Major Article
Stereoacuity norms for school-age children using the Frisby stereotest

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Background

The Frisby stereotest and the TNO test for stereoscopic vision are popular clinical tests for assessing stereoacuity: however, reference data for school-age children for the Frisby stereotest are limited. This study compared stereoacuity results of both tests in a large sample of typically developing school-age children.

Methods

Primary (elementary school grades 1-6) and post-primary (high school grades 7-11) students aged 6-16 years were recruited and assessed in schools. Stereoacuity thresholds were measured using the Frisby and TNO stereotests. Children with ocular pathology, anisometropia of ≥1.00 D, interocular difference of visual acuity ≥0.2 logMAR, or strabismus were excluded.

Results

A total of 212 children were recruited; data for 186 subjects were analyzed. Median Frisby stereoacuity scores were, for crossed disparity, 20 arcsec for primary and 10 arcsec for post-primary children and, for uncrossed disparity, 25 arcsec (primary) and 10 arcsec (post-primary). TNO stereoacuity was 60 arcsec for both age groups. For Frisby stereoacuity, scores of 85 arcsec (crossed) and 170 arcsec (uncrossed) or better were achieved by 95% of primary school children; scores of 85 arcsec (crossed and uncrossed) or better were achieved by 95% of post-primary subjects. A statistically significant difference in median stereoacuity scores was noted across age groups for the Frisby stereotest (crossed: z = 4.67, P < 0.0001; uncrossed: z = 4.67, P < 0.0001). No statistically significant difference in stereoacuity scores was noted with the TNO stereotest (z = 1.35, P = 0.18). A significant weak correlation was found between the Frisby and TNO stereotests (Frisby [crossed], r = 0.21 P < 0.005).

Conclusions

These data describe normative values for the Frisby stereotest for children aged 6-16 years. Participants recorded significantly better stereoacuity scores with the Frisby stereotest than the TNO stereotest. The Frisby stereotest values are weakly correlated with the TNO stereoacuity test.

Section snippets

Subjects and Methods

This study received ethical approval from the University of Ulster Research Ethics Committee and adhered to the tenets of the Declaration of Helsinki. As part of a wider study of vision, participants were recruited from primary (elementary grades 1-6) and post primary (high school grades 7-11) schools from one region of the United Kingdom across four age groups; 6-7 years, 9-10 years, 12-13 years, and 15-16 years. The schools represented a cross section of academic ability and socioeconomic

Results

A total of 212 participants were recruited. Of these, 3 were absent from school during data collection and were not tested, and 4 were excluded on the basis of parent-reported medical or ocular history. The remaining 205 participants successfully completed the Frisby and TNO stereotests. Data were omitted for an additional 19 children due to an interocular visual acuity difference of ≥0.2logMAR and/or anisometropia ≥1.00 D and/or strabismus; 186 study subjects (103 males [55%]) were analyzed.

Discussion

Reference data for the Frisby stereotest for school age children with good visual acuity and binocular vision are limited. This study reports median Frisby stereoacuity scores for primary school participants of 20 arcsec (crossed disparities) and 25 arcsec (uncrossed disparities), with 95% of children achieving scores of at least 85 arcsec (crossed) and 170 arcsec (uncrossed). Post-primary school participants achieved median stereoacuity scores of 10 arcsec (crossed and uncrossed disparities),

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  • Cited by (0)

    Funded by the Northern Ireland Health and Social Care Research and Development Office Northern Ireland (EAT/4197/09).

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