The aim of this study is to observe the binocular visual dysfunction in myopic anisometropia adolescents.

This was a cross-sectional study. A total of 142 patients (284 eyes) with myopic anisometropia who were seen in the Ophthalmology Department of Chongqing University Jiangjin Hospital from December 2022 to November 2023 were selected. Among them, 70 cases (140 eyes) were male, 72 cases (144 eyes) were female, with a mean age of (14.9±2.2) years (ranging from 10 to 18 years). Anisometropia was divided into low anisometropia and high anisometropia groups based on the change of spherical equivalent between two eyes values. According to the degree of myopia, they were divided into low myopia group, moderate myopia group, and high myopia group. The refractive power, adjustment amplitude, convergence near point, far and near distance eye positions, far and near distance fusion and dispersion function, and stereoscopic vision function between individuals with binocular visual impairment and normal individuals with myopic anisometropia were compared. Quantitative data such as refractive power, adjustment amplitude, convergence near point, far and near distance eye position, far and near distance fusion and dispersion function, and stereoscopic function after Kolmogorov-Smirnov normality testing conformed non normal distributions and were described by the median and interquartile range[M(IQR)]. The correlation between binocular visual function and anisometropia was used by Spearman rank correlation analysis. The types and prevalence of binocular visual impairment were described using case numbers and percentages, and compared by chi-square tests. The influencing factors of binocular vision function was performed by multiple logistic regression analysis.

The average refractive error, stereoscopic vision, convergence of near points, amplitude of adjustment, sensitivity of adjustment, distance and near distance deviation in adolescents with myopic anisometropia were -1.50 (0.85) D, 40 (48.75) " , 5.25 (2.22) cm, 11.10 (2.85) D, 12 (7) cmp, 0 (2)^△, and 0 (3)^△, respectively. The distance base inward rupture point and recovery point in adolescents with myopic anisometropia were 6 (2)^△ and 4 (2)^△, respectively. The distance base outward blurred point, rupture point, and recovery point in adolescents with myopic anisometropia were 6 (4)^△, 18 (8)^△ and 14(8)^Δ, respectively. The blurry points, rupture points, and recovery points with the base facing inward at close range in adolescents with myopic anisometropia were 8 (4)^Δ, 14 (5.5)^Δ, and 12 (6)^Δ, respectively. The blurry points, rupture points, and recovery points with the base facing outward at close range in adolescents with myopic anisometropia were 14 (8)^Δ, 25 (10)^Δ, and 20 (9)^Δ, respectively. Among of 142 cases (284 eyes), there were 117 cases (234 eyes) in the low degree anisometropia group and 25 cases (50 eyes) in the highly anisometropic group, accouting for 82.39% and 17.61%. There were a total of 70 cases (140 eyes) of binocular visual impairment, accounting for 49.29%. Among them, there were 23 cases (46 eyes), 23 cases (46 eyes) and 18 cases (36eyes) with abnormal regulation function, abnormal collective function, and abnormal combination of two or more functions, accounting for 16.20%, 16.20%, and 12.66%, respectively. According to Spearman correlation analysis, there was a positive correlation between anisometropia and close range esotropia, with statistical significance (r=0.192, P<0.05). There were 38 males (76 eyes) and 32 females (64 eyes) with binocular visual impairment, accounting for 54.29% and 44.44%, respectively; 32 males (64 eyes) and 40 females (80 eyes) with normal binocular vision function, accounting for 44.44% and 55.55%, respectively. The difference was not statistically significant between two groups (χ²=1.375, P>0.05). There were 20 cases (40 eyes) and 50 cases (100 eyes) of high anisometropia and low anisometropia with binocular visual impairment , accounting for 80.00% and 42.73%, respectively. There were 5 cases (10 eyes) and 67 cases (134 eyes) with normal binocular visual function in high degree anisometropia and low degree anisometropia, accounting for 20.00% and 57.27%, respectively. The difference was statistically significant (χ²=11.444, P<0.05). There were 35 cases (70 eyes), 70 cases (140 eyes), and 37 cases (74 eyes) in the low-grade myopia group, moderate myopia group, and high myopia group. There were 21 cases (42 eyes), 34 cases (68 eyes), and 15 cases (30 eyes) with low, medium, and high myopic binocular visual impairment, accounting for 60.00%, 48.57%, and 40.54%, respectively. There were 14 cases (28 eyes), 36 cases (72 eyes), and 22 cases (44 eyes) with normal binocular vision function in the low, medium, and high myopia group, accounting for 40.00%, 51.43%, and 59.46%, respectively. The difference was not statistically significant between them (χ²=2.754, P>0.05). After multiple logistic regression analysis, the degree of anisometropia was a statistically significant risk factor for binocular vision function (OR=6.69, 95%CI: 2.25 to 19.88; P<0.05). The degree of myopia was a protective factor for binocular visual function, with statistical significance (OR=0.56, 95%CI: 0.34 to 0.93; P<0.05).

The incidence of binocular visual dysfunction is higher in adolescents with myopic anisometropia, and with the increase of anisometropia, the close range deviation increases. Patients with low myopia and high anisometropia are more prone to binocular visual dysfunction, and the degree of anisometropia is an important influencing factor on binocular visual function.