Visual acuity: the ability of the human eye to distinguish the shape and position of external two-dimensional objects. Also called visual acuity. Visual acuity formula: visual acuity = 1/minimum angle of view. For example, if angle of view = 1, visual acuity = 1, and if angle of view = 10, visual acuity is 0.1. Adjustment Adjustment range: The distance between the near and far points. Adjustment range: The difference between the refractive power at the near point and the refractive power at the far point, expressed as a diopter. Example 1: Orthoopic eye Magnitude of accommodation = 1/r-1/p=1/infinity-1/-0.1=0+10=10D Example 2: Nearsighted eye Nearsighted eye with the far point at 50 cm and the near point at 10 cm in front of the eye Magnitude of accommodation = 1/r-1/p=1/-0.5-1/-0.1=-2-(-10)=8D