The MNREAD acuity chart or Minnesota low vision reading chart is a text based chart used to measure near visual acuity in people with normal or low vision.[1] It can also be used to measure maximum reading speed, critical print size and the reading accessibility index of a person.[2] Digital and printed types of charts are available.[3]
The MNREAD chart consists of sentences with print size decreasing by 0.1 log unit steps, from 1.3 logMAR (Snellen equivalent 20/400 at 40 cm) to −0.5 logMAR (Snellen equivalent 20/6).[4] Charts are available in many languages. It allows near visual acuity recording in logMAR notation, Snellen notation or M-units.[5]
Procedure
Since the MNREAD charts use logarithmic pattern of letters, near visual acuity is usually measured at a distance of 40 cm from eyes. For low vision patients, chart can also be used at closer distances.[1] After distance vision correction, near vision is measured with and without near vision correction.
History
Gordon Legge and colleagues introduced the computer based Minnesota low-vision reading test in the year 1989.[6] In 1993, they introduced a simplified printed version of the test. The chart we use now is developed at the Minnesota Laboratory for Low-Vision Research, University of Minnesota, by Gordon Legge, Steve Mansfield, Andrew Luebker, and Kathryn Cunningham.[7]