|Programm||"Degeneration und Regeneration– Grundlagen, Diagnostik und Therapie"|
From Christoph Scheiner to the Modern Ophthalmometer
We are giving a historical survey of developing of keratometry and ophthalmometry. Already in 1619 Ch. Scheiner measured the curvature of the anterior surface of the cornea with a series of graduated marbles.The idea of his experiment that he held a needle before a card, pierced with two holes was later integrated in researching by others inventors. He is the ancestor of ophthalmometry. The investigations by Scheiner were used in the following time by many oculists to research the refraction of the anterior corneal surface. Before the ophthalmometer by Helmholtz the first period we have to mention : the optometer by Ph. de la Hire (1685), W. Porterfield (1759) and Th. Young (1801). We are owning the name ophthalmometer by Abbé Bignot (1728) and independent of him by Helmholtz (1855).The doubling princip introduced by S. Savery (1753) in the heliometer, have been adopted by E. Home and J. Ramsden (1796) and later by H. v. Helmholtz (1855). G. H. Gerson (1810), R.Kohlrausch (1836) and K. E. Senff (1846) employed metal discs with semicircle arc. Kohlrausch, the grandfather of the ophthalmometry, determined the corneal radius at first. W. Whewell (1849) designated the unspherical corneal surface as astigmatism. With the second great invention the ophthalmometer v.Helmholtz became the father of the ophthalmometry. It was the begin of the second period of ophthalmometry. The difficult handling was the reason for different changes of this instrument, especially by E. A.