Purpose: To evaluate retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness (GCLT), subfoveal choroidal thickness (SFCT), and central retinal thickness (CRT) in asthmatic children who were under inhaled corticosteroid treatment by using Swept-Source Optical Coherence Tomography (SS-OCT). Material and methods: Fifty-three children were prospectively analyzed in the study. Group 1 included 31 asthmatic children and group 2 included 22 healthy children. Asthmatic children received a dose 250 mu g daily of inhaled fluticasone propionate (Flexotide, GlaxoSmithKline, Middlesex, UK). Allergy parameters including, exposure to smoke, eosinophil count, percentage of eosinophils, immunoglobuline (Ig) E levels, number of asthma attacks, number of sensitivity to allergens and follow-up time were recorded. The RNFLT, GCLT, SFCT, and CRT were analyzed with SS-OCT and the data were compared between the groups. Results: There were 13 girls (41.9%) and 18 boys (58.1%) in group 1 and 13 girls (59.1%) and 9 boys (40.9%) in group 2 (p = 0.22). The mean age was 9.3 +/- 2.2 years in group 1 and 9.9 +/- 1.5 years in group 2 (p = 0.08). The mean CRT (239.26 +/- 34.56 mu m versus 226.82 +/- 26.23 mu m, p = 0.22) and mean SFCT (273.97 +/- 40.95 mu m versus 280.41 +/- 32.78 mu m, p = 0.54) did not significantly differ between the groups. The superior, inferior, and average RNFLT were significantly lower in group 1 than group 2 (p < 0.05). There were significant correlations between total corticosteroid dose and RNFLT (p < 0.05) and between IgE levels and GCLT (p < 0.05). Conclusions: The SS-OCT revealed that asthmatic children under inhaled corticosteroid treatment have lower RNFLT than healthy subjects.