Tran Nina, Chiu Sara, Tian Yibin, Wildsoet Christine F
School of Optometry, University of California, Berkeley, CA 94720-2020, USA.
Vision Res. 2008 Jul;48(15):1655-62. doi: 10.1016/j.visres.2008.03.022. Epub 2008 Jun 3.
This study sought further insight into the stimulus dependence of form deprivation myopia, a common response to retinal image degradation in young animals.
Each of 4 Bangerter diffusing filters (0.6, 0.1, <0.1, and LP (light perception only)) combined with clear plano lenses, as well as plano lenses alone, were fitted monocularly to 4-day-old chicks. Axial ocular dimensions and refractive errors were monitored over a 14-day treatment period, using high frequency A-scan ultrasonography and an autorefractor, respectively.
Only the <0.1 and LP filters induced significant form deprivation myopia; these filters induced similarly large myopic shifts in refractive error (mean interocular differences+/-SEM: -9.92+/-1.99, -7.26+/-1.60 D, respectively), coupled to significant increases in both vitreous chamber depths and optical axial lengths (p<0.001). The other 3 groups showed comparable, small changes in their ocular dimensions (p>0.05), and only small myopic shifts in refraction (<3.00 D). The myopia-inducing filters eliminated mid-and-high spatial frequency information.
Our results are consistent with emmetropization being tuned to mid-spatial frequencies. They also imply that form deprivation is not a graded phenomenon.
本研究旨在进一步深入了解形觉剥夺性近视的刺激依赖性，这是幼龄动物对视网膜图像退化的一种常见反应。
将4种邦加特漫射滤光片（0.6、0.1、<0.1以及仅能感知光的LP滤光片）分别与平光镜片组合，再加上单独的平光镜片，单眼佩戴在4日龄雏鸡上。在为期14天的治疗期间，分别使用高频A超超声检查和自动验光仪监测眼轴尺寸和屈光不正情况。
只有<0.1和LP滤光片会引起显著的形觉剥夺性近视；这些滤光片导致的屈光不正近视性偏移幅度相似（平均眼间差异±标准误：分别为-9.92±1.99、-7.26±1.60 D），同时玻璃体腔深度和眼轴长度均显著增加（p<0.001）。其他3组的眼尺寸变化相当小（p>0.05），屈光不正只有小幅度的近视性偏移（<3.00 D）。导致近视的滤光片消除了中高频空间信息。
我们的结果与正视化过程针对中空间频率进行调节相一致。它们还表明形觉剥夺不是一种渐变现象。
