An improved device and method for safer and more efficient laser vein treatments are presented. The device includes an optical waveguide optically coupled to a radiation source at its proximal end, having a core, a cladding layer and a tip configured to protect the clad-core, e.g., from contact with collapsing vein walls during laser vein treatment, and to enhance treatment efficiency through improved centering. According to one embodiment, the clad-core is recessed within one or more jacket layers. In some embodiments, the protective jacket on the clad-core may be left on when the jacket layer is added. In embodiments, one or more protective wires are attached to the clad-core or a jacket layer and extend distally past the clad-core. In some such embodiments, three protective wires are substantially equally spaced relative to each other about the circumference of the core, i.e., forming an equilateral triangular pattern. The optical waveguide is useable in conjunction with an introducer structure having protective means to prevent damage to the vein walls, e.g., perforating the vein walls, during insertion of the optical waveguide into the vein. A method of using the device is also disclosed wherein a distal end of the optical waveguide is advanced to a desired position and essentially centered in the vein, and a predetermined wavelength of radiation is output from the distal end of the optical fiber while the optical waveguide is simultaneously withdrawn from the vein.