The Examination Of Young Children
Materials Required With Children
- Cover glasses or patch.
- Visual acuity chart suitable for children and adequate lighting.
- Pointer.
- Example chart.
- Pointing chart.
Cover Glasses Or Patch
A cover spoon is not a suitable cover method for young children. It is too easy to look past the spoon, without it being noticed by the examiner, and thereby to look with both eyes. The cover patch is more suitable. It can be more child-friendly by adding stickers of popular TV characters [Figure 21]. If necessary, two sunglasses can also be used. Glass is removed from the right and the left one is taped and decorated, and vice versa. If children want to ‘cheat’, it is more obvious because they turn their head in all sorts of directions to achieve this.
Figure 21
Suitable Visual Acuity Chart
Various visual acuity charts are available for the examination of vision in children [Figures 22, 23]. For children of pre-verbal age or severely mentally disabled children who are not capable of naming images, Teller acuity charts can be used.
From the age of 2 to 3 years, the Amsterdam Picture Chart-TOV or the LEA-symbols can be used, either grouped in the Hyvärinen chart or applied as individual symbols (less reliable). Most modern visual acuity charts for children are standardised for a distance of 3 m. Ensure that the chart is placed at child’s height. This chart needs to be illuminated with a light intensity of 100 lux.
Figure 22
Figure 23
Pointer
To clearly indicate the symbols on the chart, it is important to have a pointer available. As with the symbols, it is best for this to be black, to achieve a maximum contrast with the white background of the chart.
Example Chart
To familiarise the children with naming of symbols, the parents may be supplied with an example chart to practice at home [Figure 24]. This would make the examination more reliable.
Figure 24
Pointing Chart
Some shy or insecure children may find it difficult to name symbols when being placed in an unfamiliar surrounding. Often, they are able to point to the indicated symbol on an example chart that is held by their parent or guardian.
Procedure
The technique of the vision examination in children is no different from that in adults [Figure 25].
Figure 25
- Allow the child to stand at the distance indicated on the chart. They may stand up or sit down. Depending on this, the chart should be at the correct height. If the child does not want to sit on the chair alone, they are allowed to sit on their guardian’s lap. Ensure that the chair is moved backwards in order to allow the child to sit at the required distance.
- A problem in this cohort is that they often refuse to put on the cover glasses. A solution to this is to have various versions available. Decorate them with various images of TV characters or let the child choose which glasses they want [Figure 26].
Figure 26
- Young children are not capable of indicating when they do not see something clearly. Instead, the child displays this by losing concentration, fidgeting, or talking about other subjects. However, this may also happen because the child has a short attention span. To distinguish between the two, one needs to revisit the previous line on the visual acuity chart. If the child is able to easily name this line, you attempt the next line once more. If the outcome is the same again, it is a strong indication that the child does not see the symbols clearly, loses interest and stops cooperating. A child that simply has had enough will not name the previous line either.
- The level of vision is noted next to or above the line on the chart, as with visual acuity charts for adults.
It should be noted that it is very hard, if not impossible, to conduct the examination with a stenopeic opening in young children. There is reason to refer the child for further examination by the ophthalmologist and/or orthoptist if there is a difference of two lines between the vision of both eyes (the right eye can see down to the last line of the chart, whereas the left eye can only see down to the third-to-last line of the chart). An exception to this is the “old” version of the Amsterdam Picture Chart. When examining using this chart, no difference between both eyes is permitted (one eye that sees to the last line and one to the second-to-last means an indication for referral).