Causes

There are a number of reasons why a child may be born with cataracts or develop them while they're still young.

But in many cases it's not possible to determine the exact cause.

Some of the main causes of childhood cataracts are described below.

Genes and genetic conditions

Cataracts present from birth (congenital cataracts) are sometimes caused by a faulty gene being passed to a child from their parents.

This fault means that the lens doesn't develop properly.

It's estimated there's a family history of congenital cataracts in around 1 in every 5 cases of the condition.

Recent research suggests genetic causes are responsible for the majority of bilateral congenital cataracts in the UK.

Cataracts can also be associated with conditions caused by chromosome abnormalities, such as Down's syndrome.

Chromosomes are the parts of the body's cells that carry the genes.

Congenital cataracts can also be caused by infections caught by the mother during pregnancy.

The main infections linked to an increased risk of congenital cataracts include:

rubella (german measles) – a viral infection that can cause a red-pink spotty skin rash
toxoplasmosis – a parasitic infection caught by consuming food, water or soil contaminated with infected cat's faeces
cytomegalovirus (CMV) – a common virus that can cause flu-like symptoms
chickenpox – a mild but highly infectious condition caused by the varicella-zoster virus
herpes simplex virus – a virus that often causes cold sores

Cataracts that develop in children after they're born are known as acquired, infantile or juvenile cataracts.

Causes of this type of cataracts can include:

galactosaemia – where the sugar galactose (which mainly comes from lactose, the sugar in milk) can't be broken down by the body
diabetes – a lifelong condition that causes a person's blood sugar level to become too high
eye trauma – as a result of an injury to the eye or eye surgery
toxocariasis – a rare parasitic infection that can sometimes infect the eyes, spread from animals to humans via their infected faeces

But most of these problems are either rare or don't usually cause cataracts to develop in children.

Page last reviewed: Mon Oct 2021 Next review due: Wed Feb 2020