The general health of adults and juveniles with a visual-perceptual subtype of dyslexia known as Irlen Syndrome (IS) was assessed by a self-administered questionnaire, and the responses were investigated in relation to changes in urinary and plasma biochemistry. The prevalence and severity of a number of the symptoms assessed by self-report for a one week period showed significant differences when compared to their control peers. Increases in symptoms for the IS subjects indicated possible problems with the dysregulation of the immune system, photophobia, neurocognition, mood and with muscle cramps and twitches. The significant increases in these problems suggested that in IS, reading difficulties were accompanied by reductions in the general "well-being" of the individual. The reported severity of both the IS and the general health symptoms were associated with alterations in the levels of specific plasma lipids and urinary metabolites for the IS cohort. The results suggested that in IS the general health of the individual may be poorer and that these changes, along with the symptoms that define the syndrome, may be associated with anomalous biochemistry. Examination of these associations provides further insight to understanding the aetiology of this learning disability.