Health encyclopaedia - Alphabetical Topic List

| A | | B | | C | | D | | E | | F | | G | | H | | I | | J | | K | | L | | M |
| N | | O | | P | | Q | | R | | S | | T | | U | | V | | W | | X | | Y |

How is it performed? of Hearing and vision tests for children

Hearing tests

Newborn babies are usually screened using the otoacoustic emissions (OAE) test. A tiny earpiece is placed in the baby’s outer ear and quiet clicking sounds are played through it. This should produce reaction sounds in a part of the ear called the cochlea, and the computer can record and analyse these. It is painless and can be done while the baby is asleep.

Sometimes clear results are not obtained from the OAE test. A different method can be used, called the automated auditory brainstem response (AABR). Small sensors are placed on the baby’s head and neck, and soft headphones are placed over the ears. Quiet clicking sounds are played through the earphones and a computer analyses the response in the brain, using information from the sensors.

A health visitor carries out a distraction test for infants up to about 7 or 8 months old. If hearing is normal, the child will turn his or head to respond to the noise. In children 2 years and old, the health visitor may test hearing by whispering the name of an object. The child has to point to the correct object. This is called the McCormick Toy Test.

At school age (between 4 and 5) all children should have the hearing ‘sweep’ test. This an audiogram test across the main speech frequencies (high and low pitches) and using sounds of different volumes (loudness), which are played through earphones. The child has to indicate whether they have heard them, or perform various actions depending on the type of noise.

Vision tests

The eyes of newborn babies are examined for any obvious physical defects, include cross-eyes, cloudiness (a sign of cataracts), and redness.

  • The pupil reflex is checked by shining a light into each eye from a distance of 10cm. The pupils should automatically shrink in response to brightness.
  • A test called eliciting the red reflex is carried out using a magnifying instrument with a light on the end, called an opthalmoscope. Light is directed into the baby’s eyes and a red reflection should be seen as the light is reflected back. If the reflection is white instead, the child should be referred to a specialist immediately, as it can be a sign of a cataract or other eye condition.
  • To test whether the newborn baby pays attention to visual objects, the midwife or doctor catches the baby’s attention with an interesting object such as a face, then moves it and sees if the child’s eyes follow.

In older babies and toddlers up to around 2 years, the focus and sharpness of eyesight can be checked using the rolling ball test. This involves rolling differently sized white balls rolled across the floor, and shows the range of vision and how small an object can be spotted. Another simple test is to use small blocks or tiny objects like buttons, to find out whether the child can see them and reaches for them. Each eye can be tested separately by covering the other with a patch. Older children can be asked to count the number of fingers held up. From age 5 years, charts with rows of letters of decreasing sizes can be held up at a distance of several metres, and the child reads out as many of the letters as he or she can see. These charts are called Snellen charts or logMAR cards.

To test the range of movement of each eye, the child’s attention is drawn to an interesting object, which is then moved to eight positions: up, down, left, right, and half-way in between each of these points. The test involves checking how well each eye follows and how far the movement of the eye stretches in each direction.

In children 5 years and older, the visual field is often tested with the ‘wiggly finger’ test. Each eye is covered in turn, and the examiner gradually brings a wiggly finger into the child’s field of vision.

Colour blindness (colour vision deficiency) tests are not carried out at primary school age, but usually around age 11 if a problem is suspected. These use the Ishihara colour vision tests, which involve images made up of two different colours of dots. If colour vision is normal, the child will be able to recognise the letter or number that is highlighted. A child who cannot tell the difference between two colours (such as red and green) and therefore cannot see the picture, may have a colour vision problem.