Obscured interdigitation zone at the early stage of gyrate atrophy: A case report

PURPOSE: To report an early stage of gyrate atrophy (GA) of the retina and choroid for which spectral-domain optical coherence tomography (SD-OCT) images revealed an obscured interdigitation zone (IZ). OBSERVATION: A 13-year-old boy was referred to our department due to blurred vision in his left eye. Best corrected visual acuity was 20/20 and 20/25 in the right and left eye, respectively. Fundus examination revealed scalloped atrophic peripheral chorioretinal lesions in both eyes. Concentrations of plasma and urine ornithine were 1192 nmol/mL and 1930 μmol/g·cre, respectively. Consequently, he was diagnosed with GA. Although Goldmann perimetry found no abnormalities, electroretinogram (ERG) revealed loss of the rod responses and significant attenuation of the cone responses in both eyes. Detailed analysis of the posterior part of the fundus using multifocal electroretinogram showed poor responses, specifically in the nasal macular area of the left eye. SD-OCT showed an obscured IZ corresponding to the attenuated cone response determined by ERG. There was preservation of the retinal pigment epithelium, ellipsoid zone and external limiting membrane. CONCLUSIONS AND IMPORTANCE: Obscured IZ during early stage GA was confirmed in a teenage patient with a chief complaint of blurred vision. OCT is useful in the detection of minute morphological changes that occur earlier in GA.