, characterized by the presence of a persistent pupillary membrane, a backward displacement of the lens, cataracts, myopia, and an increased risk of retinal detachment;
- congenital miosis;
- Rieger syndrome;
- albinism;
- Weill-Marchesani syndrome;
- Crouzon syndrome;
- Marshall-Smith syndrome - developmental delay, mental retardation and dysmorphia;
- dwarfism syndrome - short stature, loose joints, delayed development of the visual organ and teeth, Rieger's anomaly.
Microcornea
Microcornea is a rare condition in which the cornea diameter does not exceed 10 mm, and the parameters of the anterior segment of the eyeball are usually reduced, with the dimensions of the posterior segment remaining unchanged.
Microcornea may be accompanied by corneal opacities and vascularization, anterior segment dysgenesis, cataracts, congenital aphakia, coloboma, persistent vitreous hyperplasia (PVH), retinal dysplasia, and ipsilateral facial malformations.