• By means of postmortem dacryocystograms and photomicrographs of histological slides, the topography and morphology of the lacrimal passages in premature and mature newborn infants are demonstrated. Because of the bends in the course of the lower tear duct, a percentage of probings will fail to effect satisfactory perforation of Hasner's membrane. In most cases the soft texture of this membrane requires no more than syringing under pressure using a hollow probe.
Busse H, Müller KM, Kroll P. Radiological and Histological Findings of the Lacrimal Passages of Newborns. Arch Ophthalmol. 1980;98(3):528-532. doi:10.1001/archopht.1980.01020030524019