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Comparison of associated heterophoria measurements using the Mallett test for near vision and the Sheedy Disparometer
Author(s) -
Pickwell L.D.,
Gilchrist J.M.,
Hesler J.
Publication year - 1988
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.1988.tb01077.x
Subject(s) - heterophoria , vergence (optics) , fixation (population genetics) , mathematics , optometry , psychology , orthodontics , artificial intelligence , strabismus , medicine , ophthalmology , computer science , population , environmental health
The Mallett test for near vision and the Sheedy Disparometer are compared in terms of their ability to measure associated heterophoria. Twenty‐two asymptopmatic subjects were used. With the Disparometer, ten of these subjects, familiar with making prism vergence measurements, exhibited stable forced vergence fixation disparity curves, and the associated heterophoria values using both instruments were not significantly different. However, the twelve subjects not familiar with making such measurements generated fluctuating, unstable fixation disparity curves, and the associated heterophoria values were significantly different. Repeated trials with the randomly selected naäve subjects led to flatter, more stable fixation disparity curves and lower values for the x‐and y‐intercepts when using the Disparometer. The Mallett test, however, produced identical values for associated heterophoria in each successive trial. Therefore, the validity of measurements using the Disparometer in a clinical setting is questioned.