Howland H, Boothe R G, Kiorpes L
Science. 1982 Mar 12;215(4538):1409-11. doi: 10.1126/science.7063852.
In an experiment with ten macaque monkeys (Macaca nemestrina), a combination of photorefraction and corneal reflex photography was used to measure simultaneously the plane of focus and direction of gaze while they were presented with fixation targets. The monkeys ranged in age from 2 days to 10 weeks. Some of the infants that were less than 1 month old failed to change accommodation to targets at any distance, whereas others showed limited accommodative abilities. The magnitude of the accommodative response of infants older than 4 weeks appeared to be adultlike. Infant monkey's visual acuity improves dramatically after 4 weeks. These results, which show that the improvement in spatial resolution cannot be accounted for by increased accommodative accuracy, parallel those obtained from human infants where accommodative competence is attained by about 4 months of age.
在一项针对十只猕猴（食蟹猴）的实验中，采用了光折射和角膜反射摄影相结合的方法，在猕猴面对注视目标时同时测量其聚焦平面和注视方向。这些猴子的年龄从2天到10周不等。一些不到1个月大的幼猴在任何距离下都无法改变对目标的调节，而其他幼猴则表现出有限的调节能力。4周龄以上幼猴的调节反应幅度似乎与成年猴相似。幼猴的视力在4周后会显著提高。这些结果表明，空间分辨率的提高不能用调节精度的提高来解释，这与人类婴儿的情况相似，人类婴儿在大约4个月大时获得调节能力。
