Just came across this relatively short but useful document from the AOA written several years ago (issued July 13, 2021) that I hadn’t seen or heard of before. As with most concise documents of this nature, there are isolated statements that one might quibble with. For instance, ” … convergence insufficiency’—difficulty in keeping the two eyes aligned with one another—a condition a vision screening is not designed to identify …”. At first that might raise an eyebrow, but then you realize that the document is referring to the way vision screening is currently implemented, not an idealized screening. That should not diminish its impact.
The concerns addressed in the document became acute in the aftermath of the pandemic of 2019-2021, and many of the challenges remain. There are lots of potential sound bites worth noting, so I’ll share “The Science of Reading Begins with Vision” here in its entirety.
The Science of Reading Begins with Vision
Learning to read, and acquiring comprehension, require well-tuned visual systems. An educator may
struggle to teach reading fundamentals to a child who suffers from untreated (and often undiagnosed)
limitations of visual performance.
Babies are not born with the ability to perform complex eye movements. Most newborns have
rudimentary vision skills including tracking (visually following objects in space), convergence (moving the
eyes inward together), and divergence (moving the eyes outward together). Most infants can attain
fixation of the two eyes that enables rudimentary binocular depth perception (reaching out to touch a
nearby object) within six months.
By age 2, a child usually exhibits a useful degree of eye movement control (e.g., enough spatial recognition to allow the child to attain sufficient depth perception to recognize and put different shaped blocks into appropriate holes); still, precise eye movement skills (oculomotor) and binocular depth perception is continuing to develop through age 5 or 6, about the time children are learning to read.
When oculomotor and focusing development is delayed or stalled, children suffer decoding challenges and find it nearly impossible to draw meaning from the letters and words in written form; as words get smaller and closer together, the accuracy of eye movements can deteriorate further. Although some educators report that excessive fidgeting or covering an eye can be an indication of visual system problems, most often vision related problems are not apparent and have no outward signs. Rarely is the child aware of their own underperforming visual system making self-reporting of such issues highly unlikely.
Additionally, reading and decoding requires precise focus or “accommodation.” For this to happen
efficiently the ciliary muscle inside each eye at the base of the iris (colored part of the eye) must contract
precisely and remain contracted for extended periods of time to maintain the proper intraocular lens
configuration matched to the child’s reading distance. Children having trouble performing this function
can experience symptoms of blur, headache, tiredness, and discomfort when trying to read.
When a child with oculomotor deficiencies attempts to read, instead of building upon a functional visual
system that supports development of efficient reading skills, the seemingly simple, yet complex act of
changing the focal point to different words across the page can elicit conflicting sensory information. This is due to the connection between the visual system and the vestibular (semi-circular canals in the inner ear) which sends signals via the nervous system to the eye muscles through an automatic function known as the vestibulo-ocular reflex (VOR). The VOR maintains balance and controls eye positions (through innervation to six different eye muscles in each eye) while the head moves so that the gaze remains stable.
When the head rotates, the eyes rotate at the same speed but in the opposite direction. This allows the
gaze to be stabilized during rotation so that the image being looked at remains on the center of the visual
axis. When eye focus and movements are not exact and equally balanced, the brain receives conflicting
information that disengages decoding and disables cognition.
These vision difficulties might persist throughout life if not discovered early. For example, ‘convergence
insufficiency’—difficulty in keeping the two eyes aligned with one another—a condition a vision screening
is not designed to identify – can result in the child intermittently seeing double, experiencing eye fatigue
and/or avoiding close-up visual tasks, such as reading.
The complexity of reading and subsequent comprehension of the information to be processed cannot be
overstated. Ironically, many children with oculomotor and focusing issues may still have “20/20” vision
when tested on an eye chart at 20 feet. Consequently, they may do well in the initial stages of their reading development (phonics, fluency and vocabulary) because they can see and recognize letters and
combinations of letters. But in later stages, they will be unsuccessful at extracting meaning
(comprehension) from their reading material. Children must be able to decipher and recognize words on
the page, and they need to be able to make meaning of the words that they read. (1)
It is at this crucial second stage, “reading to learn,” that children with untreated or undiagnosed vision problems truly suffer. Children and educators are held back by preventive approaches that do not address the eye and vision health of children before teaching them to read. Two out of every five children taught reading have undiagnosed visual system disorders that slow or prevent decoding and cognition. While a need to build foundational skills that underlie oral reading fluency has been identified, there is also a complementary need to identify and treat all vision disorders as early as possible to allow for normal eye movement development. (2,3)
Even if some children with vision system problems eventually learn to read slowly, they do so with reduced psychomotor speed and are not able to retain information, because strain on cognition impairs short- and long-term memory. Without “recognition memory” of visual objects and spatial information, decoding is impossible. These children might not socially thrive or achieve executive function of high-level thinking and decision making. (4) These children might also be misidentified as having attention-deficit hyperactivity disorder (ADHD) and/or the need for an Individualized Education Plan (IEP) when their only problem is themneed for glasses or other treatments to their visual system.(5)
Often the educator and the parents are misled by their reliance on a vision screening which does not
evaluate any of the visual system concerns causing reading difficulties. As U.S. schools reach the end of a severely disrupted 2020-21 academic year, administrators and teachers will need to address students’ learning loss after months of remote schooling. Plans for recovery should include fully addressing children’s visual systems.(6) This examination should be performed by an eye doctor (doctor of optometry/optometrist) by age 3 to 5 and then annually, to help get reading right.(7)
References
1. https://www.edweek.org/teaching-learning/how-do-kids-learn-to-read-what-the-science-says/2019/10
2. https://nces.ed.gov/nationsreportcard/studies/orf/
4. https://www.cambridgecognition.com/blog/entry/what-is-cognition
6. https://www.aoa.org/news/clinical-eye-care/public-health/childrens-vision-summit-recap
The VisionHelp Blog 
Nice summary of visuomotor skills relative to reading. Unfortunately, the article, like AOA’s policy statement, and thus most of our kind, fails to appreciate the much more important subject of epigenetic reading strategy. Reading success is largely a function of attention and thinking strategy. I do not mean reading instructional strategy. I mean thinking strategy during attempts to read. Good, marginal, and poor readers think differently when reading. They are simply not engaged in the same thing. While all are attempting to read, they are doing distinctly different things. Poor Type III readers puzzle out words, mostly phonologically. They are serial phonologic decoders. Type II readers, while able to eidetically recognize words, convert text to speech prior to converting that self-generated speech to imagery. Type I readers make brief confirmatory glances at just enough text to validate their predictive imagery. Their mind leads, their eyes follow. Eyes lead mind follows in Type II & III readers. Duration of fixation is but an instantaneous glance in Type I, longer for text to speech translation in type II, and excessive periods for syllabic type III decoding. Type II readers fixate each word, Type III readers each syllable, and Type I readers make brief confirmatory glances at only a few nouns. Like nearly all behavior, environmental demand invites and shapes behavior. Observable behavior, including reading behavior is epigenetic. Genetics and general nurturing determines rate of brain maturation, environmental demand is the motive force that drives learning. When yet-to-be visually competent children are pressed with reading demand, they learn to meet demand by selecting from the developmental tools available at that point. Type III readers encounter reading demand without enough visual skill to eidetically store and recall text and default to serial decoding, often re-decoding to become the worst readers among us. Later we call them names, such as specifically reading disabled or dyslexic. Type II readers adopt subvocalization as an intermediary between text and imagery as they were not quite skilled enough to simultaneously recognize text and create imagery. Type I readers were lucky enough to possess adequate visual sophistication to recognize and convert text directly to imagery to become the best readers. Therefore, timing of instruction relative to visual development is the most important epigenetic factor in reading development. I argue that one of optometry’s most important contributions to society ought to be to increase the number lucky children. I suggest two lucky paths. 1. Improve early visual developmental skills by replacing screens with unstructured outdoor play. 2. Delay reading instruction until visual competence is established. While nearly everyone now understands # 1, nearly no one #2. Only we understand or should understand the technical reasons for both, especially #2. As the song goes, “I’ve looked at life from both sides now,” and concluded that our greatest failure as a profession is #2.
Steve, as a recovering Type 2 reader learning to be a type 1 reader, living with a type 1 reader, I appreciate the simplicity of this model and it’s power. Regarding the end of your post, what exactly determines “visual competence”? Is there a set of findings you expect to find in an evaluation? Fully adult levels of oculomotor, accommodative, and vergence skills? Is there a minimum expected level of certain visual information processing skills as well?
I’m also interest in how to assess visual competence?
A have another question.
Is it possible to move from type II reader to type I in adulthood, and how?
Are all of the children who learned how to read by them self even before school, type I readers ( assuming that they follow their natural readiness for reading)?