FIGURE 4.

(A) Commercially available rigid PMMA oblique peripheral prism of 57Δ embedded in the left lens for a patient with left hemianopia. (B) Binocular visual field of a patient with left hemianopia wearing oblique prisms of 57Δ (30 degrees tilt angle) with a 12-mm interprism separation. Lateral 26 degrees field expansion and vertical 15 degrees shift were achieved with each segment; the gap between the prism expansion areas was eliminated. Note that the far peripheral field of this patient is smaller than a normal visual field (dashed line), yet the field expansion achieved by the oblique prism covers the view through the car windshield.