Congenital cataract

Congenital cataracts are a major cause of blindness with early detection the most important factor in reducing impact on future vision.

Epidemiology

Incidence is ~3 per 100,000 in the United Kingdom . Although the incidence tends to be higher in areas with increased rates of congenital infection .

Risk factors

• low birth weight prematurity

Pathology

Congenital cataracts may be unilateral or bilateral .

Etiology

There are over 50 causes of congenital cataracts. Some common causes include:

• idiopathic (~50%) 
• hereditary e.g. trisomy 21 (Down syndrome), trisomy 13, Lowe syndrome
• infection, e.g. rubella, VZV, cytomegalovirus, HSV, toxoplasmosis
• metabolic, e.g. galactokinase deficiency

Radiographic features

Ultrasound

• assessment of the lens is recommended on second-trimester anomaly scans
• lens will appear echogenic

MRI

The MRI features of congenital cataract include :

• increase thickness of the lens(es) > 4 mm
• low signal on T1
• high signal on T2

Treatment and prognosis

Congenital cataracts that cause significant visual disturbance are treated early with surgery .