Common sense dictates the better these three factors are, the better the success with the aid will be. Success with any low vision aid however, does still depend on a degree of motivation and similar criteria for suggesting an optical magnifier should therefore still be used if recommending an EVES.Īs with traditional optical magnifiers, the prior assessment of visual acuity, contrast sensitivity and visual fields remains essential. ![]() Though this may obviously still hold some truth, encouragement of all age groups should now be the norm. Indeed, there has been rapid development in software used by existing electronic devices, such as tablets (figure 1) and smartphones, and these can offer often very cost-effective options using a medium everyone is familiar with and unlikely, therefore, to suffer some of the stigma associated with many low vision aids.įigure 1: Use of a tablet and a magnification appĮVES essentially present a magnified image upon a screen and may be complemented with further attempts at magnification, such as reduced working distance.Įxperienced low vision practitioners will be aware that the philosophy in the past was that electronic aids were only for the young and highly motivated visually impaired persons. Electronic devices nowadays are usually simple to use, often more so than a standard optical magnifier, and additionally have the advantage of being perceived as more socially acceptable. Manufacturers of electronic low vision aids have also moved with the times, from supplying a limited range of aids to a now fairly extensive selection.Ī patient’s success with a low vision aid does not just rest solely on acuity and other clinical measures, but is influenced by real life considerations such as ease of use and cosmesis. Patients attending low vision clinics are increasingly computer literate, some having had prior years of experience perhaps in their current or previous jobs or indeed at home. In the past, many low vision practitioners tended to shy away from recommendation of electronic low vision aids (which historically tended to be grouped together as CCTVs), or to use the preferred terminology ‘electronic visual enhancement systems’ (EVES), often, but not exclusively, due to cost factors or the patients unfamiliarity with electronic and computer-based devices.Ĭomputers and electronic devices are now well established in everyday life in schools, work environments and the home. This proof of concept study suggests that the principles underlying the gaze-controlled enhanced system might be further developed and fruitfully incorporated in different kinds of EVES for low vision reading.It has long been recognised that magnification can assist a visually impaired patient, or indeed any patient, in undertaking a variety of tasks, and therefore offer the chance to improve their quality of life and perhaps maintain independence. In addition, learning curves were similar in the three conditions. Importantly, reading speed results did not show any significant difference between the three systems. All subjects were able to use condition 1 and they found it slightly more comfortable to use than condition 2 (and similar to condition 3). Reading speed was measured and constituted the main dependent variable to compare the three conditions. Ten healthy subjects with a gaze-contingent scotoma read aloud sentences from a French newspaper in nine experimental one-hour sessions. A gaze-contingent artificial 10° scotoma (a mask continuously displayed in real time on the screen at the gaze location) was used in the three conditions in order to simulate macular degeneration. The three conditions were implemented on the same computer to remove differences that might have been induced by dissimilar equipment. In these two conditions, magnification was uniformly applied to the whole text without any possibility to specifically select a region of interest. Two other conditions were implemented that mimicked commercially available advanced systems known as CCTV (closed-circuit television systems)-conditions 2 and 3. We have developed and implemented a real-time gaze-controlled system whose goal is to optimize the possibility of magnifying a portion of text while maintaining global viewing of the other portions of the text (condition 1). Due to the restricted field of view of EVES, the need for magnification is conflicting with the need to navigate through text (panning). The flexibility of Electronic Vision Enhancement Systems (EVES) offers several ways of magnifying text. ![]() People with low vision, especially those with Central Field Loss (CFL), need magnification to read.
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