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Tasanee Braithwaite, Sheila Rae, Daryl Tabrett, Shahina Pardhan, Rupert R. Bourne; An Exploratory Study To Compare The Reliability, Validity, And Acceptability Of Four Near Visual Acuity Charts. Invest. Ophthalmol. Vis. Sci. 2012;53(14):3603. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
There are an estimated 410 million people with uncorrected presbyopia globally, but the available data are limited by the lack of a standardized approach to near vision assessment. Reading tests estimate functional vision but are inappropriate for illiterate adults, who make up 16% of the global population. LogMAR near visual acuity(NVA) charts with literacy-independent optotypes are commercially available but have not previously been validated or compared.
Repeated measures of binocular NVA were made for each distance-corrected subject, in the uncorrected(u) and best-corrected(c) near states. Luminance, illuminance, chart contrast and test distance were controlled in an optical lab. Corrected distance visual acuity(cDVA) was measured on a 3m ETRDS chart. The lens power needed to read N5 at 0.40m was recorded. Four NVA charts with identical design but differing optotypes were compared(Goodlite, USA): ETDRS with Sloan letters; four orientation tumbling E; four orientation Landolt C; and four Lea symbols. Time to determine uNVA and acceptability were assessed for each chart. The MNRead test was administered.
13 presbyopic subjects were included. The mean age was 57.6(10.9) years, 8 were male, and the mean lens power was +1.95(0.50) DS. The mean cDVA was -0.18(0.10) logMAR. Table 1 shows the mean NVA and test times. Repeated measures ANOVA with a Greenhouse-Geisser correction identified significant differences between the charts in uNVA(F=13.45,p<0.0005), cNVA(F=13.42,p<0.0005) and test time(F=16.81,p<0.0005). Post-hoc tests explored pairwise differences with a Bonferroni correction. The cNVA was significantly lower than the cDVA for all charts(p<0.01). The uNVA was significantly lower on the C than the other charts(p<0.0005). Test time was significantly faster on the ETDRS chart(p<0.03). Pearson correlation coefficients (Table 1) revealed strong associations between uNVA and reading acuity(p<0.0005), critical print size (p<0.0005), and add lens power (p<0.01) for all charts.
The charts generated reliable, valid measures of NVA and were acceptable to a sample of literate, presbyopic subjects. Significant differences in the observed NVA between charts merit further investigation.
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