Reading is one of the most important life skills that allows us to visually perceive and process written and printed information. Literacy usually develops in childhood during elementary school. Literacy development depends upon individual neurobiological, cognitive, and psycho-social factors, as well as various external factors, including one’s educational system, the complexity of one’s language, etc. Reading difficulties are typically associated with impairments in phonological awareness; however, reading difficulties may also be the result of impairments in visual attention, visual perception, eye movement coordination, and visual function efficiency. Any impaired function may interfere with reading processing. Optometrists and vision specialists sought answers to the following questions: What methods are available to minimize the effects of perceptual impairments on reading ability in school-aged children? How are visual perception disorders correlated with reading difficulties within the population of school-aged children? Is it possible to create a reliable diagnostic tool – in Latvian – to methodically evaluate reading speed impairments associated with visual perception disorders? These are the questions that drove this work, the purpose of which is the investigation of the relationship between reading speed and grapheme perception speed (in Latvian), as well as eye movement characteristics and coherent motion perception. This study also includes a demonstration of the relationship between near-distance visual perception impairments and reading difficulties in school-aged children.
The results of the study are based on epidemiological screening of visual functions in school-aged children (n = 11,000), with additional testing for reading ability, eye movement development, and coherent motion perception thresholds. All testing was executed with the use of specially developed computerized tests.
The study includes a quantitative evaluation of reading speed development in school-aged children by analyzing reading processing (in Latvian) through the use of a variety of visual perception and cognitive tasks. The results reveal that both cognitive and motor processes limit the amount of information perceived per unit of time. The perception of words is 27% more efficient than the perception of nonwords, which demonstrates the effect of semantics (meaning) on information processing. The formula for the evaluation of verbal reading speed (number of graphemes per second or gr/s) in Latvian:
ORFT=0.06*a+1.26*b+2.84*c–0.0048*J*(a*b*c)–0.18; (R2 = 0.77),
where a – word recognition (VWR) (gr/s), b – DEM (V) ratio (gr/s), c – DEM (H) ratio (gr/s), and J – coefficient to dovetail the unit 1 s2/gr2.
The cognitive features of the children’s reading language do not affect coherent motion perception; it develops slowly and steadily. 16% of school-aged children who have been categorized as slow readers exhibit high perception thresholds. With respect to motion perception, the use of low speed dot velocities (2 deg/s) facilitates distinguishing slow readers from faster readers. The study demonstrates that inadequate visual functions are responsible for slow reading rates in 7 % of school-aged children. The essential visual functions are visual acuity at near distances, accommodation response time on -2.0 D, vergence response time on 8 Δ base in, heterophoria, and steropsis.
Keywords: reading speed, visual perception, grapheme, school-aged children
