DAHLFELD'S experiments show that it is possible to discover the presence of foreign bodies in the eye by means of the X-rays; but that a negative result does not prove the absence of a foreign body, for this may lie in such a position as to be masked by the shadow of the orbital margin, and may be revealed only by placing the apparatus in a different position.
Reference:Arch Ophthalmol. 1898;27:140.
A look at the past . . .. Arch Ophthalmol. 1999;117(4):537. doi:10.1001/archopht.117.4.537