This prospective randomized controlled trial compares the effects of Minimally Invasive Extracorporeal Circulation (MiECC) versus conventional cardiopulmonary bypass (CPB) on optic nerve sheath diameter (ONSD) and postoperative stroke incidence in adult patients undergoing isolated open heart surgery. ONSD will be measured by ultrasound at 7 predefined time points (T0-T6). Primary outcomes include perioperative ONSD changes and 30-day stroke incidence. Secondary outcomes include TIA, delirium (CAM-ICU), MoCA scores, ICU and hospital stay, AKI, and transfusion requirements.