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. Author manuscript; available in PMC: 2018 Aug 1.
Published in final edited form as: Optom Vis Sci. 2017 Aug;94(8):817–829. doi: 10.1097/OPX.0000000000001102

Figure 8.

Figure 8

Field of view expansion of a monocular (right eye) patient with peripheral field loss and poor visual acuity (20/500). (A) PC-based perimetry without the prism. The red dotted outline represents the presumed prism position. The actual prism position varies with head posture. (B) Field of view with an EPS Press-On prism (40Δ). The field is shifted as well as the accompanying apical scotoma. Due to the upper prism position that covers the upper boundary of the visual field, the apical scotoma is connected all the way to the upper boundary of the visual field. (C) With an MxP in EPS, the apical scotoma is eliminated and there is true field expansion, not a just substitution. Black dashed line on each plot represents the boundary of the seeing field without prisms.