Difficulty reading is the most common complaint of low vision patients. It is the Activity of Daily Living that is most closely related to visual acuity, but involves many additional factors beyond.
Print SIZE provides an assessment (visual acuity) of "How the EYE functions".
Reading SPEED provides a convenient assessment of “How the PERSON functions.”
PDF Reading acuity (2005)
The IVA system (see below) contains a module to facilitate reading speed measurements.