【摘要】 目的用强度矢量法研究小儿静态屈光不正,比较视网膜检影测出的总合散光与角膜曲率计测出的角膜散光的关系。方法分别用视网膜检影与角膜曲率计对152只眼(76人)行静态屈光检查。将屈光不正结果表达成三维直角屈光度坐标上的点。直角屈光度坐标上的每一点坐标(x,y,z)对应于屈光处方的三个分解成分:等效球镜成分、Jackson交叉柱镜J0成分在90°和180°轴位上、和Jackson交叉柱镜J45成分在45°和135°轴位上。结果总合散光的绝对值(TA)与角膜散光的绝对值(CA)呈线形关系。相关系数为0.876,相关系数的统计意义检验(t检验)P值<0.001。直线回归方程为(TA)=0.9759(CA)-0.3743。总合散光交叉柱镜J0成分(RJ0)与角膜散光的交叉柱镜J0成分(CJ0)呈线形关系。相关系数为0.878,相关系数的统计意义检验(t检验)P值<0.001。直线回归方程为RJ0=1.0091CJ0-0.2461。总合散光交叉柱镜J45成分(RJ45)与角膜散光的交叉柱镜J45成分(CJ45)呈线形关系。相关系数为0.570,相关系数的统计意义检验(t检验)P值<0.001。直线回归方程为RJ45=0.559CJ45+0.0024。视网膜检影与角膜曲率计在配对t检验中,总合散光的绝对值[TA]与角膜散光的绝对值的差值均值和标准差为(-0.4290±0.6572,P<0.001),Jackson交叉柱镜J0成分的差值均值和标准差为(-0.2362±0.3318,P<0.001),Jackson交叉柱镜J45成分的差值均值和标准差为(-2.3E-0.3±0.2695,P=0.917)。剩余散光为预测的总合散光与实际的总合散光之差值。61.8%的剩余散光在0.25至0.5D,34.2%的剩余散光在0.5至0.75D,2.6%的剩余散光在0.75至1.0D。结论临床上,角膜曲率计测出的角膜散光可以预测总合散光。95%剩余散光小于0.75D,因此,有一定的实用价值。更多还原

【Abstract】 Objective To apply vector approach to study the relation of total astigmatism and corneal astigmatism. Methods 152 cycloplegic children eyes(76 people) were performed retinoscopies and keratometers. Refractive errors were expressed as power vectors suitable for plotting as points in a 3-dimensional dioptric space. The 3 cartesian coordinates(x,y,z) of each power vector correspond to the powers of 3 lenses that, in combination, fulfill a refractive prescription: a spherical equivalent power (SEP), and a Jacson crossed cylinder of power so with axes at 90 degrees and 180 dgrees, a Jackson crossed cylinder of power J45 with axes at 45 degrees and 135 degrees. Results There is a strong linear relationship between the absolute value of total astigmatism and that of corneal astigmatism. The correlation coefficient is 0.876(P<0.001). The regression equation is TA=0.9759CA-0.3743. There is a strong linear relationship between the refractive error J0 of total astigmatism and that of corneal astigmatism. The correlation coefficient is 0.878(P<0.001). The regression equation is RJ0=1.0091CJ0-0.2461. There is a strong linear relationship between the refractive error J45 of total astigmatism and that of corneal astigmatism. The correlation coefficient is 0.570(P<0.001). The regression equation is RJ45=0.559CJ45+ 0.0024. The paired differences and standard deviation of the absolute value be- tween total astigmatism and corneal astigmatism in the paired samplest test is (-0.4290 ± 0.6572,P<0.001). The paired differences and standard deviation of the J0 between total astigmatism and corneal astigmatism in the paired samples’t test is (-2.3E03 ± 0.2695,P=0.917).The residual refractive error cylinder power (Cres) is thedifference between predictions and obtained values. 61.8% of Cres is between 0.25 and 0.5D, 34.2% of Cres is between 0.5 and 0.75D, 2.6%of Cres is between 0.75 and 1.0D. Conclusions It’s practical that corneal astigma- tism measured by keratometer could be used to predict total astigmatism because 95% of Cres is within 0.75D.更多还原