Abstract
Purpose :
The MNREAD ACUITY CHARTS are continuous-text reading-acuity charts designed to measure the reading performance of normal and low-vision subjects. This test is used to estimate a subject’s: 1) Maximum Reading Speed; 2) Critical Print Size; 3) Reading Acuity and a newly defined measure 4) Reading Accessibility Index (Calabrese et al., ARVO 2015). Clinical applications of MNREAD can benefit from baseline measures for normally sighted subjects. Here we report MNREAD values from a large group of healthy subjects covering a wide age range.
Methods :
Data were analyzed for 645 participants aged 8 to 81 years from several studies conducted by different testers in our research program over a period of 20 years. 475 were tested in our lab, and 170 at the Minnesota State Fair. All participants had normal or corrected-to-normal vision (mean distance acuity -0.09 ± 0.09 logMAR). MNREAD tests were administered binocularly at 40 cm following the recommended standard procedure. All subjects were tested with the black-on-white version of the test. For each test performed, all four MNREAD parameters were estimated and modeled as a function of age.
Results :
For the Maximum Reading Speed (MRS) and the Reading Accessibility Index (ACC), data were best fit using a trilinear dependence on age: first increasing from 8 to 16 years (MRS from 140 to 200 wpm; ACC from 0.7 to 1.01); then stabilizing in the range 16-35 years (mean MRS 200 ± 25 wpm; mean ACC 1.01 ± 0.14); and decreasing to 178 wpm and 0.86 by 81 years. The Critical Print Size was constant from 8 to 40 years (mean 0.08 ± 0.13 logMAR) and increased progressively after 40 up to 0.32 logMAR by 81. LogMAR acuity decreased from -0.1 at age 8 to -0.18 at age 16, and then progressively increased to -0.05 at age 81 (0.006 logMAR per year). There was no significant effect on any of the four MNREAD parameters of the testing location (lab vs. State Fair) or of the study tester.
Conclusions :
There is a modest age dependence of the MNREAD parameters for normally sighted subjects, which may be relevant to the interpretation of clinical results. In broad terms, MNREAD performance exhibits differences between three age groups: Children 8-17, Young Adults 18-39, and Older Adults >40. When uniform testing methods are used, the effects are stable across testing locations and testers.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.