Lasers are an integral part of today's health care delivery system. They are used in the laboratory analysis of human blood samples; serve as surgical tools that kill, burn, or cut tissue; and are used in ophthalmology to weld torn retinas. Semiconductor microtechnology has reduced the diameter of a laser to a fraction of a human hair to create micro-electro-mechanical systems (MEMS). MEMS devices are expected to advance health care delivery.