Two-year longitudinal study on changes in thickness of the retinal nerve fiber layer and ganglion cell layer in children with type 1 diabetes mellitus without visual impairment or diabetic retinopathy

Purpose To study changes in the thickness of the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) in children with type 1 diabetes mellitus (T1DM) without visual impairment or diabetic retinopathy (DR) after 2 years of follow-up and analyze the associated factors. Methods Thirty-seven children with T1DM were enrolled in this study. All children underwent a complete ophthalmologic evaluation that included swept-source optical coherence tomography at baseline and follow-up. Changes in RNFL and GCL thickness were compared among the children at baseline and follow-up. Results The peripapillary RNFL thickness was greater in the temporal (inner, p = 0.015; outer, p = 0.004) and inner superior (p = 0.043) sectors in the follow-up group than in the baseline group. The macular RNFL thickness in the fovea, inner nasal sector, inner inferior sector, and outer ring and the average thickness (all p < 0.05) were greater in the follow-up group than in the baseline group. The peripapillary GCL thickness decreased in the temporal sector (inner, p = 0.049; outer, p = 0.041) and increased in the inner nasal sector (p = 0.006) in the follow-up group compared with the baseline group, and the thickness of the inner temporal, inner superior, inner inferior, outer nasal, and outer inferior sectors and average thickness in the macula were lower in the follow-up group than in the baseline group (all p < 0.05). The total retinal thickness around optic disc in the follow-up group increased in the inner superior sectors (p = 0.006). The total retinal thickness of the macula decreased in inner temporal sector, inner superior sector and outer nasal sector, and increased in outer superior sector (all p < 0.05). Conclusions Retinal neurodegenerative changes preceded microvascular changes in children with T1DM in the early stage. Peripapillary RNFL thickness in the nasal sector may be lower in children with T1DM without visual impairment or other ocular pathologies.