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with the 20/20 line and then go to larger lines if the child is having trouble. The
child needs to recognize only a few letters on each line. Minor errors such as the
substitution of the letter F for the letter P, or the letter C for the letter O, may be
tolerated.
It is almost an instinct for young children to use their better eye and suppress
the vision in their lesser eye. The examiner should ensure that it is not possible to
peek with the nontested covered eye. Therefore, children should not be allowed to
cover their eye with their own hand (small cracks between the fingers can
actually allow vision out of the “covered” eye). Children may also look around
commercially available occluders for the same reasons. Perhaps the best way to
obstruct the vision in the eye not being tested is to use a broad piece of tape,
ensuring the tape also covers the depression at the bridge of the nose ( Fig. 123.2
). To help ensure the patient is not “cheating,” the examiner should look back
directly at the child while standing by the chart indicating the letters or pictures.
If the child has glasses they should be worn during visual acuity testing. Any
child who can read a chart but shows reduced visual acuity should be tested using
a pinhole. If vision improves with a pinhole then the patient only needs glasses
and there is no organic abnormality causing the blurred vision.
After external examination and visual acuity are completed, the examiner can
then proceed with other procedures as indicated, such as upper lid eversion and
dilating the pupil. These techniques, along with the proper methods of examining
the retina and optic nerve using the direct ophthalmoscope, are discussed in
Chapter 114 Ocular Trauma .

FIGURE 123.2 A broad piece of tape can be used to obstruct the vision of the eye not being
tested. If the tape is not adherent to the bridge of the nose, the child can peek out by turning the
face to the side (right frame) .

Examining the Swollen Eye