Yoked prisms and cerebral visual impairment: Enhancing the experience of ambient vision

Abstract

Background: Perceptual visual impairment leads to impaired functional vision in children with cerebral visual impairment. Yoked prisms have been used in behavioral vision therapy for children with autism (dysfunctional dorsal visual processing pathway) and in neurorehabilitation to treat visual neglect, hemianopia, and abnormal egocentric localization. In particular, they are employed for treating perceptual visual problems. Purpose: To share our experience in implementing yoked prisms and their impact on the rehabilitation of children with cerebral visual impairment-related perceptual vision disorders. Synopsis: The first child with periventricular leukomalacia exhibits no eagerness to explore her new environment along with poor grasp. With 4-PD base-down prisms, she explores her surroundings and appreciates her lateral supports. Her grasp improved as well. The second child with cerebral visual impairment exhibits difficulty in climbing downstairs with poor obstacle negotiation. This could be due to impaired inferior field awareness or optic ataxia. With 4-PD base-down prisms, the field shift toward the apex helps him to climb downstairs without difficulty with an improved obstacle negotiation. The third child prefers a closer look at the object of interest along with poor hand–eye coordination. We employed 4-PD base-down prisms in her rehabilitation session. She showed good improvement in her hand–eye coordination. Highlights: Poor hand–eye coordination, difficulty climbing downstairs, optic ataxia, impaired field awareness, and triggering spontaneous exploration in children with perceptual visual problems can be effectively tackled by the simple incorporation of yoked prisms. Video link: https://youtu.be/BW3cwiGDTLY

Keywords

• cerebral visual impairment
• perceptual vision
• yoked prisms