Artificial heart valve was later changed to use silicone-coated material. The first implantation of mechanical heart valve to human was performed by Dr. Hufnagel on 11 September 1952, using the valve that he developed. This event accelerated the development of other artificial heart valves. Artificial heart valve An artificial heart valve is a device implanted in the heart of a patient with valvular heart disease. When one of the four heart valves malfunctions, the medical choice may be to replace the natural valve with an artificial valve. This requires open-heart surgery. Valves are integral to the normal physiological functioning of the human heart.
Rayner (company) London, Ridley performed the first IOL operation on the eye of a 45-year-old female patient. The operation was conducted in secret, done in two stages with the artificial lens permanently implanted three months later. In 1952 the first IOL implant was performed in the United States: a Ridley-Rayner lens was implanted at the Wills Eye Hospital in Philadelphia. Surgeons Turgut Hamdi MD and Warren Reese MD implanted a series of these lenses – some with good visual function results (reported in a review by Dr Charles Letocha in the "Journal of Cataract and Refractive Surgery" in 1999). A lens designed