Longitudinal Rehabilitation of Binocular Function in Adolescent Intermittent Exotropia After Successful Corrective Surgery

PurposeTo study the longitudinal rehabilitation of binocular visual function in adolescent intermittent exotropia (IXT) after successful surgery and compare the results with those of a normal population. The role of binocular function in ocular alignment stability was also evaluated postoperatively.MethodsIn this prospective study, 30 adolescents with IXT successfully corrected after 1 month were followed for 12 months, and 30 children with normal vision were enrolled as controls. Stereopsis, the fusional vergence amplitude, sensory fusion, and accommodative flexibility were measured to assess binocular function at baseline and 6 and 12 months postoperatively. The controls were tested once when they were enrolled in the study.ResultsThe deviation was −32.00 ± 8.60 prism diopters (PD) at distance fixation and −36.0 ± 9.10 PD at near fixation preoperatively with an average correction of 28.53 ± 3.79 PD and 30.67 ± 1.34 PD at 1 month postoperatively. Distance stereoacuity and near stereoacuity improved from 1 to 12 months postoperatively (p = 0.025 and p = 0.041, respectively). Compared with the controls, the fusional convergence reserve at distance (p = 0.025) and near (p = 0.033) fixations and fusion reserve ratio at distance (p = 0.000) and near (p = 0.000) fixations remained subnormal, whereas sensory fusion (p = 0.237), distance stereopsis (p = 0.120), and the fusional divergence amplitude at a distance (p = 0.168) were normal. However, no significant correlations were found between binocular functions at 1 month postoperatively and the postoperative drift.ConclusionBinocular function significantly improved from before to after successful corrective surgery and continued to improve from 1 to 12 months postoperatively in adolescents with IXT. No significant correlations were found between binocular functions at 1 month postoperatively and ocular alignment stability.

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

Purpose: To investigate the relationship between binocular function with gender, ages, and spherical equivalent (SE) .Methods: This observational study enrolled 243 healthy, non-strabismic adults, including 94 men and 149 women aged from 20 to 59 years. The subjects were divided into three groups according to SE: myopic group, emmetropic group and hyperopic group. The subjects were also divided into four groups according to age: 20-29 years group, 30-39 years group, 40-49 years group, and 50-59 years group. The binocular vision function was measured with a synoptophore, including subjective angle (SA), divergence, convergence and fusional vergence range (FVR). Results: The mean values of SA, divergence, convergence and range of fusion for the whole sample group were 3.33±0.16°, 9.72±0.26°, 19.34±0.54°, and 29.06±0.62°, respectively. The mean values of SA and divergence in myopic group were significantly larger than the emmetropic group (both p<0.05). SE, SA, divergence and FVR were significantly different among age groups (all p<0.05). Besides, linear regression analysis showed SE was correlated with SA and divergence (p=0.007, p=0.003). Age was correlated with SE, SA, divergence and FVR (p<0.001, p<0.001, p=0.005, p=0.002, respectively). In addition, the proportion of SA being in comfort zone (defined as the value of SA located in the middle 1/3 area of FVR) in age groups were statistically different. (χ2=8.283, p=0.041)Conclusion: Both SA and motor fusion are associated with age and SE in normal adult population.

Prevalence and Risk Factors of Myopia in Spain

Objective. To analyse the prevalence of myopia among a sample of more than 6000 children in Spain as well as to determine the impact of risk factors in its progression. Methodology. A total of 6,152 children aged from 5 to 7 were examined. The participants underwent an eye examination that included visual acuity, refraction without cycloplegia, and tests of accommodative and binocular function. In addition, a questionnaire regarding their lifestyle, family history, and geographical data was carried out. Finally, data were analysed using the SPSS version 25 program. Results. The prevalence of myopia in the sample of children studied has increased from 17% in 2016 to 20% in 2017. Likewise, the number of children with high myopia has also increased, from 1.7% in 2016 to 3.6% in 2017. 43.3% of the participants spent more than 3 hours a day doing near activities, and 48.9% of this group spent more than 50% of this time using electronic devices. In addition, only 9.7% spent more than 2.5 hours outdoors each day. Conclusion. Myopia prevalence appears to be increasing in Spain. Lifestyle factors appear to be increasing the risk of myopia.