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  PEDIATRICS

PEDIATRIC EYE EXAM: PART 3

A LOOK AT THE EVALUATION OF FOUR SYSTEMS

AT THE primary care level, doctors get hints of developmental milestones that could lead to the early detection of abnormalities and disabilities. Indicators that a child may be on the autism spectrum, for example, can be found during the vision development portion of the pediatric eye exam. The earlier you are able to identify issues and intervene, the better the long-term outcome for the child, making vision development assessment the most significant aspect of a pediatric eye exam.

The vision development assessment is part of the pediatric eye exam, along with tests for binocular vision, color vision and eye health. In this final installment of the basics of a pediatric eye exam, I discuss all of these.

1 VISION DEVELOPMENT

Visual perceptual tests that provide percentile ranks are considered the gold standard for testing vision development. You can gain valuable insights about vision development, however, just by being an astute observer. Specifically, note how an infant or preschooler is able to maintain posture or muscle tone sitting in a parent’s lap. Also, watch how the child walks down the hallway or gets into and out of your exam chair. These are important motor skills. When you hand a young child the occluder and ask him to cover his right eye, is he confused about which is his right? Confusion about laterality beyond age 7 should raise a red flag that his vision development is not on track.

When you conduct these primary care tests and the child exhibits uncertainty or confusion, ask about his academic performance. If a parent has concerns about a child’s performance or development, and you don’t provide more extensive testing in your practice, it is crucial to find a colleague with whom you can co-manage the child.

2 BINOCULAR VISION

First, determine whether the eyes are aligned. You can make use of the corneal light reflexes through the Hirschberg test, which screens for strabismus, as a starting point. With the room lights dimmed, hold a light source, such as a transilluminator, on the midline about two feet from the child’s face. Position yourself below the line of sight of the child, and have something of interest, such as a toy, across the room when performing this test in order to maintain the child’s attention. Accommodative esotropia is detected when the child fixates on something of interest at near. I like to use a Big Bird finger puppet with an inserted disposable penlight for this, as it provides a good accommodative target and a corneal light reflex at the same time.

If the eyes are aligned, measure the phoria and fusional vergence reserves. When the child isn’t able to perform these tests traditionally behind the phoropter, use a red Maddox rod that has a built-in rotary prism in free space held over one eye, while the other eye fixates on a light at distance and then at near. To get the patient’s attention, I tell him, “We’re going to create a laser beam together.” To measure fusional reserves, use a prism bar while the child looks at a target of interest. If your patient isn’t able to tell you when he sees double, watch for his eyes to look back and forth as the target splits into two to determine whether his eyes are working together.

Illuminated Big Bird acts as a target for near testing.

Lastly, the results of stereopsis testing provide an index to the quality of binocular vision.

3 COLOR VISION

When a child is old enough, typically older than age 6, administer the Farnsworth D-15 color cap test, which involves the sequencing of colors, but not just their discrimination. Children younger than age 6 typically find this test too complex. For preschoolers or children with visual processing problems, tests such as the Ishihara Pseudoisochromatic plates may be easier to perform. These tests require a child to have number knowledge and the ability to follow the path of colored dots within an outer circle that form a shape or number. If a child doesn’t have number knowledge or the perceptual skills to identify the figure from its background, use a matching game. Specifically, use a pointer stick to point to a particular colored dot, and ask the child to show you the dot with the same color.

Red Maddox Rod with Risley Prism.

Prism bar for bincoluar vision testing.

Test target used for distance.

4 EYE HEALTH

Keep in mind how intimidating a lot of the instruments used to assess eye health look to the child. To put young patients at ease, consider referring to your biomicroscope as a giant flashlight.

Time is of the essence in this phase of the exam. To dilate the pupils with pharmaceuticals, remove the caps first so one bottle is ready to go right after the next. Tell the child that the first drop might sting a tiny bit, but the second drop removes the sting right away. You can also ease the child’s fears by putting a drop on your finger, or mom or dad’s finger, to show that it’s wet just like a raindrop.

Children will often sit still for the slit lamp evaluation and fundus photography if you can show them the magic of what their eyes look like inside. Tonometry, of course, is never fun for the child or the examiner. When doing NCT, do it with eyes closed first to show that it’s just a puff of air. When doing Goldmann tonometry, have an assistant hold the illuminated Big Bird puppet light in front of the eye not being measured.

END OF THE MAGIC

In this three-part series, I have divulged tips and tricks to the pediatric eye exam. From sending parents the patient form in advance to the quick hand needed for dilating the patient’s pupils, the pediatric eye exam requires some advance preparation to go smoothly. But if all goes well, parents, patients and the practitioner all leave the exam room happy. 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 is past president of COVD, specializing 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 before serving as chief of vision therapy at S.U.N.Y. College of Optometry. He 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.