眼正负相对调节力比值变化与近视眼发病关系的研究

目的 选择同年龄段、同等学历的大学生测量不同屈光组眼正、负相对调节力及其比值等调节参数,分析其与近视眼的发病的关系.方法 同意被检查入校新生292人,平均年龄( 18.76±0.80)岁.正视组29人,低、中、高度近视组分别为118、82、37人；26人远视及屈光参差者被排除.被检者在电脑验光基础上,使用综合验光仪进行主觉验光,并测其调节幅度、正负相对调节力.结果 正视组正相对调节力(PRA)均值(-.4.87±1.47)D,低、中、高度近视组正相对调节力均值分别为(-2.36±1.21)D、(-2.92±1.40)D、(-2.86±1.81)D,不同近视组PRA比正视组均有显著降低(F=24.54,p=0.00)；正视组负相对调节力(NRA)均值(+2.09±0.46)D,低、中、高度近视组负相对调节力均值分别为(+1.99±0.51)D、(+1.95±0.45)D、(+1.99±0.47)D,各组比较差异无统计学意义(F=0.58,P=0.63)；正视组PRA/NRA的比值均值为2.35±0.51,低、中、高度近视组PRA/NRA的比值均值分别为1.21±0.66、1.53±0.76、1.49±0.95,不同近视组PRA/NRA的比值比正视组均有显著降低(F =19.06,P=0.00).结论 同年龄段、同等学历大学生近视组的正负相对调节力比值、正相对调节力明显低于正视组.近视眼的正负相对调节力比值及正相对调节力下降是近视眼发病的共同特征.

Relationship between PRA/NRA ratio and onset of myopia

Objective To investigate the difference of accommodation amplitude,PRA (positive relative accommodation),NRA (negative relative accommodation) and PRA/NRA ratio according to refractive status,and analyze the relationship between accommodation and the onset of myopia.Methods Two hundred and ninety-two randomly selected collage new entrants (average age 18.76± 0.80years old) were divided to 4 groups according to refractive status,including emmetropia group (29cases),low myopia group (118 cases),medium myopia group (82 cases) and high myopia group (37case).Twenty-six people and the ragged hyperopia refractive were excluded.Accommodation amplitude,PRA and NRA were measured with phoroptor.Results PRA for emmetropia group was -4.87+1.47D,in comparison to -2.36+ 1.21D for low myopia group,-2.92+ 1.40D for medium myopia group and -2.86± 1.81D for high myopia group,in comparison to three myopia groups,which was statistically significantly different (F =24.54,P ＜0.001).NRA of emmetropia was +2.09± 0.46D,and NRA of myopia was +1.99± 0.51D in low group,+1.95± 0.45D in medium group and +1.99± 0.47D in high group.in comparison to three myopia groups,Each comparative difference was statistically significant (F =0.58,P =0.63); The PRA/NRA ratio of emmetropia,low myopia group,medium myopia group and high myopia group was 2.35± 0.51,1.21± 0.66,1.53± 0.76 and 1.49+ 0.95,respectively.There was statistically significantly difference among emmetropia and myopia groups (F =19.06,P ＜0.001).Conclusions PRA and PRA/NRA ratio of myopia in collage new entrants is significantly less than emmetropia.The decrease of PRA may be common features of myopia onset.