What am I? Medical Technology Exhibit HomeIron LungElectric Steam VaporizerViolet RayCystoscopeTrepan FrameSurgical Incision RetractorTool KitOphthalmoscope Hemodialysis De Zeng Ophthalmoscope ‹› Henry L. De Zeng Ophthalmoscope 1922 The Ophthalmoscope was patented by Henry L. De Zeng in 1922 and was used to check the interior of the eye for retinal ditatchment and other eye diseases.