Congenital anomalies of lens shape

Abstract

The crystalline lens is an important structure in the eye that starts to develop as early as the 22nd day of gestation, with further differentiation that continues after the induction. Congenital anomalies of the lens may involve the size, shape, and position of the lens. They may sometimes be associated with anterior segment dysgenesis or persistence of the tunica vasculosa lentis and hyperplastic vitreous and hyaloid system. Manifestations of anomalies of the lens shape are usually seen in early or late childhood however may sometimes be delayed into adulthood based on the level of visual impairment or the presence or absence of any syndromic associations. While lens coloboma has more often been reported in isolation, the more commonly implicated genes include the PAX6 gene, lenticonus in particular anterior is often part of Alport syndrome with extra-ocular manifestations in the kidneys and hearing abnormalities due to mutations in the alpha 5 chain of the Type IV collagen gene. Recognition of these manifestations and obtaining a genetic diagnosis is an important step in the management. The level of visual impairment and amblyopia dictates the outcomes in patients managed either conservatively with optical correction as well as surgically where deemed necessary. This review discusses the various anomalies of the lens shape with its related genetics and the management involved in these conditions.

Keywords

• crystalline lens
• lens colobomas
• lenticonus
• microspherophakia
• pax 6
• collagen iv