Pediatric Cataract

Excerpt

Pediatric cataracts are a leading cause of treatable childhood blindness. Delayed recognition and treatment are associated with substantial social, economic, and emotional consequences at the individual, familial, and community levels. Effective management remains challenging because prevention of irreversible amblyopia depends on early identification, timely diagnosis, and prompt intervention.

Population-based vision screening programs and caregiver recognition 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.

Globally, pediatric cataracts constitute a major cause of preventable childhood blindness, particularly in low- and middle-income regions, where delayed diagnosis frequently results in advanced clinical presentations, including nystagmus, poor fixation, and dense lens opacities. Early surgical intervention is associated with improved visual outcomes, enhanced functional development, and reduced long-term socioeconomic burden. Pediatric cataracts account for approximately 5% to 20% of childhood blindness and severe visual impairment worldwide, 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 US. A study by Rahi et al in the UK reported a prevalence of 3.18 per 10,000 live births, whereas 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-based predilection.

Hereditary congenital cataracts have a prevalence of 8.3% and 25%, with approximately 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. 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 α-galactosidase A 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, and increased secondary interventions following primary IOL implantation in children younger than 2. Primary IOL implantation in this age group has nevertheless demonstrated safety, 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 infants younger than 6 months because of the increased 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 proceeds in 3 phases: rapid (0.46 mm/month from birth to 6 months), infantile (0.15 mm/month from 6 to 18 months), and juvenile (0.15 mm/month 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, IOL power selection in pediatric patients must account for axial elongation and the associated myopic shift. This consideration necessitates the use of pediatric-specific IOL power calculation formulas adapted for ongoing ocular growth. Sharp-edged IOLs are now widely preferred due to an association with lower rates of visual axis opacification (VAO). Compared with round-edged lenses, sharp-edged designs result in fewer neodymium-doped yttrium aluminum garnet laser capsulotomies, occurring in 1 of 371 eyes compared with 4 of 371 eyes.

Prompt management of pediatric cataracts is essential for optimal visual development. Most children with congenital or developmental cataracts require surgical intervention. Initial assessment of visual significance may be performed 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.