Ptosis is a not uncommon condition which often demands relief, not only for cosmetic reasons, but in many cases, to permit vision without extreme tilting of the head. The number of operations that have been proposed (fifty-five were described by Elschnig1) is evidence that none has given uniformly satisfactory results. A satisfactory description of the various types of operation employed is that of Lancaster.2 Such operations may be divided into three groups, according to the mechanisms involved. One group, of which the operation of Eversbusch is best known, attempts to shorten or advance the levator, usually with resection of a portion of the tarsus. Such operations are suitable only for partial ptosis, usually of slight degree, in which the levator is active. A second group, including the operation of Parinaud and its more generally accepted modification by Motais, unites part of the superior rectus with the upper lid.
GIFFORD SR. THE MACHEK OPERATION FOR PTOSIS. Arch Ophthalmol. 1932;8(4):495–502. doi:10.1001/archopht.1932.00820170015002