ABSTRACT
Embryonic development of the vertebrate eye begins with the formation of an optic vesicle which folds inwards to form a double-layered optic cup with a fissure on the ventral surface, known as the optic fissure. Closure of the optic fissure is essential for subsequent growth and development of the eye. A defect in this process can leave a gap in the iris, retina or optic nerve, known as a coloboma, which can lead to severe visual impairment. This review brings together current information about genes and pathways regulating fissure closure from human coloboma patients and animal models. It focuses especially on current understanding of the morphological changes and processes of epithelial remodelling occurring at the fissure margins.
Subject(s)
Coloboma/embryology , Eye/embryology , Optic Disk/embryology , Vision Disorders/embryology , Animals , Coloboma/genetics , Eye/metabolism , Gene Expression Regulation, Developmental , Humans , Morphogenesis/genetics , Optic Disk/metabolism , Signal Transduction/genetics , Vision Disorders/geneticsABSTRACT
Congenital eye malformations are the second most common cause of childhood blindness and are originated by disruption of the normal process of eye development during embryonic stage. Their etiology is variable, although monogenic causes are of great importance as they have a high risk of familial recurrence. Included among the most severe congenital eye abnormalities are microphthalmia, defined by an abnormally small eye, and anophthalmia, characterized by congenital absence of ocular structures. The currrent knowledge of the genes involved in human microphthalmia and anophthalmia in humans is revised in this work.
Subject(s)
Anophthalmos/genetics , Microphthalmos/genetics , Child , Eye Abnormalities/genetics , Gene Expression Regulation, Developmental , HumansABSTRACT
Uveal coloboma is a rare eye malformation caused by failure of the optic fissure to close during the fifth to seventh weeks of foetal life. The risk of retinal detachment increases with age in colobomatous eyes. Preventive measures such as early detection of the retinal break, prophylactic laser photocoagulation along the coloboma margin, confer a significant benefit in reducing this risk of retinal detachment. Difficulties linked to the diagnosis and management of uveal colobomas in developing countries setting are presented in this study.