Dominant Eye And Binocular Vision Function In Myopic Anisometropia

PurposeTo study the relationship between dominant eye and degree of myopia, analyze accommodation function of dominant and nondominant eye, and analyze binocular vision function in myopic anisometropia in order to explore the reason for the cause, development and measure for improvement in myopic anisometropia. MethodsCross-sectional study. 59 myopic anisometropic patients were included in the study, aged between eight and thirty-five. Patients were divided into two groups according to the degree of anisometropic, including group A(difference less than 2.50 D in two eyes) and group B(difference more than 2.50D). According to the age patients were divided into two groups, including group C(age between 8 and 18) and group D(age between 18 and 35).,Monocular and binocular PRA, NRA, amplitude of accommodation, and accommodative facility were all measured using phoropter. Dominant eye was identified by the means of hole shaped by two hands. Amplitude of accommodation, accommodation response time, accommodative facility were measured in monocular and binocular. NPC was measured by the method of push-to-near. Ocular position, fusion vergence, AC/A were measured by Von Graefe. The data of accommodation analyzed by a nonparametric test, t-test and correlation analysis. Chi-square test was used to compare the significance of differences among the distributions of binocular vision function of different groups. Results1. Twenty six patients were included in group A. Dominant eye was right in 22 patients(84.5%). The mean diopter were-4.01 ± 1.96 D and-3.19 ± 1.80 D in dominant and non-dominant eye, respectively. The mean anisometropia was 1.76±0.21 D. The refraction was significantly different in dominant and non-dominant eyes(z=-2.37,P<0.05). 33 patients were included in group B. Dominant eye was right in 21 patients(63.6%). The mean diopter were-3.90±2.84 D and-3.47±2.20 D in dominant and non-dominant eye, respectively(z=-2.37, P<0.05). The mean anisometropia was 3.40±0.81 D.2.The mean PRA was-2.68 ± 1.44 D and-3.29 ± 1.31 D in dominant and non-dominant eyes in group A(z=-2.27,P<0.05). The mean PRA was-3.14±1.84 D and-4.10±1.59 D in dominant and non-dominant eyes in group B(z=-3.544,P<0.05). The mean absolute PRA /NRA value was 1.15±0.58 and 1.36±0.52 in dominant and non-dominant eyes in group A(z=-1.89,P>0.05). The mean absolute PRA /NRA value was 1.34±1.57 and 1.74±0.62 in dominant and non-dominant eyes in group B(z=-3.03,P<0.05). The mean accommodation response time was +0.51±0.34 D and +0.36±0.43 in dominant and non-dominant eyes in group A(z=-1.80,P>0.05). The mean accommodation response time was +0.54 ± 0.33 D and +0.33 ± 0.25 D in dominant and non-dominant eyes in group B,respectively(z=-2.37,P<0.05).3. Impairment of binocular visual function was more serious in Group B than Group A. Ocular position in near distance was abnormal in 11 patients(57.69%) and 24 patients(72.73%) in Group A and Group B, respectively(χ2=5.58,P<0.05). AC/A in 8 patients(30.77%)was lower, 2 patients(7.69%) was higher than normal in Group A. AC/A in 23 patients(69.70%) was lower, 1 patients(3.03%) was higher than normal in Group B. AC/A was significant different in two groups(χ2=6.99,P<0.01). Visual function in far distance was abnormal in 7 patients(26.92%) and 15 patients(45.45%) in Group A and Group B, respectively(χ2=2.14,P>0.05). Visual function in near distance was abnormal in 9 patients(34.62%) and 20 patients(60.61%) in Group A and Group B, respectively(χ2=3.93,P<0.05). Mean stereopsis was 71.92±73.92 ", 5 patients(19.23%) was abnormal in Group A. Mean stereopsis was 130.91±119.83", 15 patients(45.45%) was abnormal in Group B. The presence was significantly different in two groups, respectively(χ2=4.49,P<0.05) Conclusion1.Refraction in dominant eyes in patients with lower myopic anisometropia was higher than non-dominant eyes.2. PRA and PRA/NRA in dominant eyes were lower than non-dominant eyes and dominant eyes were accommodative lag in different degree anisometropic patients.3. The higher myopic anisometropia, the more serious impairment of binocular visual function.