Accommodation, accommodative convergence, and response AC/A ratios before and at the onset of myopia in children
Accommodation, accommodative convergence, and response AC/A ratios before and at the onset of myopia in children
复制标题
DOI：
10.1097/01.opx.0000159363.07082.7d
复制
发表时间：
2005-04-01
影响因子：
1.4
通讯作者：
Held, R
中科院分区：
文献类型：
--
作者：
Gwiazda, J;Thorn, F;Held, R
目的。本研究的目的是调查儿童近视发生前和发生时的调节、调节收敛和AC/A比率。方法：研究方法。对80名6~18岁(平均初诊年龄11.1岁)的6~18岁儿童进行了3年的屈光不正、调节和屈光参差测量，其中26名近视患者近视度数超过-0.50D，54名儿童保持正视状态(-0.25~+0.75D)。采用非睫状肌麻痹距离检影测量屈光度。使用佳能R-1开放视场自动验光仪和电动Risley棱镜和Maddox杆，对4.0RN和0.33m处的Letter目标采取相应的调节和闪光措施。调节和屈光不正测量用于计算反应性AC/A比率。结果。与保持正视的儿童相比，近视儿童在近视发病前1年和2年，以及发病后1年和1年后的AC/A比值均高于正视儿童(t‘s=-2.97~-4.04，p<；0.01)。近视儿童的AC/A比率明显较高，是调节能力显著降低的结果。调节性收敛仅在近视眼发病时显著增加。结论。这些发现表明，近视发病前发现的异常眼球运动因素可能通过在儿童从事近视任务时产生远视性视网膜离焦而导致近视形成。
Purpose. The purpose of this study was to investigate accommodation, accommodative convergence, and AC/A ratios before and at the onset of myopia in children. Methods. Refractive error, accommodation, and phorias were measured annually over a period of 3 years in 80 6- to 1 8-year-old children (mean age at first visit = 11.1 years), including 26 who acquired myopia of at least -0.50 D and 54 who remained emmetropic (-0.25 to + 0.75 D). Refraction was measured by noncycloplegic distance retinoscopy. Concomitant measures of accommodation and phorias were taken for letter targets at 4.0 rn and 0.33 m using the Canon R-1 open field-of-view autorefractor with an attached motorized Risley prism and Maddox rod. The accommodation and phoria measurements were used to calculate response AC/A ratios. Results. Compared with children who remained emmetropic, those who became myopic had elevated response AC/A ratios at I and 2 years before the onset of myopia, in addition to at onset and 1 year later (t's = -2.97 to -4.04, p < 0.01 at all times). The significantly higher AC/A ratios in the children who became myopic are a result of significantly reduced accommodation. Accommodative convergence was significantly greater in myopes only at onset. Conclusions. These findings suggest that the abnormal oculomotor factors found before the onset of myopia may contribute to myopigenesis by producing hyperopic retinal defocus when a child is engaged in near-viewing tasks.