Pickwell L D, Kaye N A, Jenkins T C
Department of Optometry, University of Bradford, West Yorkshire, UK.
Ophthalmic Physiol Opt. 1991 Oct;11(4):291-6.
Distance and near readings of associated heterophoria were taken, using standard Mallett units, on 500 patients passing consecutively through an optometric practice and any symptoms, connected with distance and near vision, were noted. Complete sets of results were obtained on 383 people. Distance readings, either in size or direction, did not appear related to symptoms and such readings did not appear helpful in patient management. For near vision a fair degree of association existed between readings of associated phoria and symptoms and it was possible in the under 40 years and 40-59 years age groups to express clinically useful rules regarding the relationship. Over 60 years of age such a relationship was complicated by the fact that high degrees of exophoria readings existed in both symptomatic and asymptomatic patients and it is suggested that this may be related to the quality of binocular vision.