Eye movement efficiency in normal and reading disabled elementary school children:
effects of varying luminance and wavelength

Reading comprehension (percent correct) for normal and disabled reader three filter conditions:
clear, gray, and blue.

Dr Solan's and Dr Brannan's report in the Journal of the American Optometric Association says, "Since not all of the 27 RD children improved with blue filters, we postulate that the 75% of the RD children who improved in visual efficiency with the blue filter represented those who may have a transient deficit. It is remarkable that in previous studies improvements in reading comprehension using blue filters were observed in 75%~ and 87% 2 of RDs. In addition, Lovegrove et al. reported that 75% of RD children-compared with 8% of the controls-exhibited visual deficits involving longer visual persistence and lower flicker fusion rates, as would be expected with a magnocellular defect.
The rationale for this study is based on previous contemporary investigations that provide abundant anatomic, physiologic, and psychophysical evidence to support the hypothesis. Just as our earlier studies proposed that a significant link exists between wavelength of light and reading comprehension and luminance and reading ability, the current clinical investigation broadens the concept of transient system deficit to include its potential impact on oculomotor efficiency. The blue filters improved oculomotor efficiency significantly without comprehension loss in 75% of the RDs. Although some inconsistencies remain in M-cell research, there appears to be sufficient evidence to accept the premise that a defective magnocellular pathway may be one factor in the delayed development of visual processing and reading skills in some elementary school children."

ABSTRACT

Background: This investigation examines the question of whether decreasing wavelength of light and/or reducing luminance benefits oculomotor efficiency in normal and reading disabled (RD) children.
Methods: Two groups of children were identified as normal or disabled readers using standardized reading tests After suitable practice, eye movements were objectively measured with the Visagraph II as each of the subjects silently read a series of three different selections at their independent reading level with clear (control), gray, and blue filters. Four variables were measured for each subject Data were analyzed using a repeated measure ANDVA and post hoc tests.
Results: The standardized reading tests significantly differentiated average from poor readers using grade scores and percentiles. Initially, with clear filters, eye movement scores of normal readers were superior to disabled readers for fixations, regressions, and rate of reading Among the RDs-but not the normals-the three variables improved with the blue filter when compared with the clear filter; number of fixations and regressions were significantly lower, and rate was significantly higher Dray filters yielded no significant changes Improvement with the blue filters normalized the three variables in that there were no significant differences between normal and disabled readers
Conclusion: This investigation confirms a link between wavelength of light and eye movement efficiency in reading Blue filters resulted in a significant improvement in the number of fixations and regressions and rate of reading in RD children The outcome droadens the concept of transient system deficit established in previous research to include the effect on oculomotor efficiency The educational implications of this study are of special interest to optometrists
Key Words: Transient processing, sustained processing, parallel processing, reading comprehension, reading disability, eye movements, wavelength, luminance, chromatic filters

Volume 69/Number 7/July 1998                          Journal of THE AMERICAN OPTOMETRIC ASSOCIATION