Objective: The study assessed optic nerve diameter (OND) and clinical biomarkers in patients with poorly controlled diabetes compared with healthy nondiabetic volunteers. Materials and Methods: There were 1320 adult participants recruited to the study. The cohort was divided into 600 Type 2 diabetic (DM II) patients and 720 apparently healthy, nondiabetic volunteers. The OND was measured using a high-resolution dedicated ultrasound device (Sonoace 5500; Medicol, Medison, Miami, FL, USA) with a 10-MHz linear array transducer. Subjects were examined in a supine position with their eyes closed. Three measurements of the OND were taken and the average recorded. Hemoglobin A1c concentration and lipid profiles were determined using Bio-Rad Diamat analyzer (Bio-Rad, Hercules, CA). Body mass index and age were matched for both cohorts for comparativeness. Results: The mean OND of the DM II patients was 3.10 ± 0.14 mm (range of 2.6–4.0 mm), which was significantly ( P < .05) lower than the control volunteers (4.22 ± 0.15 mm). The OND demonstrated a negative significant correlation with HA1c, duration of diabetes and low-density lipoprotein cholesterol level ( P < .05). Lipid profiles, blood urea, serum creatinine, and hemoglobin A1c showed statistical difference between diabetics and control subjects. Conclusion: Poorly controlled DM II patients may have significantly narrower OND than nondiabetic patients. This imaging biomarker has the potential to transform visual care for DM II patients.