Yoked Prisms in the Carrier Lens (IMAGE) Mass Eye and Ear Caption By embedding the current prism in a spectacle lens that has prismatic power in the opposite direction, the image shifting effect is increased by the summation of the power of both prism types. This design allows for up to 36 degrees of expansion to the visual field on the patient's blind side. This design permits 5 degrees of scanning range to the blind side with full effect. Credit Massachusetts Eye and Ear Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.