Diamond knife

A diamond knife is a very sharp knife in which the edge is made from diamond, invented by Humberto Fernández Morán in 1955. Diamond knives are used for medical and scientific applications where an extremely sharp and long-lasting edge is essential. The knives are very expensive to initially purchase, depending on the quality and size of the knife; in addition the knives must be professionally sharpened as the edge dulls.

Eye surgery

Diamond knives are used in eye surgery, specifically in refractive surgery.

In particular they are the main tool, together with the microscope, for the radial keratotomy invented by Svyatoslav Fyodorov to correct myopia and for the Mini Asymmetric Radial Keratotomy (M.A.R.K.), invented by Marco Abbondanza to correct astigmatism and cure the first and second stages of keratoconus.

Ultramicrotomy

When the development of ultramicrotomy evolved, it was also determined that metal microtome knives or razor blades were too dull to cut ultrathin sections. The metal knives were soft and fragile and would lose their cutting edges when thin sections were required for transmission electron microscopy. In 1950, Latta and Hartmann discovered that the edge of broken glass could be used to cut thin sections of specimen.Glass knives are very popular in ultramicrotomy for trimming specimen blocks and cutting thin and ultrathin sections. A skilled operator can cut a small number of ultrathin sections with a glass knife, while the same operator can use a diamond knife to cut thousands of sections on one area of knife. Some hard specimens, such as bone, plants, thick-walled spores metals and ceramics are difficult to cut, even with a good glass knife, because the edge dulls too quickly.Humberto Fernández-Morán discovered that a gem-quality diamond could be used to fabricate a more durable knife for use in the ultramicrotomy; diamond was a logical material to use since it was the hardest known material at the time.