Large Aperture Maddox Phoria Measure

Large Aperture Maddox Phoria Measure

  • $102.95
    Unit price per 
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Key Features

  • Viewing Area of 190% larger (48 mm prism vs 25 mm)
  • Calibrated with Ohio State Diopter Rule
  • Disassembles for easy cleaning
  • Supports both Horizontal and Vertical Phoria measure

This Large Aperture Maddox Phoria Measure offers a quick method for the measurement of phoria imbalances. Compared to Maddox Phoria Measures previously available, this new product from Good-Lite employs a 48 mm prism rather than the traditional 25 mm prism in order to make it easier to use with children, Low Vision patients, and others who may be visually impaired.

Basic Description:

Maddox Phoria Measures are designed to measure Anisophoria which is the change in the phoria away from the primary position. They can be used vertically or horizontally with either eye. The new Good-Lite version combines a large 48mm aperture, a red Maddox mounted perpendicular to the handle in a prism in an indexed (notch) rotating disc with knurled edge. The label on the periphery of the prism mount indicates the effective prism power from 0D (diopter) to 10D. Maddox filter is not removable.

When the handle is vertical, Maddox Rods are horizontal and the patient sees a vertical streak. When the handle is horizontal, Maddox Rods are vertical and the patient sees a horizontal streak.


Because the Maddox filter prevents binocular fusion of the retinal image, Maddox Phoria Measure devices enable comparison of the natural resting position of the eyes (heterophoria, whether EXO, ESO, R, or L eye). As a result, Common Symptoms include headache, motion sickness, vertical or horizontal diplopia, asthenopia (eye strain), sleepiness when reading, and poor reading speed. Measurement of the degree of exophoria or esophoria assists the eye care professional in treating the condition with the degree of prism correction, vision training, or surgery of the eye muscles needed to overcome the phoria.


Our improved Large Aperture Maddox Phoria Measure employs simple plastic binding posts on the handle. These can be easily disassembled to permit cleaning of all of the ‘layers’ of the device.

Click here for the 658900 Guide.

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