Differences of retinal nerve fiber layer and ganglion cell layer-inner plexiform layer thickness in patients without diabetes mellitus. with diabetes mellitus type 2 without diabetic retinopathy and with diabetic retinopathy

Background: Prevention of Diabetic Retinopathy (DR) require an examination method that can identify earliest damage before clinical symptoms observed. This study aimed to determine the novel and objective way to detect those damage through retinal nerve fiber layer (RNFL) and ganglion cell layer–inner plexiform layer (GCL-IPL) thickness. Methods: This analytical cross sectional study research conducted at the eye polyclinic and the Diabetic Center of IGNG Ngoerah Hospital. Denpasar. This study comparing the difference in thickness of RNFL and GCL-IPL in patients without DM. with Type 2 DM without DR and with DR in average and each quadrant thickness through Kruskal Wallis and One Way Anova test. Result: A total of 59 participants were included in the study and divided into three groups: 20 individuals without diabetes mellitus (DM), 19 with DM but without diabetic retinopathy (DR), and 20 with DR. The average age of the subjects was 58.80 ± 9.65 years. RNFL measurements revealed significant differences among the groups in all quadrants except for the temporal quadrant (p = 0.518). However, after adjusting for age, HbA1c, blood pressure, visual acuity, intraocular pressure (IOP), and axial length, only the nasal and inferior quadrants remained significantly different. In the GCL-IPL analysis, significant intergroup differences were noted particularly in the superotemporal, temporal, and inferotemporal quadrants (p < 0.005), and these differences persisted after controlling for covariates. Conclusion: This study proved a neurodegeneration process that occured focally in certain areas that can be detected through the RNFL and GCL-IPL measurement modalities. These examinations were expected to be useful in terms of screening both primary and secondary in patients with type 2 DM.