The Use of Vertical Yoked Prisms in College of Optometrists in Vision Development Members

Abstract

Background: Vertical yoked prisms for treatment for binocular, accommodative, refractive, gait, posture, and behavioral conditions has been recommended by various authors. Few clinical trials have assessed the safety and efficacy of this practice. The purpose of this study is to estimate the frequency of vertical yoked prism use in vision therapy and spectacle prescriptions in a sample of College of Optometrists in Vision Development (COVD) membership. Methods: Multiple invitations to participate in a prospective anonymous survey were sent to all COVD members by email in October 2019. Results: One hundred twenty-three COVD members participated. Eighty percent use vertical yoked prisms in vision therapy and 83% prescribe vertical yoked prisms in habitual spectacle prescriptions. Base down and base up across a range of powers are used about equally in therapy. Base down is prescribed more commonly for esophoria and myopia. Base up is prescribed more commonly for exophoria. Base down and base up are prescribed about equally for oculomotility, perceptual conditions, posture and behavioral conditions such as autism. Sixty three percent of respondents plan to wean patients off the prism prescriptions. Conclusions: Vertical yoked prisms are commonly used in vision therapy and prescribed in habitual spectacle prescriptions in this sample of COVD members. Given the high frequency reported, larger controlled studies on safety and efficacy are in order.