Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13–18 years

Abstract

Aim:The aim of this study was to explore possible associations between stereoacuity and refractive, accommodative and vergence anomalies. Methods:The study design was cross-sectional and comprised data from 1056 high school children aged between 13 and 18 years; mean age and standard deviation were 15.89 ± 1.58 years. Using a multi-stage random cluster sampling, participants were selected from 13 high schools out of a sample frame of 60 schools in the municipality concerned. In the final sample, 403 (38%) were males and 653 (62%) females. Refractive errors, heterophoria, near point of convergence, fusional vergences and accommodative functions (amplitude, facility, response and relative) were evaluated. Stereoacuity was evaluated using the Randot stereotest and recorded in seconds of arc where reduced stereoacuity was defined as worse than 40 s arc.Results: Overall, the mean stereoacuities (in seconds of arc) of the children with anomalies were the following: those with refractive errors (52.6 ± 36.9), with accommodative anomalies (53.1 ± 34.1) and with vergence anomalies (48.29 ± 31.1). The mean stereoacuity of those with vergence anomalies was significantly better than that of those with either refractive errors or accommodative anomalies (p = 0.02). In the refractive error category, only anisometropia had significantly reduced mean stereoacuity compared to emmetropia (Mann-Whitney U: p = 0.01). The mean stereoacuity of cases of accommodative anomalies was significantly reduced compared to those without such anomalies (Mann-Whitney U: p = 0.01). Similarly, the mean stereoacuity of cases with vergence anomalies was significantly reduced compared to those without vergence anomalies (p = 0.02). Conclusion:Refractive errors, accommodative or vergence anomalies are more likely to have reduced mean stereoacuity than cases without such anomalies. Refractive errors or accommodative anomalies had significantly more reduced stereoacuity than vergence anomalies. These findings suggest that the Randot stereotest could be used to identify those with such anomalies, and this study extends knowledge regarding the possible use of stereoacuity as a useful tool to screen for binocular anomalies. Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13-18 yearsRead online:Scan this QR code with your smart phone or mobile device to read online.

The effect of induced blur monocularly and binocularly on stereoacuity

“…Poor amplitudes of accommodation could have contributed to their study findings because accommodation dysfunctions were also found to impact on stereoacuities. 19,20 Even though in this study significant associations (p = 0.00) between induced blur monocularly and binocularly using the 2 D and 3 D lenses were found, their correlation was found to be weak with r = 0.45 and 0.22, respectively. Contrary to the findings of the study conducted by Yang et al, 21 which found a significant correlation between different groups of spherical errors and stereoacuity measured and thus concluded that high hyperopia (> 3 D) severely reduced stereoacuity.…”

“…However, there are still ongoing debates related to reduced vision monocularly or binocularly and their severity on stereoacuity. 17 Wajuihian and Hasraj, 18,19 in their study investigated the relationship between stereoacuity, refractive status, accommodative and vergence anomalies of South African school children with a mean age 15.89 ± 1.58 years and concluded that accommodative and convergence dysfunctions affected stereoacuity. Furthermore, participants with anisometropia were found to have significantly reduced mean stereoacuities compared to those with emmetropia.…”

“…As a result, they suggested that the Randot ® Stereo Test (RST) could be used to identify those with REs, accommodative or vergence anomalies and further supported stereoacuity measurements as a useful tool to screen for binocular anomalies. 18,19 However, the aim of this study was to determine the severity and amount of stereoacuity of induced blur monocularly and binocularly using the RST at near (40 cm).…”

Assessment of stereoacuity (3D vision) using TNO random dot stereo acuity chart in medical undergraduate students: A cross-sectional study

“…The factors that cause inappropriate development of stereopsis are many; one notable cause being uncorrected refractive errors. 8,11,12 All types of refractive errors adversely affect stereopsis by inducing visual blur, resulting in decreased binocular function with low sensory fusion. 8,13 In this study, subnormal stereopsis was found more in simple myopia, followed by compound myopic astigmatism and amblyopia.…”

Effects of Refractive Errors and Age on Binocular Function in Normal Adult Population

“…Convergence insu ciency was more likely to occur in patients with a lower degree of myopia, while divergence insu ciency was more likely to occur in patients with a higher degree of myopia [7]. Another clinical study revealed that high school children (aged between 13 and 18 years) with refractive errors, accommodative or vergence anomalies were more likely to have reduced mean stereoacuity than cases without such anomalies [8]. Kirwan and O'keefe [9] believed that stereopsis was related to anisometropia and that every 0.25 D difference of binocular refraction can cause a 0.5% difference in the retinal image.…”