A rare and technically sophisticated antique Hare ophthalmoscope dating to around 1915, representing one of the more ingeniously designed electric ophthalmoscopes of the early 20th century. The Hare ophthalmoscope was produced in two versions: one using the older style of reflected light from a mirror, and one battery-lit. This example is of the latter type, with one important distinction — rather than an internal battery, it is powered via an external cord that would have been connected to a transformer, placing it at an interesting transitional point in the electrification of clinical ophthalmic instruments.
The instrument features an unusually designed lens disc with geared overlapping dials that provide a continuous change of lens power from -1 to -29 diopters and +1 to +20 diopters in 10 steps — a notably wide and finely graduated range for its era. An additional +20 diopter lens is mounted on the reverse side of the instrument, accessible via a lever on either side of the column. The mirror is slotted from the base to the focus of illumination, and the focus itself can be adjusted by sliding a knurled ring on the column either up or down, allowing precise control over the quality and depth of the illuminating beam.
The back side of the scope bears the logo of Genothalmic (General Optical Co. Inc.) — the American optical instrument company responsible for distributing this fine instrument.
A well-engineered and historically interesting example of early electric ophthalmoscope design, with a notably advanced lens system for its period.
