Pediatric Cataract

Excerpt

Pediatric cataracts are a leading cause of treatable childhood blindness. If left unaddressed, cataracts can have substantial social, economic, and emotional consequences for the affected child, family, and broader community. Effective management remains challenging due to the critical need for early identification, diagnosis, and intervention to prevent irreversible amblyopia.

Routine screening and parental awareness of early signs, such as leukocoria and strabismus, facilitate timely diagnosis and treatment. Favorable visual outcomes depend on comprehensive preoperative assessment, accurate intraocular lens (IOL) power calculation, meticulous surgical technique, and coordinated postoperative care, including visual rehabilitation. Optimal management requires an interprofessional approach involving pediatrics, anesthesiology, ophthalmology, and optometry.

Pediatric cataracts are a major cause of preventable childhood blindness worldwide, particularly in developing countries, where delayed diagnosis often leads to advanced presentations such as nystagmus, poor fixation, and dense cataracts. Early intervention significantly improves visual outcomes and enhances the affected child’s personal and social development, while also alleviating the socioeconomic burden on families. Globally, pediatric cataracts account for approximately 5% to 20% of childhood blindness and severe visual impairment, with an estimated incidence of 1.8 to 3.6 per 10,000 children per year and a prevalence ranging from 1 to 15 per 10,000 children.

Population-based data show similar trends in high-income settings. Holmes et al reported a prevalence of 3 to 4 visually significant cataracts per 10,000 live births in the United States. A study by Rahi et al in the United Kingdom found a prevalence of 3.18 per 10,000 live births, while Nile et al reported an incidence of approximately 5 per 10,000 births in China. Despite regional differences in detection and reporting, consistent findings across studies indicate no significant laterality or sex predilection.

Hereditary congenital cataracts have a prevalence between 8.3% and 25%, with about 75% of cases following an autosomal dominant inheritance pattern. Pathogenic variants in crystallin proteins, which are essential for maintaining lens transparency and refractive function, have been associated with several cataract subtypes, including nuclear, lamellar, zonular, and posterior polar cataracts. Nonsyndromic inherited cataracts frequently involve genetic alterations in crystallin or connexin genes. PITX3 mutations are specifically linked to posterior polar cataracts, while PAX6 alterations are associated with anterior polar cataracts.

Syndromic cataracts are linked to specific genetic defects, including galactosidase-α in Fabry disease, galactose-1-phosphate uridyltransferase (GALT) in galactosemia, OCRL in Lowe (oculocerebrorenal) syndrome, and NHS in Nance–Horan syndrome, a cataract–dental disorder (see Image. Congenital Cataracts and Abnormal Galactose Metabolism). Maternal and congenital infections, particularly Toxoplasma gondii, rubella, cytomegalovirus, herpes simplex virus, and Treponema pallidum (syphilis)—collectively known as TORCH pathogens—are also major contributors to pediatric cataracts. B Mahalakshmi et al reported a high prevalence of TORCH infections in the Indian subcontinent, with 20% of cases testing seropositive. Ocular trauma is another significant cause, accounting for 12% to 46% of pediatric cataract cases.

Concerns exist regarding the higher incidence of complications, such as glaucoma, uveitis, dense posterior capsule opacification (PCO), and increased secondary interventions following primary IOL implantation in children younger than 2 years. However, primary IOL implantation in these young individuals has been shown to be safe, with excellent long-term outcomes compared to aphakia and secondary IOL implantation after age 2. The myopic shift is generally well-controlled, visual acuity outcomes are favorable, and the incidence of complications, such as glaucoma, uveitis, membrane formation, synechiae, and the need for secondary interventions, is lower than previously reported. Special care is necessary for children younger than 6 months due to the high risk of adverse events in smaller eyes.

The process of emmetropisation in children is typically complete by age 12, with axial length increasing from approximately 16.5 mm at birth to 23 mm by age 13. This growth occurs in 3 phases: the rapid phase (0.46 mm/month from birth to 6 months), the infantile phase (0.15 mm/month from 6 to 18 months), and the juvenile phase (from 18 months to 12 years).

Corneal curvature also changes significantly, with mean keratometry readings decreasing from approximately 51.2 D at birth to 43.5 D in adulthood. Consequently, the power of the IOL implanted in children must be adjusted to account for both axial elongation and the accompanying myopic shift. This adjustment requires the use of customized IOL power calculation formulas suited to growing pediatric eyes.

Sharp-edged IOLs are now widely preferred due to their association with lower rates of visual axis opacification (VAO), resulting in fewer neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomies compared to round-edged lenses (1/371 vs 4/371).

Prompt management of pediatric cataracts is essential for optimal visual development. Most children with congenital or developmental cataracts will require surgical intervention. The degree of visual impairment may be initially assessed using the red reflex during distant direct ophthalmoscopy (see Image. Red Reflex). For visually significant cataracts, bilateral cases should be treated between 6 and 8 weeks of age, while unilateral cases require earlier intervention, typically between 4 and 6 weeks.