Hand held Maddox rod (groove)

Historical Significance: Maddox devised this test to dissociate the eyes for the measurement of heterophoria in 1890. In its original form it was a clear glass cylinder glass cylinder placed in front of one eye to distort a point light source into a line so that the line cannot be fused with the point source of light. It was later developed to have a larger aperture with multiple grooves (cylinders) known also as the Maddox rod or sometimes as the Maddox groove, although this later development was due to Aiken in 1894.The test was originally administered with a red filter in one eye to enhance the dissociation but modern Maddox rods (grooves) are made with red glass. This is a hand held test but they are also common in a form suitable for use in a trial frame and Maddox rods were later incorporated in refractor heads. See books by Maddox Cat No 107, 206, 207, 504. Maddox was an English ophthalmologist (1863 - 1933) who importantly elucidated the nature of binocular fusion and the components of convergence. He invented the Maddox rod and the Maddox wing test, the cheiroscope and the V test for astigmatism. He was ophthalmic surgeon at the Royal Victoria Hospital, Bournemouth, and formerly Assistant Ophthalmic Surgeon in the Royal Infirmary Edinburgh and Syme Surgical Fellow at Edinburgh University. See Cat No 554, 952 for examples of the original Maddox rod.