and the life sciences as a whole, highlighting the key challenges and opportunities that the field faces and making some recommendations to government, academia, and the private sector.

Optics has enabled laser surgery, optical diagnostic techniques, and visualization of the body's interior (see Figures 2.1 and 2.2 and Boxes 2.1 and 2.2).

Although the applications of optics to surgery and medicine have increased rapidly since the invention of the laser in 1960, a number of optical techniques were used before that time. The development of rigid and flexible endoscopes—devices that allow the inside of canals (e.g., blood vessels) and hollow organs (e.g., the colon) to be viewed—is discussed in some detail elsewhere (Katzir, 1993). A number of rigid endoscopes were used in the nineteenth century, and the first flexible medical endoscope using optical fibers was demonstrated in 1959.

It is worth noting that the use of microscopes by pathologists to examine tissue in order to diagnose disease was a well-established medical application of optics long before the era of the laser. The microscope is still the essential tool of the modern pathologist, although it has been made optically more advanced by the advent of computer-designed lenses and high-quality antireflective coatings. Some clinical specialties use specially modified microscopes. Ophthalmologists use a modified microscope, called a slit lamp, to project a slit-like beam of light into the eye to detect scattering objects within the cornea and lens. Advances in microscopy continue and include efforts to automate microscopy to allow initial screening for disease and infection.

Arguably the most extensive use of optics in health care is in the fabrication of eyeglass frames, lenses, and contact lenses. This market was estimated at $13.2 billion in 1994 and consists of the 145 million people—55% of the total population—who wear corrective lenses (American Optometric Association, 1996). The ophthalmic market has evolved, with a variety of safe and light plastic lenses

FIGURE 2.1 A flexible gastroscope, used to examine the inner surface of the stomach, together with a view of the distal (insertion) end showing working channels for tools. The image of part of a dollar bill, taken using a flexible colonoscope with a charge-coupled device (CCD) camera at the distal end, illustrates the excellent resolution available. (Courtesy of Olympus America, Inc., and N. Nishioka, Massachusetts General Hospital.)