Children with congenital nasolacrimal duct obstruction are at risk for amblyopia

A prospective observational study conducted in India evaluated the prevalence of anisometropia in children with congenital nasolacrimal duct obstruction (CNLDO) and assessed amblyopia risk in this population.

Study design

Three hundred eight consecutive children aged ≥2 months and newly diagnosed with unilateral or bilateral CNLDO were followed for 6 months. Regular cycloplegic refractions were performed to gauge the risk of amblyopia.

Outcomes

Two-thirds of the study participants had unilateral CNLDO. Amblyogenic risk factors, as defined by the American Association for Pediatric Ophthalmology and Strabismus 2013 referral criteria, were noted in 4% of both children with unilateral CNLDO and children with bilateral CNLDO. Anisometropia was seen more in unilateral cases (11.2%) than in bilateral cases (1.9%). Anisometropia increased in frequency with increased age at presentation, with rates ranging from 4.0% in children aged 2–30 months up to 53.8% in children aged >48 months.

Limitations

Although results from this observational study show correlation between CNLDO and amblyopia, the authors note that causation cannot be established.

Clinical significance

CNLDO affects 20% of infants globally and has been thought to be benign and without visual consequence. However, as this study shows, altered refractive development may occur in patients with CNLDO. This is hypothesized to be due to retinal image blur and defocus from increased tear lake.