Anisometropia and refractive status in children with congenital nasolacrimal duct obstruction-a prospective observational study

PURPOSE To assess the refractive status and anisometropia in children with unilateral and bilateral congenital nasolacrimal duct obstruction (CNLDO). METHODS Consecutive children newly diagnosed with CNLDO were prospectively enrolled from November 2017 to May 2019. A complete ophthalmic evaluation including cycloplegic refraction was performed followed by appropriate intervention. Patients were followed for 6 months, and cycloplegic refraction was performed at each visit. The final refractive error was defined as the refractive error obtained from the most recent visit. Amblyogenic risk factors were assessed based on 2013 referral criteria of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS). RESULTS A total of 308 patients with CNLDO were enrolled: 205 (67%) unilateral cases and 103 (33%) bilateral cases. In unilateral cases, the affected eye and unaffected fellow eye showed statistically significant difference in terms of sphere (P < 0.001), cylinder (P = 0.019), and spherical equivalent (P < 0.001); there was no interocular difference in bilateral cases (P > 0.05). Anisometropia was more prevalent in unilateral cases than in bilateral cases (11.2% vs 1.9%; P = 0.005). Based on the 2013 AAPOS referral criteria, 3.9% of the unilateral and 3.9% of bilateral cases exhibited amblyogenic risk factors. Later age of presentation was associated with higher rate of anisometropia (53.8% in the age group >48 months). CONCLUSIONS In our study cohort, unilateral CNLDO was associated with a higher prevalence of anisometropia compared with bilateral CNLDO. The affected eye in unilateral CNLDO had higher prevalence of refractive error.