fixate), (d) eye movement control (where to move), and (e) models of eye movement

control. His research confirmed that the average span of perception can be determined by

computing the number of words per fixation. As a result, slow reading speed may be

highly correlated with eye movement.

Visual processing

 Visual processing skills refer to a group of visual cognitive skills used for

extracting and organizing visual information from the environment and integrating this

information with other sensory modalities and higher cognitive functions (Scheiman,

2002). Visual processing skills are classified as visual spatial skills, visual analysis skills,

and visual motor integration skills. As mentioned earlier, Adams (1990) stated that

reading is accomplished through complex and interrelated processes, one of which is the

visual process. Therefore, when determining the relationships between vision and

reading, tests of visual processing should be involved rather than limiting the evaluation

to eye health and visual acuity. For a skilled reader, the identification of a printed word

begins with a visual process that operates on the visual forms of letters that make up a

word and then instantaneously generates other processes including the phonological

decoding process, to which printed letters and the sounds of the language correspond

(Adams, 1990). Many researchers have considered visual processing one of several

factors that may affect children's reading abilities. There are some concrete examples.

Kavale (1982) used meta-analysis to establish the relationship between visual-perceptual

skills and reading. In his review, the 161 studies produced a total of 1,571 correlation

coefficients, of which 1.062 indicated the relationship. Across all visual perceptual skills

(visual discrimination, visual memory, visual closure, visual spatial relationship, visual-

motor integration, visual association, figure ground discrimination, and visual-auditory