Endovenous laser ablation, also known as laser vein ablation or endovenous laser therapy (EVLT), is a minimally invasive procedure to treat varicose veins that are not working correctly due to leaky valves in the vein. Through a small incision, a catheter (a small thin tube) is placed into the vein using ultrasound guidance. A laser fiber is inserted through the catheter and into the vein. The laser fiber delivers thermal energy directly to the vein wall, causing it to collapse and ultimately disappear from view. This process seals the vein shut, redirecting blood flow to healthier veins nearby.