The opacities are located at the anterior and posterior Y-sutures of the embryonic nucleus. Occurring during the lens formative stage, sutural cataracts are static and present as white or blue band-shaped opacities. They are usually confined to the Y-suture and may be combined with cerulean cataract, coronary cataract, or other forms of cataracts (Fig. 6.2). It has been reported that the mutation of beaded filament structural protein 2 (BFSP2), which codes an important cytoskeleton protein BFSP, can result in sutural cataract [9]. Sutural cataract is inherited in an autosomal dominant pattern. Obvious lens opacities are presented in male patients with X-linked inheritance, while mild presentation is noted in female patients. It is visually insignificant.

One of the most common types of congenital cataracts, the lamellar cataract, is usually bilateral, disk-like and static, which affects certain layers of the lens. The size of the opaque disk corresponds to the diameter of the lens at the age of onset. If the cataract occurs at birth, the disk measures around 6.5 mm in diameter. A circle of shell-like white opacities composed of fine white dots around the fetal nucleus can be seen via slit-lamp biomicroscopy. Sometimes the lamellar opacities are not complete; thus, the wedges formed by transparent fibers can be observed within the shell-like opacities. It can be combined with V-shaped opacities that wrap around the edge of the lamellar opacities called cortical riders (Fig. 6.3). The cortical rider is separated from the disk-shaped opacities by a transparent layer. Because the center of the lens nucleus remains transparent, visual prognosis is good with lamellar cataracts. In clinical practice, the age of onset can be inferred from the association between the opacity layer and fetal nucleus. If the opacities encircle the fetal nucleus, congenital cataract may be considered, and if the opacities encircle the adult nucleus, then acquired cataract may be considered. Most lamellar opacities are congenital and generally inherited as an autosomal dominant trait, with only a minority of cases being inherited in a recessive fashion or as a result of rubella infection during pregnancy. Congenital lamellar cataract can be caused by the mutations of CRYAA and CRYGC, which code the major structural proteins of the lens, αA- and γC-crystallins [10, 11]. Moreover, BFSP2 mutation can also lead to lamellar cataract [12].

Metabolic factors after birth can also cause lamellar cataracts, which present as fine white dots surrounding the adult nucleus and are characteristically without cortical riders. It is common in Type 1 diabetes or galactosemia. If these causative factors can be addressed promptly, the cataract will not develop further.

Pediatric nuclear cataracts are observed in congenital and secondary cases. The morphology is characterized by opacities of gray dots in the embryonic and fetal nuclei. The congenital nuclear cataract can be caused by the mutations of CRYAA, CRYBB2, and CRYGC, which code αA-, βB-, and γC-crystallins, respectively, largely inherited in an autosomal dominant pattern [13–15] (Fig. 6.4).

The coralliform cataract features disk-, tube-, or oval-shaped white or gray opacities in the embryonic nucleus. They form a radiating pattern or an irregular stack toward the anterior capsule like a forward-growing coral, hence the name coralliform cataract (Fig. 6.5). This type of cataract can affect vision and is generally static. Most pediatric cases have a family history of cataracts, inherited as autosomal dominant or recessive pattern. Previous study has demonstrated that CRYGD mutation can induce coralliform cataract, which code γD-crystallin [16].

The central pulverulent cataract is caused by affection to the embryonic nucleus during the first three months of gestation, without involvement of the fetal nucleus. It is characterized by fine white dots or pulverulent opacities confined between the Y-sutures. The opacities only occur in part of the embryonic nucleus in the form of scattered fine pulverulent granules (Fig. 6.6), unlike the homogeneous and dense opacities seen in the nuclear cataract. The central pulverulent cataract is generally bilateral and static and does not impair vision significantly.

Cerulean cataracts feature opacities of irregular and sporadic blue dots in the fetal nucleus or adult nucleus (Fig. 6.7). The blue dots are generally 0.1–0.2 mm in diameter. They are static and bilateral [17], with normal or slightly affected vision. They are noted in congenital or acquired cataracts. The congenital cerulean cataract can also be caused by CRYGD mutation [18].