A multiple-scales concept for describing visual acuity

In this paper a model of the essential stages of the early-visual system for normal-sighted persons is proposed. The model is based on summation of neural activity within and over a number of size-varying channels and is capable of predicting the influence of contrast reduction and blur on visual acuity, which is thought to be the most important visual variable determining reading performance and rate. The model gives a meaningful description of the early-visual mechanisms involved in detail perception and can be used to derive guidelines for text enhancement for subjects with low vision.