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Low vision aids for young visually impaired children

Focus: Early intervention

Topic: Low Vision

Roelof Schellingerhout

Senior researcher

Social and Cultural Planning Agency

Parnassusplein 5

Den Haag

The Netherlands

+ 31 70-3417812

r.schellingerhout@scp.nl

Nienke Boonstra

Ophthalmologist

Bartimeus institute for the visually impaired

Utrechtseweg 84

Zeist

The Netherlands

+31 30-698211

n.boonstra@bartimeus.nl

1. Introduction

The use of low vision aids is not a common practice in the care for young visually impaired children in the Netherlands. Both from the literature and from the experiences of practitioners, there are reasons to believe that low vision aids, such as magnifying glasses, may be beneficial for young visually impaired children. The possible beneficial effects of the early use of low vision aids include an increase in independence, a more effective use of visual possibilities, and the construction of a visual data-base.

To investigate the use of low vision aids for young visually impaired children, the Bartimeus institute in the Netherlands has initiated a long-term project, which incorporates several related investigations. The first investigations have focussed on the development of precise methods to study and measure the use of low vision aids. These first researches, with pre-schoolers with normal vision, were necessary because there is no relevant literature on the subject. The next researches, which are currently being prepared, will focus on the visually impaired children themselves. The research with the visually impaired children will include a training period, in which a child learns to use a magnifying glass. The methods and measures developed in the earlier researches will be used to measure changes in a child’s behaviour, related to the use of the magnifying glass. If this training programme is met with success, the use of low vision aids for young visually impaired children will be implemented on a larger scale in the Netherlands.

2. Research

In the researches with sighted pre-schoolers, a task was used in which the child had to identify pictures with or without the use of a magnifying glass. The pictures the child had to identify in the research were scale-reduced versions of pictures used in standard tests to measure visual acuity. The scale of the pictures was chosen in such a way that it was either above or below the child’s near vision measured at 20 cm.

Two versions of the task were used:

  1. A version in which the behaviour of the child was unrestricted, i.e., the child could reduce the viewing distance to the picture at will (the child could bend forwards to bring its’ eyes close to the picture). The number of children tested with this version of the task was 15, ranging from 2,6 to 4 years of age.
  2. A version in which the behaviour of the child was restricted, i.e., the child could not reduce the viewing distance to the picture below a distance of 20 cm (the pictures were placed in a wired frame). The number of children tested with this version was 13, ranging form 3 to 4 years of age.

The aim of these first researches was:

  1. To investigate whether pre-schoolers were interested in and would be willing to use a magnifying glass
  2. To develop a coding scheme to measure the use of a magnifying glass by young children
  3. To investigate whether children would identify more (and smaller) pictures with the aid of a magnifying glass.

3. Results and conclusions

All of the children were interested in the magnifying glasses and had fun using them. This indicates that the motivation of the children will probably not be a problem in the training programme to learn to use a magnifying glass.

From the video-recordings of the children’s behaviour with the magnifying glasses, a preliminary coding scheme was developed, which will form the basis of the coding scheme to be used with the visually impaired children. Not surprisingly, the single most important behaviour related to the identification of the pictures seems to be the reduction of the viewing distance.

In both researches, the most important effect was the scale-size of the pictures. The children could identify more larger pictures than smaller pictures, regardless of whether they used a magnifying glass or not. The use of the magnifying glass had no effect on the number of pictures a child could identify in the first version of the task. In the second version of the task, there was a small effect of the use of a magnifying glass, but only for some children who, by chance, were tested under difficult circumstances (noisy environment).  A major confounding factor in the research however, was the visual acuity of the children. The visual acuity of part of the children was such that they could identify the smallest pictures used without the aid of a magnifying glass at a distance of 20 cm. Expectations are that effects of the magnifying glass on the identification of the pictures will be much greater with the visually impaired children.

An unexpected result was that some pictures were more easily identifiable than others. E.g., the picture of a circle was identified correctly more often than the picture of a fork.


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