Article Comparison of MKH-Haase Associated Phoria Charts with Other Common Clinical Tests

Background: The Pola Test measures associated phoria at distance and near using a variety of different targets. This testing method and interpretation is referred to as the MKH-Haase method. The aim of this study is to compare the associated phoria values measured using the MKH-Haase chart results with other associated phoria tests. Methods: Horizontal and vertical associated phorias were measured at distance and near for 30 symptomatic and 30 asymptomatic participants. The tests used in this study were the Cross, Pointer, Double Pointer, and Rectangle Tests of MKH-Haase charts at distance and near. The other tests were the Mallett Test and AO Slide at distance and the Mallett Unit, AO Card, Saladin Card, Wesson Card, and Sheedy Disparometer at near. Results: Horizontal associated phoria tests without central fusion lock were significantly different from those with central fusion lock at distance and near. The mean Disparometer associated phoria was more esophoric than all of the other tests. Although there was a significant difference between various horizontal associated phoria tests at distance and near, most of the mean values differed by only 0.50 for the asymptomatic group. The differences between tests were larger for the symptomatic group. The largest difference occurred between the Disparometer and the Wesson Card, where the mean values differed by 2.00. Vertical associated phoria tests did not show any significant differences. The limits of agreement between the horizontal associated phoria tests that were not significantly different were usually within ±1.00 for the asymptomatic group. The limits of agreement between tests for the symptomatic group could be as large as ±2.50. Conclusions: The larger differences found between tests for the symptomatic subjects suggest that prescribing prism based on just one associated phoria test may not be the best practice.