Imaging of the Pediatric Orbit

Congenital Malformations of the Eye: A Pictorial Review and Clinico-Radiological Correlations

“…Eye embryological development spans across embryonic and fetal stages [ 7 ] and continues after birth, with posterior segment expansion accounting for over 90% of postnatal growth [ 9 ]. Eye development starts at approximately day 22 of gestation when the primary optic vesicle arises from the diencephalic forebrain wall [ 10 , 11 ] and subsequently enlarges and invaginates into the secondary optic vesicle [ 10 ].…”

“…Eye development starts at approximately day 22 of gestation when the primary optic vesicle arises from the diencephalic forebrain wall [ 10 , 11 ] and subsequently enlarges and invaginates into the secondary optic vesicle [ 10 ]. This one consists of two layers: the internal retinal pigmented layer and the external retinal nervous layer [ 7 , 11 ]. At the beginning of the fourth week, the optic vesicle induces the surface ectoderm to form the lens placode [ 11 ], which transits to the lens vesicle by the 5 th week of gestation [ 10 ].…”

“…At the same time, the choroid and sclera originate from the surrounding mesenchyme, while the vitreous body originates from the mesenchyme located in the space between the lens vesicle and the secondary optic vesicle [ 10 ]. By the 35 th week of gestation, the primitive vascular system, forming the primary vitreous and consisting of the hyaloid artery and its branches, is involved, and the secondary vitreous takes its place [ 7 ]. Development and differentiation of the retinal nervous layer last until the 8 th month of gestation, when the eye becomes sensitive to light and axons from the retinal neurons extend to the brain, forming the optic nerve.…”

“…However, a tailored MRI may be of help in identifying the extreme microphthalmic globe. The exact pathogenesis remains unknown, but a comprehensive medical and familiar history, physical examination, genetic testing, and imaging may help to establish a possible, specific cause [ 7 , 11 ]. Three main types of anophthalmia have been identified: primary anophthalmia, which refers to the failure to outgrow the primary optic vesicle; secondary anophthalmia when there is the failure of development of the anterior portion of the neural tube; and tertiary or degenerative anophthalmia, in which an early injury occurred during ocular globe formation [ 6 , 10 , 21 ].…”

“…Ocular malformations represent a wide range of ocular abnormalities, with an incidence ranging from 0.36% to 4.7% [ 1 – 5 ]. Congenital ocular abnormalities may be isolated or syndromic, and the prevalence is higher in premature and stillborn children [ 4 – 7 ].…”