科学与数学nature.com
近视大爆发
The myopia boom
2015 — 2019，它一次次回到首页
黑点是上首页（≥ 50 分）的那次投稿，空心点是没冲上去的投稿，点越大分数越高。
导读
《自然》新闻特稿梳理全球尤其是东亚近视率飙升的现象，并介绍研究认为童年期缺乏明亮户外光照会干扰多巴胺与昼夜节律、影响眼球正常生长，从而增加近视风险。文章也讨论这一趋势的公共卫生影响与防控思路。
为什么经久不衰：它把复杂的近视机制落到一个简单可操作的预防因素——增加户外明亮光照，同时涉及东亚的公共卫生问题，因此多年后仍值得读。
HN 评论精选
核心机制是户外强光通过多巴胺/昼夜节律影响眼轴生长；只要光照足够，近距离用眼并非主因。
我妻子正与中山大学团队合作撰写一篇关于此主题的综述论文。近视患病率上升非常惊人，尤其在亚洲人群中。文章很长，但核心观点是：幼儿期在超过1万勒克斯的强光下（大致相当于晴天待在阴影里）时间不足会增加近视风险。正常眼球生长需要多巴胺，其释放遵循昼夜节律，而这需要明亮日光暴露；缺少这种多巴胺循环可能使眼轴更长，导致屈光不正。预防近视所需的确切小时数难说，但即使学校每天多40分钟也有益，也有证据支持每天3小时以上。重要的是，只要孩子在强光下待够时间，近距离用眼（电脑、学习）多少似乎无关。我会考虑把书桌放在大窗边，课间去户外而不是室内。
sithu查看英文原文
My wife is co-authoring a review paper on this topic with the group from Zhongshan. The rise in myopia prevalence is really quite staggering, especially among asians. It's a long article, but the essential point is that insufficient time spent in bright light >10k lux (roughly corresponding to being in shade on a bright day) during early childhood increases the risk of developing myopia. Normal eye growth requires dopamine which is released in a circadian fashion, which requires exposure to bright/daylight. Absence of this dopamine cycle may cause the eyeball to be more elongated, leading to refractive errors. The precise number of hours needed to prevent myopia is difficult to say, but studies in schools with even 40-mins extra have shown benefit, and there's some evidence supporting 3+ hours/day. Importantly, it doesn't seem to matter how much close-focal work kids do, such as computer use/studying, as long as they spend sufficient time in bright light. I'd consider setting up a study desk in front of a large window, and taking breaks at school outdoors instead of inside.
文章核心结论可一句话概括，作者却铺陈过长。
简而言之，低光照会诱发近视；更具体地说，较高光照促使多巴胺释放，从而防止近视。不明白文章为什么花前2000词才说这一点。
richthegeek查看英文原文
The summary of this, which was surprisingly difficult to distill, is that low light levels induces myopia. Or more specifically, elevated light levels causes a dopamine release which prevents myopia. Not sure why the article needed to spend the first 2000 words not just saying that.
强调自然光谱、近用镜和休息，而非单纯提高人工照明。
不要一味提高人工光强度；问题很大程度在于光谱和分布。可以用视力表对比户外阴影与纯荧光灯下的视力差异。另外，负镜片会在眼内形成焦平面刺激、促使眼轴变长，这方面研究基本无争议；近距离工作时不应戴足额矫正远视力的眼镜，而应用降低度数的近用镜。还要休息：初期近视部分是睫状肌痉挛（可查假性近视或NITM），每三小时休息一小时、去户外看远处，别让睫状肌整天紧绷。
hnsighty查看英文原文
All right. What you don't want to do is increase artificial light intensity. A big part of the issue is the light spectrum and distribution of it. There is a pretty easy way to test / verify this, if you have an eye chart handy. Compare your acuity in outdoor, shaded light, to a solely fluorescent lit environment. Once you get to where you can barely make out the line, note the difference in acuity natural vs. artificial light. Also, the minus lens creates focal plane stimulus inside the eye that prompts axial elongation. Lots of studies on this subject, it's basically uncontested. What you really don't want to be doing is wear a lens that gives you sharp distance vision, while working up close. You want to have a specific reduced prescription for close-up, that just gives you correction to the distance you need. Breaks, also. Initial myopia is a ciliary (focusing muscle) spasm. Lots of studies there too, look for pseudo myopia or NITM (near induced transient myopia). Part of your current deficiency is ciliary, part is axial elongation. Take an hour break every three hours. Get outside. Focus at a distance. Your ciliary muscle isn't meant to be all tensed up (close-up use) all day. For more on the subject, take a look at www.frauenfeldclinic.com, those guys are fairly awesome.
质疑“不可逆视力丧失”的统计口径，提醒读者区分失明与视力下降。
文章说东亚大学年龄人群约五分之一有这种极端形式近视，其中一半预计会发展成不可逆视力丧失。这意味着东亚10%的大学年龄人群将发展不可逆视力丧失，听起来太可怕而不真实。我漏了什么？我把vision loss理解为失明，但也许它指视力下降？
xiaq查看英文原文
> About one-fifth of university-aged people in East Asia now have this extreme form of myopia, and half of them are expected to develop irreversible vision loss. Which means that 10% of university-aged people in East Asia are going to develop irreversible vision loss. This sounds too terrible to be true. Am I missing something here? I interpret vision loss as blindness, but maybe it is used to describe degraded vision instead?
历次讨论
同类还值得读
如果月球只有 1 像素：一个极其精确的太阳系模型（2014）
If the moon were only 1 pixel: A tediously accurate solar system model (2014)
一个网页版太阳系模型，以“如果月亮只有 1 像素”的真实比例呈现：你必须一路横向滚动，才能体会行星之间空旷到何等程度。
科学与数学上首页 7 次 · 2014–2025joshworth.com编辑精选沉浸式线性代数（2016）
Immersive Linear Algebra (2016)
《Immersive Linear Algebra》是一本完全免费、开放在线的线性代数“超文本教科书”，其最大特色是大量可交互的图形：读者可以直接拖动、操作图中的向量、矩阵和变换…
科学与数学上首页 5 次 · 2015–2024immersivemath.com编辑精选如何将贝果切成两个相连的半环（2009）
How to Slice a Bagel into Two Linked Halves (2009)
数学家 George Hart 的经典教程，演示如何用一刀把贝果切成两个相互扣住的环，并附上切割步骤与数学原理。
科学与数学上首页 5 次 · 2009–2022georgehart.com“犹太问题”：一组用于歧视的数学题
Jewish problems
一篇 arXiv 论文，整理并讨论苏联时期犹太学生在申请大学数学系时被问到的特殊数学难题：这些题往往有简单解法却极难想到，被用作面试中拒绝犹太考生的手段。
科学与数学上首页 5 次 · 2011–2021arxiv.org你的身体并非为长久而造：人类死亡率数据的一课
Your body wasn’t built to last: a lesson from human mortality rates
文章从人类死亡率随年龄变化的统计规律出发，解释身体并非为长久使用而设计：年轻时死亡风险较低，之后随年龄近似指数上升，像复杂系统在不断累积损伤。
科学与数学上首页 5 次 · 2009–2018gravityandlevity.wordpress.com