The congenital cataract, also known as an embryopathy, is present upon birth or within the first three months after birth. If it is very small, it may not affect vision. It sometimes progresses slowly over and begins affecting vision during infancy or as a child (childhood cataract) or even during adulthood. It may be unilateral or bilateral and may affect the whole lens or only parts of it.
Causes of the congenital cataract:
- Hereditary: Approximately 1 in every 4 cases of congenital cataract is transmitted genetically, almost always due to autosomal dominant inheritance.
- Chromosomal aberrations: Down’s Syndrome, Trisomy 18, Turner Syndrome, etc.
- X Rays during the first trimester of pregnancy, especially of the pelvic region.
- Medication taken by the mother during the first trimester: Corticosteroids, chlorpromazine and sulfonamides.
- Metabolic illnesses: Diabetes and hypothyroidism affecting the mother and galactosemia in the embryo.
- Viral infections in the first trimester: Rubella, herpes and mumps.
- Extreme maternal malnutrition.
- In the majority of cases, the cause is unknown.
Types of congenital cataract:
- Congenital capsular cataract: These are very uncommon. They are often small and do not affect vision. They are often associated with remains in the tunica vasculosa lentis (remains of the pupillary membrane and epicapiscular stars).
- Congenital polar cataract: These are more common. They affect the capsule and the subcapsular cortex. They are usually stationary, but sometimes progress and vision ends up deteriorating.
- Congenital lenticular cataract: The opacity is located in the core or in the cortex of the lens. The opacity is often characteristic and depends on the causative factors. Lamellar cataracts (also called zonular) are the most frequent, followed by pulverulent, sutural and axial cataracts.
- Congenital cataracts occasionally take on a generalised opacitywhich affects the whole lens (total or subtotal congenital cataract), causing severe visual deficiency. In these cases, early eye surgery is vital for avoiding severe amblyopia (lazy eye).