All the earliest ophthalmoscopes required an external light source to illuminate the pupil. The easiest way to direct the light was by using a mirror. Ophthalmoscopes with fixed mirrors required the physicians to physically move themselves to capture the light source they are using- be it a candle or a lantern. In 1882, George Lindsay of London solved that problem by inventing an ophthalmoscope with a rotating mirror. The mirror could be spun, often on two axis, to capture the light in the best way possible.