Optometry originated with magnifying eyeglasses to correct for farsightedness in the 1200s A.D. but it was largely a trial and error practice. Then in 1450 Nicholas Krebs invented distance spectacles for nearsightedness. Eye surgery tools are more delicate than general surgery instruments and many, like the cyst and ulcer scoop, corneal splitting wedge, and some scissors, needles, probes and scalpels are specialized. Sets of eye surgical instruments were arranged in fitted wooden boxes. Eye testing kits or trial cases can include over 100 bi-convex and bi-concave lenses and accessories arranged in a fitted box. The ophthalmoscope, invented in 1850 by Hermann von Helmholtz, is a clever diagnostic instrument that reflects indirect light into the eye so a physician can view the retina. Around 1915 ophthalmoscopes were fitted with dry cell batteries. The ophthalmotonometer, which measures the inter-ocular pressure in the eye was invented in 1862, but only came into general use after 1905. The retinoscope, introduced in 1873, is simply a beam of light passed over the patient’s pupil from which the examiner estimates refraction error from the retinal reflection. The variator, an advanced type of retinoscope invented in 1932 uses adjustable telescopes that act as correcting lenses to measure refraction error.