Childhood cataract is cataract that occurs at birth or in childhood. It may be congenital or acquired.
Congenital cataracts are defined as the presence of lens opacification during childhood. About 1.14 million children in the world are blind. Cataracts are the leading cause of blindness in children.
About
Prevalence
Childhood cataracts are the primary cause of childhood blindness. Childhood cataracts make up 7.4% to 15.3% of blindness in kids. The prevalence of childhood cataracts ranges from 0.63/10,000 to 9.74/10,000 children, with a median of 1.71. This is dependent on factors like economic status but not gender or laterality. The incidence of childhood cataracts ranges from 1.8/10,000 to 3.6/10,000 children per year.
Genetics
Childhood cataracts are hereditary in 8.3% to 25% of cases. Of which, 75% of cases are inherited in an autosomal dominant fashion. The diagnosis of childhood cataracts are associated with other eye abnormalities in 27% of cases and associated with systemic abnormalities/findings in 22% of cases.
Disease
Causes
There are several causes of childhood cataracts. A few of these causes are detailed below.
Idiopathic
Most cases of childhood cataracts, both unilateral and bilateral, are idiopathic in nature.
Hereditary
Congenital cataracts are typically inherited in an autosomal dominant pattern with incomplete inheritance. There are multiple different genetic disorders associated with congenital cataracts: Norrie disease (X-linked recessive inheritance), Nance-Horan syndrome (X-linked recessive inheritance), Down's syndrome (also associated with other eye abnormalities like nystagmus and strabismus), and Lowe syndrome (X-linked inheritance).
Metabolic
One specific metabolic disorder associated with congenital cataracts is Galactosemia.
Congenital Infections
Congenital infections include Toxoplasma, Rubella, Cytomegalovirus (CMV), Herpes, and Syphilis. The most common congenital infection to cause congenital cataracts is Rubella. Rubella is especially common, with a higher incidence in India. Rubella is characterized by a triad of features: congenital cataracts, sensorineural hearing loss, and patent ductus arteriosus (a congenital heart condition).
Trauma
Trauma can cause cataracts in childhood. There are different types of traumatic injury that cause cataracts in different parts of the world. Child abuse may cause traumatic injury to the eye and cataracts. Open globe injuries are more often associated with cataracts than closed globe injuries. The leading cause of these open globe injuries are bow and arrow injuries.
Diagnosis
Cataracts in childhood are often detected via routine screening.
Signs & Symptoms
The first sign is usually leukocoria, meaning white pupil upon fundoscopic exam. Another sign is if the child has been struggling to follow objects with their eyes or has been making decreased eye contact with family members. Other general complaints associated with childhood cataracts include kids squeezing their eyes shut in response to bright lights, squinting of eyes, history of small set eyes or large set eyes, and nystagmus. Older kids are more likely to complain of the following: difficulty viewing objects at a distance, unable to view whiteboard in class, parent may notice children are bringing objects closer to their face.
History
Routine screening is the method in which cataracts are typically diagnosed in childhood. A thorough history is obtained to assist in making this diagnosis. The following are questions to consider addressing in a visit: "at what age did the symptoms begin?", "how long have the symptoms been present?", "is there a family history of childhood cataracts?", "is there a history of pregnancy complications or symptoms?", "any drug use during pregnancy?", "is there history of trauma during pregnancy?", "does the child have any other accompanying symptoms like vomiting?". A specific question regarding vomiting is asked as it may lead to increased suspicion for Galactosemia.