The Maddox Phoria Measure offers a quick and cost effective way of measuring phoria imbalances. It is a combination of a Moddox multiple rod coincident with a rotational prism. The test is the same in principle as the conventional trial frame mounted Maddox Rod and prism test. With the Phoria Meaure the Maddox Rods are fixed at the horizontal axis and the co-axial prism is mounted on a wheel to allow its orientation (angle) to be varied.

A special feature of the Phoria Measure is that it can be used horizontally and vertically with either eye to detect the presence of any heterophoria, whether EXO, ESO, R or L eye. This is indicated at the point when the streak formed by the Maddox Rods is seen passing through the light spot viewed by the other eye. The amount of prism required to reach this balance point is shown by the position of the notch on the rim of the prism wheel relative to the scale. The orientation of the device when used vertically or horizontally is clearly indicated by the printed arrows on the handle.

This device is neat, lightweight and made using high quality materials.