Extremely rare. An instrument of the most profound historical significance in the entire history of medicine — an antique Helmholtz Ophthalmoscope, one of the rarest and most coveted objects in all of ophthalmic collecting.
In 1851, Hermann von Helmholtz published his landmark article describing his ophthalmoscope — an invention that for the first time in history allowed a physician to look inside the living human eye and observe the retina, optic disc, and blood vessels directly. It is difficult to overstate the magnitude of this achievement: the ophthalmoscope transformed ophthalmology from a discipline largely limited to the external eye into a window onto the entire nervous system, and its invention is widely regarded as one of the most important moments in the history of medicine.
This instrument was constructed by Rekoss, instrument maker to the University of Königsberg, under Helmholtz’s direction. It consists of a lens holder with a viewing hole of 3mm diameter, a frame containing three glass plates stacked on top of each other, and seven negative correcting lenses. The glass plates are attached at the polarization angle of 56 degrees to the instrument, forming a semi-transparent mirror. The examiner directs light from a source onto the glass plates at 56 degrees, which reflects the light bundle into the subject’s eye, directly opposite. The examiner can then look through the sight hole with the beam of light into the subject’s eye — the founding principle of all ophthalmoscopy that followed.
Presented in its original fitted wooden case, this is without question a museum-quality treasure of the first order.
The above photo was kindly allowed to be taken by Gary Edwards, M.D., by the curator of the Berliner Medizinhistorisches Museum der Charité in May 2010. The museum’s specimen is one of only a handful remaining in the world.
