The purpose of this study was to investigate the prevalence and types of non-strabismic accommodative and/or vergence dysfunctions in primary school children, and to determine the relationship of these dysfunctions to academic achievement. A total of 1031 parents and their children aged 9-13 years responded to the College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. Of these, 258 children whose visual symptom scores were> or =20 were identified for further evaluation. Comprehensive eye and vision examinations were provided to the children who met the eligibility criteria (114 of 258): eligible symptomatic children were those without amblyopia, strabismus, ocular and systemic pathology, and contact lens wear. Children were also excluded if they had visual acuity poorer than 20/25 in either eye or vertical phoria >1 prism diopter. The results showed that 82 of 114 (71.9%) of criteria-eligible symptomatic primary school children had non-strabismic accommodative and/or vergence dysfunctions. In addition, a significant relationship was found between these dysfunctions and academic scores in every academic area (reading, mathematics, social science and science) in the total sample. Therefore, accommodative and vergence functions should be tested for all school children who have visual symptoms and/or academic difficulties. Additional study is needed to determine if improvements of accommodative and vergence functions also improve academic achievement.