Background: To analyze changes over a 3-year period in ganglion cell complex (GCC) thickness in individuals with type 1 diabetes mellitus (T1DM) using spectral-domain optical coherence tomography (Optovue, Fremont, CA, USA)., Methods: Thirty-seven individuals from "Friends for Life Conference" with T1DM and a 3-year history of GCC thickness measurements were included in the study. Data analysis using SPSS 22 and Excel StatPlus was completed to note the subgroups that had a significant change., Results: Significant decreases were noted in the following subgroups with slope in parenthesis. Overall: GCC superior thickness OD (-0.48)Male: GCC thickness OD (-0.86), GCC superior thickness OD (-0.735)Body mass index (BMI) 25.0-29.9: GCC thickness OD (-0.48), GCC superior thickness OS (-0.915), GCC inferior thickness OD (-0.43)Ages 10-20 years: GCC superior thickness OD (-0.635)Duration of diabetes 10-20 years: GCC thickness OD (-1.055), GCC superior thickness OD (-0.99)., Conclusion: GCC loss was noted in individuals who were males, those with BMIs of 25.0-29.9, and those who had diabetes for 10-20 years. Ganglion cell loss was also noted before the presence of any diabetic retinopathy, suggesting onset of neuronal loss before any vasculature changes., Competing Interests: There are no conflicts of interest.