Amy, an outgoing and bright 4th grader, had done very well in 1st and 2nd grade, but in 3rd grade her reading scores had begun to drop, and by 4th grade she was struggling. Amy clearly was intelligent, but even with her parents working with her every night, her reading skills were not progressing. A team assembled at the school to decide how to help.
Eye chart tests at the pediatrician's office showed that Amy's eyes were fine, but Amy's parents suspected a "missing piece" to her academic skills and landed in Dr. Liddicoat's office. A complete eye exam showed that Amy indeed had 20/20 vision; however, her eyes were not focusing correctly when she looked up close. In addition, her eye muscles had difficulty moving in a systematic, coordinated fashion. Upon hearing the diagnosis, Amy's eyes filled with tears. Her mom said, "Honey, don't worry, I'm sure the glasses will look fabulous on you."
Amy replied, "It's not about the glasses, Mom. I'm just glad I'm not stupid after all."
Vision disorders are the fourth most common disability in the United States, affecting some 10 million children nationwide (National Parent Teacher Association, 1999). Despite the preponderance of problems, it is believed that up to two-thirds of all children entering school have never had an eye test. Of the one-third who have, about 50 percent do not receive the recommended follow-up (Preslan & Novak, 1998).
Recent research concludes that roughly 80 percent of what children learn in their early school years is visual (American Optometric Association, 2000)—consider, for example, the eye's role in reading a book, writing an essay, following a teacher's writing on the board, observing a science experiment, and doing a math problem. Clearly, more comprehensive screening and treatment of vision disorders is needed.
A Comprehensive Look at Vision
Typically, we think of vision quality as a ratio with 20/20 being "average," meaning one can see from 20 feet away what an average person can also see from 20 feet away. While helpful, this simple approach often brushes aside the complexity of the human optical system. Four elements of the visual system affect a student's ability to see clearly: general eye health, refractive error, binocular coordination, and visual processing skills.
Eye Health
The health of the eye, including the eyeball and the muscles controlling it, affects how clearly a person can see. Even something as easily treated as dry eye can affect a child's clarity of vision. Often, such eye conditions have no associated pain and therefore go overlooked in children. Compounding this, children rarely report their symptoms because they don't know what's normal. They assume everyone sees the same way they do.
Refractive Error
Various genetic conditions, including the size and the shape of the eye, affect how clearly one sees at a specific distance or how hard one's eyes have to work to see clearly. Refractive error, generally identified through routine screenings and teacher observations, consists of three categories: myopia, hyperopia, and astigmatism.
Myopia (nearsightedness). Individuals with myopia have difficulty seeing at longer distances. Students in school, for instance, can't see the board but see perfectly fine up close. These are the students squinting at the board! Standard screenings—and teachers—pick up these cases most of the time. During the school years (6–18 years old), myopia prevalence soars to more than 20 percent of students (Sperduto, Seigel Roberts, & Rowland, 1983).
Hyperopia (farsightedness). At the opposite end, hyperopia is characterized by difficulty viewing objects up close. Students must work extra hard to see clearly, which causes muscle strain, fatigue, and eye discomfort. The most common sign of hyperopia is, not surprisingly, an aversion to reading. Teachers have a difficult time identifying these students, because they typically do not complain about blurry vision. Typical vision screenings with an eye chart often fail to catch these children as well.
Astigmatism (blurry vision at any distance). This condition, like the other two, depends on the size and shape of the eye, but in this case the distance from the object viewed is irrelevant. The following story from Dr. Liddicoat's practice illustrates the effects of astigmatism.
Megan came in for her first eye exam at age 15. Her parents were unaware of any problems, but when questioned directly about problems with her vision, Megan admitted that her math teacher writes too small. By the time Megan deciphers the writing, the teacher has moved on to something else. The teacher had moved her seat closer to the front of the room, but Megan said, "I had just as much trouble when I sat right next to the board." This is not unusual for individuals with astigmatism. There is no good distance where their vision becomes clear; only glasses or contact lenses can provide the clarity they need.
Binocularity
If the two eyes do not work together, even a child with healthy eyes and no refractive error may not be able to see clearly. The muscles on the outside of the eyes should learn how to line the two eyes up and track together by the age of 6. If the brain-to-muscle pathways do not develop properly, the child is left with binocular dysfunction. Hoffman (1980) reports that more than 85 percent of children with learning disabilities who are referred for an eye exam have a vision impairment that adversely affects one of the three major binocular functions: vergence, tracking, and accommodation.
Vergence dysfunction. Our eyes are designed to work as a team, but each eye functions independently. When we look at something, each eye records an image. The two images are transmitted through the optic nerve to the brain, which combines them into a single image. For the visual system to work, each eye must aim at the exact same point so that the images are identical. If the eyes are not aimed correctly, the brain can't fuse the images, causing double vision. It is estimated that 10 percent of school-age children have a fusion problem (Rouse et al, 1999). The increased demands of schoolwork and prolonged periods of reading can exacerbate symptoms in older children.
Oculomotor (or tracking) dysfunction. The fine eye movements required to accurately follow a line of print demand the highest level of movement precision known to the human body. There are several different types of eye movements, but the ones we are interested in are pursuits andsaccades. A pursuit movement allows the eyes to follow a moving target, like a baseball, whereas a saccadic movement allows the eye to move accurately from one fixed point to another, such as from word to word (or from the end of one line to the beginning of the next line) when reading. Difficulties with ocular control complicate the process of reading and often look like a learning disability, rather than a vision issue.
Accommodative dysfunction. The term "accommodation" refers to the ability to maintain a clear, sharp image for an extended period of time, as well as to rapidly and accurately shift between objects at different distances, such as from desk to chalkboard and back. A student who is having difficulty with clarity of the words on a page will instinctively pull the book closer or lean over the page on a desk. However, the closer one gets to the visual target, the more the ciliary muscles in the eye have to work.
When the eye has to read in this near position for a sustained amount of time, a muscle spasm tends to occur in the ciliary muscle, keeping the lens "over-focused" so that when the student looks across the room, his or her distance vision is now blurry. In contrast, other students may have accommodative insufficiency, causing a relative inability to keep things in focus up close. With accommodative insufficiency, we see a great deal of visual fatigue and excessive blinking.
Visual Processing
Visual processing is the ability to interpret, analyze, and remember visual images. Visual perception factors into recognizing and recalling words, even when a number of other cues are available. It has a role in sorting, classifying, and matching symbols as well as left-right directionality awareness. It affects a student's ability to organize writing or drawing on a page and to understand concepts related to geometric shapes and numbers as quantities. A student's skill in visual processing contributes profoundly to a student's preferred method of learning. Students with a visual processing deficit must rely heavily on auditory skills when learning, and they perform better when tested orally.
Several studies report that visual-perceptual-motor ability significantly correlates with reading readiness in kindergarten and with reading achievement in the early primary school grades. Goldstand, Koslowe, and Parush (2005) posit thatvisual function significantly distinguishes between children with and without mild academic problems, as well as on visual-perception scores. The high occurrence of visual deficits among participants warrants consideration of vision deficits among schoolchildren with academic performance difficulties.
What Schools Can Do
An undiagnosed or untreated vision disorder clearly leaves a child behind in the classroom. In fact, Maples (2003) concluded that factors related to a student's vision are significantly better predictors of academic success than is race or socioeconomic status. Several childhood vision disorders, left untreated at a young age, result in permanent visual impairment throughout adulthood. So what can professional educators do about it?
A Checklist
- Does the student have difficulty holding the head still while tracking?
- Does the student experience nausea or dizziness while reading?
- Does the student complain of pain or discomfort in the eye?
- Does the student exhibit redness or watering eyes?
- Does the student rub the eyes often?
- Does the student suffer from headaches after engaging in visual work?
- Does the student lose his or her place often?
- Does the student have an aversion to reading?
- Do the student's eyes "bounce around" while reading or performing close-up work?
- Does the student display an inability to read aloud despite high comprehension rates?
- Does the student frequently make omissions, substitutions, or careless errors in reading?
- Does the student avoid engaging in close-up work?
- Does the student get "lost" when looking from the board to a paper and back to the board?
Vision Screenings
If a student is having vision-related difficulties, a screening can be crucial to academic success. In a longitudinal study of struggling readers, Young, Collier-Gary, and Schwing (1994) discovered that visual factors are a primary cause of beginning reading failure. Unfortunately, most current school screenings, which focus on acuity, are inadequate. One study (Grisham, Powers, & Riles, 2007) found that 80 percent of identified "poor readers" (two or more years below grade-level) had poor eye muscle skills or near focus problems. This contrasts with the low percentage (17 percent) who had poor acuity.
Another study (Powers, Grisham, & Riles, 2008) noted the high prevalence of "poor readers" who scored below the 50th percentile on a tracking test. This screening, not typically given in schools, was also found to accurately distinguish those students who have an identifiable learning disorder from those students who simply lack eye muscle control.
Vision screenings should be used to identify those students who are struggling because of a measurable and treatable visual skill. A diversified and comprehensive screening plan can identify more precisely each child's needs—allowing us to address vision issues more directly and avoid unnecessary referrals to special education.
Spectacles
Glasses themselves cannot correct every malady outlined here, but many students don't wear their glasses when they need them, for a variety of reasons—they may be lost, the glasses may be scratched or damaged, the student may feel self-conscious about them, or other children may tease the student. As educators, we have an obligation to influence our students' glasses-wearing practice.
Perhaps many of you have already addressed this in your classrooms, but if you haven't, find out what you can do to help make sure your students are wearing their glasses when they are supposed to. Are you informed as to whether each child is to wear glasses for distance viewing, close-up work, or full-time? Many teachers display color-coded tags on the student's desk or have a large, glasses-shaped placard that serves as a visual cue of the student's need.
A Place to Start
The list of vision problems and symptoms we've provided is by no means comprehensive, but we hope it gives educators a place to start when observing students with academic problems. An awareness of the wide array of vision difficulties can help educators distinguish between struggling students with a learning disability and those with manageable vision disorders. Armed with this information, we can begin to address the needs of the whole child.
