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PEDIATRIC EYE EXAM BASICS: PART 2

A LOOK AT THE EVALUATION OF THREE SYSTEMS

AFTER REVIEWING any specific concerns a parent has about his or her child, proceed with the eye exam in much the same way you would for an adult. Of course, the child’s level of understanding, ability to communicate and attention span can vary widely, all of which can affect the way you go about obtaining the results.

In this column, I discuss how to evaluate the first three systems.

1 VISUAL ACUITY

Generally, before covering one eye, which can be a distraction, begin testing the young patient’s (children younger than age 6) acuity with both of his or her eyes open to determine at what level the patient can participate in the exam. From there, the exam can be done with targets, requiring the child to provide either non-verbal or verbal responses, depending on his or her ability.

If the child is an infant or non-verbal, use a forced choice preferential looking method, such as Teller Visual Acuity Cards, Richman Paddles or the Broken Wheel Test, matching the Visual Evoked Potential (VEP) and the sweep VEP for infants.

Teller Visual Acuity Cards are based on the preference of looking at a striped grating pattern vs. a uniform gray field. The Richman Paddles employ a similar principle with one paddle showing a smiling face and the other one blank. The Broken Wheel Test shows broken wheels, represented by a Landolt C, and non-broken wheels. Matching, using LEA symbols (circles, squares, apples, etc.) and Cardiff acuity cards, which use vanishing optotypes, can also be an effective means of assessing visual acuity. VEP can provide an estimate of visual acuity for infants and young non-verbal patients, and sweep VEP is used to detect the probability of amblyopia in infants.

If the young child is verbal, use visual acuity tests that show objects, such as a bird, as most young children learn to recognize such items prior to numbers and letters. Incidentally, most verbal acuity tests for young children are designed for use at a distance of 10 feet.

Use the traditional Snellen chart for older verbal children (age 6 and older). Although it’s common for eye doctors to isolate or box off one letter at a time to maintain patient focus, if you suspect a patient has amblyopia don’t use this method. The reason: It can mask the condition. Instead, compare how each eye reads a whole line of letters, or use individual letters with crowding bars around them. For children who reverse letters, use the capital letters “H,” “O,” “V” and “T” because if they appear reversed, the child will still be able to name them.

2 EYE MOVEMENTS

To assess fixations, pursuits and saccades in young children, use finger puppets. You want to ensure nystagmus isn’t present, and note any restrictions or limitations in all positions of gaze.

To evaluate eye movement in school-age children, use Alphabet Pencils splitting the midline for saccades. Take careful note of whether the patient is overshooting or undershooting the target, has loss of fixation, excessive head movement and/or difficulty crossing the midline. At the primary care level, pursuits and saccades are often recorded qualitatively. That said, if you want to quantify pursuits and saccades, use a scale, such as NSUSCO, which can be found at bernell.com. The two most important times to quantify pursuits and saccades: (1) when the parent reports the child loses his or her place when reading and (2) when the young patient has sustained a concussion. Also, to document age-equivalent performance for eye movements, use the DEM or K-D tests, which can be acquired from Bernell.com as well. When a child is suspected of having a developmental delay or he or she has trouble keeping place when reading, you would want to document age-equivalent performance. Both tests involve rapid number naming and are standardized.

3 REFRACTION / ACCOMMODATION

Employ a retinoscope for objective refractive status at distance and for accommodative responses at near. Near retinoscopy is most commonly performed through the monocular estimation method (MEM). When using MEM or near-retinoscopy, in general look for symmetry between the two eyes in terms of quality and stability of the reflex, in addition to the lag value. Cycloplegic refraction can add insight, particularly in cases of suspected latent hyperopia and in the presence of esophoria.

With regard to accommodation facility testing, use +/- 2.00 lens flippers. Children between the ages of 8 and 12 should be able to clear five cycles per minute on average, while patients older than age 12 should be able to clear 10 cycles per minute.

FOUR TO GO

In Pediatric Eye Exam Basics: Part 3, the last of this series, I discuss the evaluation of binocular vision, color vision, vision development and eye health. OM

LEONARD J. PRESS O.D., F.A.A.O., F.C.O.V.D., is the optometric director of the Vision & Learning Center in Fair Lawn, N.J. He specializes in pediatric vision. Dr. Press completed his residency program in pediatric optometry at the Eye Institute of the Pennsylvania College of Optometry, and he served as chief of the pediatric unit of the Eye Institute. In addition, he’s a Diplomate of the AAO and has written three textbooks encompassing pediatric optometry and is a Diplomate in the Pediatric Optometry/Binocular Vision and Perception section of the AAO. Email him at visionlecture@gmail.com, or visit tinyurl.com/OMcomment to comment on this article.