The sensory mode “ease of seeing” was scaled by the technique of direct magnitude estimation. The derived scale is a power function of visual acuity measured with equity measured with equivalent stimulus values. These findings suggest that if visual acuity measurements are to be representative of the sensation “ease of seeing,” then the character sizes on visual test charts must be graded in a geometric progression of visual angle. A scale of visual utility is proposed in which it is possible to express changes in basic visual acuity measurements (e.g. Snellen fraction), in terms of multiples or fractions of unitary changes in visibility.