What is Congenital Cataract?
A cataract is an opacity in the crystalline lens that sits within the eye. The most common sort of cataract is one that develops with age and relates in cataract surgery in patients between the ages of 60 and 90.
A congenital cataract is a cataract which children are born with.
What causes a Congenital Cataract?
There are a number of different causes for congenital cataract. Congenital cataract can run in families (with an autosomal dominant inheritance pattern). It may be caused by metabolic abnormalities with the way compounds are dealt with in the body. They can be caused by infections, such as rubella. Cataracts may have no obvious cause.
How do patients present?
Children are tested for the appearance of a red reflex in their eyes at birth and at the six week check. The red reflex is exactly the same phenomenon that is seen using a flash photograph where the redness of the retina is reflected back through the pupil giving a “red eye” on photographs.
Cataract can sometimes be diagnosed by an asymmetry of the red reflex on photographs. The other significant and worrying cause for an abnormality in red reflex is a tumour in the back of the eye called a retina blastoma. It is essential that children who have an abnormal or asymmetric red reflux be tested for this condition.
How is Congenital Cataract treated?
Some metabolic conditions that cause cataract can be treated and the cataract will then spontaneously go away. The vast majority however will require some surgery to remove them. Surgery for cataracts should be performed very early in life. In children who have only one congenital cataract, this surgery should be performed within the first two months of life in order to give the child a maximum chance of developing useful vision in the eye. If a unilateral (one sided) cataract has not had an operation by the age of 11 weeks, the chances are that the sensory deprivation amblyopia (lazy eye due to the cataract – see Amblyopia section) would be so severe as to leave the eye having very poor vision for the rest of life.
Children who have cataracts in both eyes may do better even if surgery is delayed somewhat.
How is a cataract removed?
The cataract is either removed in its entirety in the bag that the cataract sits in being removed as well or the cataract itself is removed and the bag that the cataract was sitting in is left behind. The former operation is called a lensectomy where the whole of the lens is removed and the latter is called a cataract extraction leaving the capsule bag behind.
If the capsule bag is left behind, an intraocular lens can be placed inside this bag. If a lensectomy has been performed, the strength of the lens needs to be replaced with a contact lens. Once the cataract surgery has been performed on a child there is a very intensive follow up period with vision testing, intraocular pressure testing and contact lens fitting. This is the case whether or not a lens has been inserted. It is a very intensive program with repeated frequent visits usually up to the age of 6 or 7 years.
Each individual child’s cataract is different and the approach to their care will also consequently vary. You will need to fully discuss your child’s potential cataract surgery with Mr Simmons at an appointment.
