Abstract
Purpose:
To examine whether reports of ocular discomfort by school children with emmetropic refractions are primarily related to binocular vision anomaly(s) (BVA). Also, to investigate whether the Convergence Insufficiency Symptom Survey (CISS) can be utilized to identify suspect BVA and separate accommodative and/or convergence anomalies.
Methods:
Children aged 8 to 16 years in grades 3 to year 10, were recruited from a private school in Melbourne, Australia for a basic vision screening. Tests included visual acuity for distance and near, non cycloplegic retinoscopy and subjective refraction, stereopsis and cover test. Those children classified as emmetropic and without ametropia, astigmatism, anisometropia, amblyopia, strabismus, ADHD or learning difficulties, also underwent a further detailed binocular vision assessment including a battery of accommodation and convergence tests and completed the CISS.
Results:
Of the 247 primary and middle school students screened (participation 72.6% of all enrolled, mean age 11.5 ± 2.2), 74.5% (n=184) emmetropes were included for binocular vision assessment. In those who had their binocular vision assessed, 54.3% (n=100) had normal binocular vision (NBV) and the remainder (45.7%, n=84) were suspected on standard clinical tests of having a BVA (35.7% convergence anomaly, 10.7% accommodation anomaly and 53.6% mixed anomaly). BVA groups including accommodative dysfunction had significantly higher symptom survey scores (p<0.01) compared to the NBV group. Results of the 15 question survey revealed 4 redundant questions. The remaining 11 questions were further analysed using factor analysis, whereby two major factors were extracted from the CISS variance, one associated with ocular discomfort and the other relating to cognitive consequences.
Conclusions:
This study suggests that it is common in a non-selected group of emmetropic school children to find children with suspected BVA who warrant referral based on binocular vision signs and symptoms. Also, this study suggests that the CISS is useful in identifying BVA, and is sensitive to convergence and accommodation anomalies.