To identify causes of conditions presenting with low vision without distinct abnormities in pediatric patients and to determine the appropriate diagnostic approach for those conditions.

We retrospectively reviewed medical records of pediatric patients with amblyopia, suspicious amblyopia or visual impairment of unknown origin referred by primary care providers. Patients were classified into 2 groups, amblyopia and visual impairment of unclear origin. In this study, we reviewed and analyzed the visual impairment of unclear origin.

Of 152 patients, 94 patients were classified as amblyopia and 58 patients were classified as visual impairment of unclear origin. Among those with visual impairment of unclear origin, 26 patients (44.8%) were classified as functional visual loss, 23 patients (39.7%) as normal corrected visual acuity, 8 patients (13.8%) as organic disease and 1 (1.7%) patient could not be classified. Fundus examination revealed abnormal findings in all patients classified as organic disease. Six patients had optic atrophy and 2 had abnormalities on the macula. Ten patients had an orbital magnetic resonance imaging (MRI) scan. Only 1 of 10 MRI scans showed causative abnormality, however, the patient showed an optic atrophy on fundus examination before the MRI scan.

Clinicians need to consider a high prevalence of functional visual loss and possibility of occult organic disorders when they evaluate pediatric patients presenting with decreased vision without distinct abnormities. MRI scan is recommended for only selected cases, when optic atrophy is not present.