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G. Rees, J.G. Ferraro, E. Lamoureux, J.E. Keeffe; Evaluation of Low Cost Low Vision Devices . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4403.
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© ARVO (1962-2015); The Authors (2016-present)
Although highly needed for daily functioning, low vision devices are often not affordable to people with low vision, especially in developing countries. Low cost low vision devices can be of great benefit, provided that they are of equivalent standard. The aim of this study was therefore to compare low cost magnifiers (LCM) with equivalent ‘gold standard’ (GSM) on reading performance and participants’ use and preference.
Participants were adults with visual acuity <6/12 in the better eye and proficient users of prescribed magnifiers. They were asked to read two passages of 173 words (grade 7 standard) with each device. Print size was matched to participants best corrected near visual acuity. All devices were unidentifiable and masked to both researchers and participants. The order of presentation of the devices was counterbalanced. Four powers of illuminated magnifiers were tested (10, 23, 28 and 50 diopters). All magnifiers were handheld with the exception of the 23 diopter stand magnifiers. Devices were closely matched to the participants’ prescribed magnifiers. Outcome measures were mean reading time (sec) and number of errors. Participants also rated the ease of use of each device on a four point scale (very easy to very difficult) and preference.
44 participants (29 females), with a mean age 75.6 yr (38–89), were recruited. The majority (82%) had age–related macular degeneration. Visual acuity ranged from 6/12 to <6/60. Overall, there was no significant difference in reading time (sec) for LCM (mean = 316.9, 95% CI 244.6 – 389.2), compared to GSM (mean= 321.4, 95% CI 245.6 – 397.1) (t=–0.6, df= 53, p=0.6). There was also no difference in reading errors between LCM (mean= 2.0, 95% CI 1.4 – 2.6) and GSM (mean= 1.9, 95% CI 1.4 – 2.5) (t=0.3, df=43, p=0.8). There were no significant differences in participants self rated ease of use (Wilcoxon z= –1.3, p=.19). Subgroups analysis revealed no significant differences on reading time, reading errors, or ease of use between any of the four LCM and the equivalent GSM (p>0.05). Seventeen participants (39%) preferred the low cost magnifier, 17 (39%) the high cost magnifier, and ten (22%) had no preference.
This study demonstrated almost an identical reading performance when using either low cost magnifiers or more expensive devices. This finding is critical especially for developing countries as the availability of low cost, high quality magnifiers can have huge implications for service provision and quality of life for people with vision impairment.
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