Figure 16. .

Unilateral oblique 57Δ peripheral prisms, ±30° apex-base angle at 12 mm interprism separation, provide access to pericentral regions. (A) Simulated Goldmann visual field diagram shows true expansion with no remaining apical scotomas. The dashed rectangle outlines the typical view area through a car's windshield.⁴¹ When driving, the prisms' expansion regions fall outside the direct road view, lessening any effect of visual confusion against the bland interior background. (B) The percept diagram shows the areas of visual confusion associated with unilateral fitting. (C) The magnified view of the upper prism area of (B) color-codes the monocular portions and shades the diplopic correspondence as in Figure 11. A portion of the small region of interocular diplopia is also seen as monocular diplopia by OS; inconsequential, but an interesting wrinkle. (Monocular diplopia occurs when the visual angle of the effective prism base-apex distance is less than the prism power.) When gaze is directed to the left (Supplementary Figs. S3A, S3B) the diplopic region increases. Although partially seen foveally, patients have not reported noticing it. (D) A measured patient visual field diagram.