Tsutomu Sato (1902 – June 9, 1960) was a Japanese ophthalmologist who performed an early version of the radial keratotomy and was the first professor at the Research Institute of Ophthalmology at Juntendo University School of Medicine.

Biography

Sato was the first professor at the Research Institute of Ophthalmology at Juntendo University School of Medicine, where he researched the treatment of eye conditions such as

trachoma Trachoma is an infectious disease caused by bacterium '' Chlamydia trachomatis''. The infection causes a roughening of the inner surface of the eyelids. This roughening can lead to pain in the eyes, breakdown of the outer surface or cornea of ...

and myopia. In the mid-1930s, Sato devised a glass

scleral lens A scleral lens, also known as a scleral contact lens, is a large contact lens that rests on the sclera and creates a tear-filled vault over the cornea. Scleral lenses are designed to treat a variety of eye conditions, many of which do not respo ...

, but it never came into wide usage. Within a few years, higher-quality glass scleral lenses from

Carl Zeiss Carl Zeiss (; 11 September 1816 – 3 December 1888) was a German scientific instrument maker, optician and businessman. In 1846 he founded his workshop, which is still in business as Carl Zeiss AG. Zeiss gathered a group of gifted practica ...

were available in Japan. In 1939, Sato became the first physician to report the use of radial keratotomy for myopia. Sato knew that the cornea flattened out in patients with keratoconus who suffered

corneal hydrops Corneal hydrops is an uncommon complication seen in people with advanced keratoconus or other corneal ectatic disorders, and is characterized by stromal edema due to leakage of aqueous humor through a tear in Descemet's membrane. Although a hydro ...

from the leakage of fluid through

Descemet's membrane Descemet's membrane ( or the Descemet membrane) is the basement membrane that lies between the corneal proper substance, also called stroma, and the endothelial layer of the cornea. It is composed of different kinds of collagen (Type IV and VIII) ...

. His idea was to create numerous breaks in that membrane through anterior and posterior approaches. His initial patients were military pilots. Sato stopped performing his procedure because of the increasing availability of contact lenses in the late 1950s. In the years after Sato's version of the procedure was stopped, many patients experienced corneal decompensation and bullous keratopathy. When the Sato procedure was developed, there was no awareness of the importance of a layer of eye cells known as the

corneal endothelium The corneal endothelium is a single layer of endothelial cells on the inner surface of the cornea. It faces the chamber formed between the cornea and the iris. The corneal endothelium are specialized, flattened, mitochondria-rich cells that li ...

. By making incisions into both the front and back of the eye during the Sato procedure, surgeons were unknowingly disrupting the corneal endothelium, which would lead to corneal complications years later. When

Svyatoslav Fyodorov Svyatoslav Nikolayevich Fyodorov (; August 8, 1927 – June 2, 2000) was a Russian ophthalmologist, politician, professor, full member of the Russian Academy of Sciences and Russian Academy of Medical Sciences. He is considered to be a pioneer o ...

took up the procedure in the Soviet Union, he avoided these complications by making his incisions only from the front side of the eye. In 2003, the experiences of Japanese citizens with the Sato procedure were cited as still being a factor in the country's low rate of refractive surgery. About 48,000 refractive procedures were carried out that year in Japan, compared to 1.4 million procedures in the United States over the same period.

References

{{Authority control 1902 births 1960 deaths Japanese ophthalmologists