Scientists from the Research Laboratory of Electronics and the Departments of Biology, Electrical Engineering, and Computer Science at M.I.T. Cambridge, Mass. have collaborated in an investigation of the peripheral and foveal (central) vision of 5 dyslexic adult subjects compared to 5 normal readers. Two letters, one at the fixation point and one in the periphery, at varying distances apart (eccentricities), were presented simultaneously and the scores for the correct identification of the single peripheral letters in the two groups were compared.

At 2.5° eccentricity (near central fixation point) the scores of normal readers were the higher. Correct identification fell off with increasing eccentricity (2.5 to 12.5 degrees) in both groups but the fall off was slower in severe dyslexics than in normal readers. At 7.5° eccentricity (peripheral field vision), the scores of dyslexic subjects were higher than those of normal readers; i.e. they were better at perceiving briefly presented letters in the periphery.

When a string of three letters was substituted for the single letters in the periphery, the severe dyslexic could identify none of the letters at 2.5° eccentricity (near central vision) but at 5° and beyond (peripheral vision) his identification of letters was near normal. After a program of exercises involving spatial organization and eye-hand co-ordination and the use of a simple device to utilize his optimal peripheral vision in reading, the performance of the severe dyslexic subject showed improvement after 4 months up to a 10th grade level. [1]

COMMENT: These interesting findings and suggested treatments will undoubtedly bring joy to the optometrists and those who favor the Kephart and Frostig methods in the management of dyslexia. Kephart’s three-crucial perceptual skills to be mastered as prerequisites to reading are form perception, spatial discrimination, and ocular control. If these skills are underdeveloped, according to Kephart, the child will develop faulty intersensory integration abilities and concept formation. Frostig, similarly, maintains that adequate perceptual functioning in young children is the foundation on which later school success depends. Critics of these methods state that evidence from research studies does not support their value in reading remediation. However, several authors have emphasized abnormalities of eye movements, tracking, and visual fixations as a characteristic of dyslexics and further studies are needed.

The authors, Geiger and Lettvin, conclude that in dyslexics, there is an interaction between foveal and peripheral vision that degrades the normal ability to read in the foveal field. Dyslexics have masking or suppression of letter discrimination in the central foveal field and better than normal peripheral visual identification of letters. They suggest that dyslexics should be taught to read by use of their peripheral vision. Neurologists might argue alternative explanations for the findings based on changes in attention or cortical visual organization but the study offers a simple and practical method of treatment that is worthy of trial in a larger number of younger subjects. The results could be different in children from those in adults, aged 18 - 25, used in this study (See PED NEUR BRIEFS 1 (1) :5)