A lens (10) and a method for forming the lens (10). The lens (10) including a base (12) with plurality of nano-particles (14) therein. The base (12) is made of glass. The nano-particles (14) can filter infrared rays from incoming light and are evenly distribute throughout the base. The method for forming a lens includes: (1) preparing a glass pre-form (60) with nano-particles (14) for filtrating infrared rays; (2) pressing the glass pre-form (60) using a press mold machine (500) to mold a lens (10).