Focuses light in only one dimension. Similar to a plano-convex lens in profile, but is a portion of a cylinder instead of a sphere. Cylinder lens can transform a point of light into a line image. This is useful for making laser line generators. The lens magnifies in one dimension so it can be used for stretching images. Can be used for focusing light into a slit or converging light for a line scan detector. Due to a tighter tolerance on tilt and wedge, high performance imaging lenses will give straighter lines and better images than standard cylinder lenses.