Evaluation of Metabolite Changes in the Occipital Cortex of Patients with Idiopathic Infantile Nystagmus or Bilateral Ametropic Amblyopia by Magnetic Resonance Spectroscopy

PURPOSE: To evaluate the effects of idiopathic infantile nystagmus (IN) and bilateral ametropic amblyopia on metabolites in the occipital cortex by magnetic resonance spectroscopy. METHODS: The children included in this prospective study were divided into three groups. Group 1 consisted of 11 patients with idiopathic IN, group 2 consisted of 10 patients with bilateral ametropic amblyopia and group 3 consisted of nine normal children. A single-voxel magnetic resonance spectroscopy examination was performed by placing a region of interest on the occipital cortex of each participant. N-acetyl aspartate (NAA), creatine (Cr) and choline (Cho) concentrations were measured in the occipital cortex. This was followed by calculating and comparing the NAA/Cr and Cho/Cr ratios between the three groups. The Kruskal-Wallis test, Mann-Whitney U-test, and chi-square test were used for statistical analysis. RESULTS: There was no statistically significant difference in NAA/Cr ratios between patients with idiopathic IN and normal children, but there was a statistically significant difference between these groups when Cho/Cr ratios were compared; the ratio was higher in the idiopathic IN group. There were no statistically significant differences in NAA/Cr or Cho/Cr ratios between patients with bilateral ametropic amblyopia and normal children. CONCLUSIONS: Our findings suggest that the neurochemical profile of the occipital cortex is partially affected by idiopathic IN, but not by bilateral ametropic amblyopia.