儿童的张力性调节、年龄与屈光不正

Zadnik K, Mutti D O, Kim H S, Jones L A, Qiu P H, Moeschberger M L

College of Optometry, The Ohio State University, Columbus 43210-1240, USA.

Invest Ophthalmol Vis Sci. 1999 May;40(6):1050-60.

PURPOSE

An association between tonic accommodation, the resting accommodative position of the eye in the absence of a visually compelling stimulus, and refractive error has been reported in adults and children. In general, myopes have the lowest (or least myopic) levels of tonic accommodation. The purpose in assessing tonic accommodation was to evaluate it as a predictor of onset of myopia.

METHODS

Tonic accommodation was measured in children enrolled in the Orinda Longitudinal Study of Myopia using an infrared autorefractor (model R-1; Canon, Lake Success, NY) while children viewed an empty lit field or a dark field with a fixation spot projected in Maxwellian view. Children aged 6 to 15 years were measured from 1991 through 1994 (n = 714, 766, 771, and 790 during the 4 years, successively). Autorefraction provided refractive error and tonic accommodation data, and videophakometry measured crystalline lens curvatures.

RESULTS

Comparison of the two methods for measuring tonic accommodation shows a significant effect of age across all years of testing, with the lit empty-field test condition yielding higher levels of tonic accommodation compared with the dark-field test condition in children aged 6 through 11 years. For data collected in 1994, mean (+/-SD) tonic accommodation values for the lit empty-field condition were significantly lower in myopes, intermediate in emmetropes, and highest in hyperopes (1.02 +/- 1.18 D, 1.92 +/- 1.59 D, and 2.25 +/- 1.78 D, respectively; Kruskal-Wallis test, P < 0.001; between-group testing shows each group is different from the other two). Age, refractive error, and Gullstrand lens power were significant terms in a multiple regression model of tonic accommodation (R2 = 0.18 for 1994 data). Lower levels of tonic accommodation for children entering the study in the first or third grades were not associated with an increased risk of the onset of myopia, whether measured in the lit empty-field test condition (relative risk = 0.90; 95% confidence interval = 0.75, 1.08), or the dark-field test condition (relative risk = 0.83; 95% confidence interval = 0.60, 1.14).

CONCLUSIONS

This is the first study to document an association between age and tonic accommodation. The known association between tonic accommodation and refractive error was confirmed and it was shown that an ocular component, Gullstrand lens power, also contributed to the tonic accommodation level. There does not seem to be an increased risk of onset of juvenile myopia associated with tonic accommodation.

目的

在成人和儿童中，已报道了张力性调节（即在没有视觉刺激的情况下眼睛的静息调节位置）与屈光不正之间的关联。一般来说，近视者的张力性调节水平最低（或近视程度最小）。评估张力性调节的目的是将其作为近视发病的预测指标进行评估。

方法

在参加奥林达近视纵向研究的儿童中，使用红外自动验光仪（R-1型；佳能公司，纽约州湖成功）测量张力性调节，同时儿童观看一个空的照明区域或一个暗场，暗场中有一个在麦克斯韦视野中投射的注视点。1991年至1994年对6至15岁的儿童进行了测量（4年中依次为n = 714、766、771和790）。自动验光提供屈光不正和张力性调节数据，视频晶状体测量法测量晶状体曲率。

结果

两种测量张力性调节方法的比较显示，在所有测试年份中年龄均有显著影响，与暗场测试条件相比，6至11岁儿童在空照明区域测试条件下的张力性调节水平更高。对于1994年收集的数据，近视者在空照明区域条件下的平均（±标准差）张力性调节值显著较低，正视者居中，远视者最高（分别为1.02±1.18 D、1.92±1.59 D和2.25±1.78 D；Kruskal-Wallis检验，P<0.001；组间测试表明每组与其他两组均不同）。在张力性调节的多元回归模型中，年龄、屈光不正和古尔斯特兰德晶状体屈光度是显著因素（1994年数据的R2 = 0.18）。无论是在空照明区域测试条件下（相对风险 = 0.90；95%置信区间 = 0.75，1.08）还是在暗场测试条件下（相对风险 = 0.83；95%置信区间 = 0.60，1.14），一年级或三年级入学儿童较低的张力性调节水平与近视发病风险增加无关。