Prisms: Their Use and Equivalents

33 centimeters adduction ametropia ametropic correction amount appears displaced astigmatism axis 45 base down axis base in axis base-apex line centrad or prism-diopter centrad prism base centrads of exophoria cobalt blue glass Colored convergence convex crown glass cyclophoria cycloplegia cycloplegic Cyclotropia decentered 10 millimeters deviate a ray diopters diplopia downward axis 90 Edge or Apex equivalent exophoria geometric center heterophoria heterotropia horizontal Hyperexophoria hyperopia Illustrations incident ray index of refraction instance insufficiency lateral deviation left eye left hyperphoria lens lenses Maddox Double Prism Maddox rod meridian metamorphopsia meter angle muscle muscular numbering prisms object oblique Ophthalmology optic and geometric optic center parallel patient perpendicular phoria phorometer presbyopes prescribed prism Fig prism To obtain prismatic effect produce radian ray of light refracted ray right eye right hyperphoria rotation ruby red glass scale square prism squint straight line streak strength strong prism superimposed surface trial-frame vertical visual axis