Cataracts

Congenital and infantile cataracts may be classified by their morphology, etiology, presence of specific metabolic disorders, and by associated ocular and systemic anomalies. When bilateral, approximately one-third of these cataracts occur as an inherited trait, one-third are associated with specific diseases or syndromes, and one-third are idiopathic.4

Nuclear cataracts

Nuclear cataracts may be unilateral (99, 100), but often are seen bilaterally and are associated with an autosomal dominant (AD) inheritance pattern. The location in the embryonal or fetal nucleus suggests a congenital onset, but acquired cases are also seen. They are usually dense and highly visually significant. They may be diagnosed at or shortly after birth due to an abnormal or absent red reflex and leukocoria.

Lamellar cataracts

These opacities are whitish and occupy a layer between the nucleus and cortex. The nucleus and more peripheral cortex are generally clear. The visual significance can vary widely and may be progressive (101–104). Lamellar cataracts are occasionally unilateral, but are more often bilateral. The location suggests that these opacities are usually acquired and may be a result of an intrauterine insult.

99

99 Unilateral nuclear cataract of unknown etiology in a 6-week-old infant with hypoplastic left heart syndrome.

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100 Same eye as in Figure 99 seen under operating microscope.Note the clear lens peripheral to the opacity.

Anterior polar cataracts

Anterior polar cataracts are small, white, central opacities. They derive from abnormal separation of the lens vesicle during embryogenesis. These opacities may be transmitted in an AD pattern, but over 90% are sporadic.5 They are typically 1–2 mm in size and are not progressive, although progression has been described.6 Approximately one-third are bilateral (105–107). They are not often highly visually significant, but may be associated with amblyopia due to variable degrees of anisometropia. Surgical intervention is not frequently necessary.

Posterior polar cataracts

Similar to their anterior equivalents, posterior polar cataracts are small, white, central opacities. They are often seen in association with aniridia. They may be highly visually significant, even when relatively small. Posterior lenticonus may also lead to central posterior opacities that may be similar in appearance. However, the opacities associated with posterior lenticonus may be rapidly progressive, unlike true posterior polar cataracts.