Ophthalmic international standards, 1950.

ONE of the duties incumbent upon an international scientific organization is the establishment of a system of standard measures and methods for general use within its particular science. In ophthalmology, this need was beginning to be felt at the end of the 19th century, and at the X Ophthalmological Congress which was held at Lucerne in 1904 the Societe franQaise d'Ophtalmologie made certain proposals, which resulted in the election of a committee for the establishment of uniform determination and notation of visual acuity. The members of this commission were Charpentier, Dimmer, Eperon, Hess, Jessop, Nuel, and Reymond. Their report, presented to the XI Congress at Naples in 1909, recommended the use of standard tables with Landolt's broken rings, numbers with oblique straight lines (1, 4, 7), and numbers with curved lines (0), as optotypes, graduated on the decimal system and read at a distance of 5 m. A notation symmetrical between the two eyes was recommended for the meridians of astigmatism. These proposals were accepted by the Congress, but this attempt at standardization was not crowned with success, for the methods advised were never put into general practice and have now, for the most part, been abandoned. This failure was due to a number of different causes: many oculists preferred a reading distance of 6 instead of 5 m., some considered the decimal graduation to be less scientific and less practical than a geometrical progression, and some found the optotypes difficult to handle.