A combination of creativity and technological innovation allows optometrists to check your child’s eyes and diagnose vision loss without a child’s ability to know their letters. The same vision screening and diagnostic tools we use for children also support our work with adults who’ve never learned to read or write, who have processing disorders that make letter identification challenging, and nonverbal individuals.
Very basic vision testing should begin in your pediatrician’s office, as s/he uses standard vision screening tools to ensure your child has vision, can focus, and responds to certain visual stimuli. Pediatricians are also the first line of identification for common pediatric eye conditions such as crossed eyes or a lazy eye.
However, most pediatricians cannot discern vision issues that may go undetected without a pediatric eye exam by an optometrist. The American Optometric Association (AOA) cites that “…a vision screening by a child’s pediatrician or at their preschool is not the same as a comprehensive eye and vision examination by a doctor of optometry…They may miss as many as 60% of children with vision problems. Even if a vision screening does not identify a possible vision problem, a child may still have one.”
Testing Vision In Young Children Or Adults Who Can’t Read
As we mention in our post on the importance of pediatric eye exams, “Children are amazingly adaptive and can have pretty significant vision loss that goes unnoticed without a professional optometrist at the helm.” Therefore, we recommend bringing your child to the optometrist for their first vision appointment between the ages of three and five.
While they may not be able to read or identify letters, we use a range of tools and tricks to determine whether or not there is any noticeable vision loss and, if so, the degree of that loss so they are fitted with eyeglasses accordingly. If your child is going to preschool, schedule the visit before starting, as clear vision is essential to creating positive learning experiences. A child who can’t see well struggles with many of the matching, crafting, drawing, or writing exercises common to early education, which becomes frustrating and sets him/her apart from peers.
Here are some of the tools we use to check your child’s eyes before learning how to read.
Light and movement to check your child’s eyes
Directing our penlight into the eyes gives us a real-time analysis of pupil response. Sometimes this uncovers nervous system issues that affect vision. We also watch to see if the child can follow moving objects without moving their head.
Your vision is largely related to the anatomy of your eye, including the shape of the eye and how available light does (or doesn’t) focus on a single point – as well as where the lens focuses the light. Using the retinoscope tool, we can take a look into the eye to see how and where the retinoscope’s beam of light goes.
If you’re hyperopic (farsighted or longsighted), light focuses behind the retina. If you’re myopic (nearsighted or shortsighted), light is focused before it reaches the retina. Finally, if you have astigmatism, the light focuses at two different points, affecting your vision up close and at a distance.
Using precise measurements of how and where the light is focused, we identify the degree of correction required and can create a prescription that shapes corrective lenses to create a single focal point – leading to clear vision.
Preferential looking tests
These tests aren’t as objective as a retinoscopy, but they still provide important subjective information. Preferential-looking tests examine “vision acuity” or how well someone can see. This test uses a deck of cards with different black/white striped patterns. These patterns range in terms of thickness and density of lines. So, cards with the thickest black lines and spaces are easier to focus on, while squares of thin black lines and minimal white space between them require visual acuity, or they appear blurry. The back of all of the cards is a dull gray.
We’ll watch the child as s/he holds and looks at the cards. Most children focus on the side with the black lines as they’re more interesting than repetitive gray card backs. However, as the line patterns become more subtle, we may see a child spending equal time on the gray side as the lined side, which is a good indicator s/he can’t see the definition anymore. The point where the lines blur together too much to see a separate square provides critical information about the child’s acuity.
Autorefractors are another tool, like a retinoscope, that uses computer technology to measure refractive errors based on how an eye focuses (or not) at certain focal points. Again, however, this only works if the little ones are old enough or willing to sit still and look through the lenses for enough time to get a reading.
Symbol/shape eye charts
You’re probably most familiar with the Snellen eye chart, used since its creation back in the 1860s. The chart contains a series of capital (and lower-case) letters, arranged in lines from left to right, and that decrease in size from top to bottom.
If your child doesn’t know letters yet, the chart is useless. Instead, pediatric optometrists use symbol-based charts useful for children who are verbal and who can identify hearts, stars, circles, squares, triangles, a house, a tree, a flower, a bird, etc. Even if they don’t know all of their shapes by name, they can compare them to a chart in their lap and show us what they see, which yields essential data just the same.
Then we use the same technique we do with any eye exam, trying “lens 1?” or “lens 2” to see which eyeglass prescription is most likely to correct their vision loss.
Focusing one eye at a time
We’ll ask your child to focus on something on the other side of the room while covering one eye, and then the other, and then with both eyes. We do the same thing with objects in the close-up visual field. This helps us to see how well the eyes are working together.
Ready To Schedule An Appointment To Have Your Child’s Eyes Checked?
Is your little one ready for his/her first eye exam? Or, were you referred to us by your pediatrician? The team at the Atlantic Eye Institute does everything we can to make our appointments fun, engaging, and comfortable for toddlers, young children, and their parents. Contact us online to schedule an exam. Or, give us a call at (904) 241-7865.