If you wear contact lenses, your doctor probably told you not to wear them for too long,
如果你佩戴隐形眼镜，你的医生可能会告诉隐形不能戴太久，
and there are a lot of good reasons for that.
其中原因有很多rT7)7A^ywQCSpuX。
A student in England for instance, tried to take her contacts out with dry eyes after leaving them in for 10 hours
比如一名英国学生，她在佩带十小时后取出隐形眼镜，出现眼睛干涩的情况
and ended up ripping off part of her cornea.
最终她的部分角膜被摘除I8~!e&o,.g。
Another student in Taiwan... why is it always students?...
另一名台湾的学生...怎么总是学生呢？...
left contacts in for six months which created the perfect environment for bacteria and amoebas to burrow into her eye.
六个月不取隐形眼镜，这就为细菌和变形虫钻入她的眼中提供了完美的环境np6v=K|+sz。
Just got to get the nice outside-of-your-eyes lenses. These are good.
就带漂亮的框架眼镜就好了]_%@1Zq!M8%0+#x|s。
So even though contacts are generally safe to wear,
所以即使佩带隐形眼镜通常是安全的，
they do come with lots of biological risks if you don't follow your doctor's instructions.
但如果没有遵照医嘱，还是存在许多生物性风险的Mc5g1=oue^&be^uohZ。
Contact lenses work like glasses do: bending light, so it focuses properly on the photoreceptors at the back of your eye,
隐形和镜片工作原理相同：折射光，将光适当地聚集在你的眼睛后边的感官器上，
which send information to your brain. Contacts sit right on top of your cornea.
并向你的大脑传递信息zeXKDlyP&ID^LXytC。隐形正佩带在你角膜的顶部FMFv]gw8U&4I,DkFK+M。
That's the outermost layer of transparent tissue that helps focus light entering your eye
这是透明组织的最外层，透明组织能够帮助聚集进入你眼中的光
and protects everything else from things like dust, germs and UV radiation.
并保护眼睛不受灰层、细菌以及紫外线的伤害IM5sy_,H(Ud.WLI#L4。
There are two main dangers to leaving your contacts in for too long.
长时间佩带隐形存在两个主要危险)B50bW]~)[9y!。
For one the cells on your cornea are alive and need to stay wet, so you have a built-in moisturizing system.
第一，你角膜的细胞是活的，它们需要保持湿润，所以你有一个内置保湿系统cRA6-nI6Atw%!iz628。
You have glands that coat your eyes with tears,
你还有腺体，能够用眼泪盖住你的眼睛，
which are a mix of water and things like oils, nutrients, immune cells and mucus related proteins,
眼泪是水和油、营养盐、免疫细胞以及黏液相关的蛋白质的混合，
but contacts can interfere with this tear layer by soaking up moisture or keeping it from getting to your eyes cells.
但隐形眼镜会吸收水分或阻止水分进入到眼细胞中从而干扰了泪层L=2Z=eMWMTC。
Dry eyes can get really irritating, and could lead to corneal damage.
干涩的眼睛变得非常刺激，可能会导致角膜损害gq)y3wiWBQd|s&^WrC.。
And second, leaving contacts in for too long can increase your risk of getting an eye infection from some nasty microorganisms.
第二，长时间佩带隐形会增加眼镜感染有害微生物的风险!L!GDetw*u!jU。
Contacts that have been sitting on your cornea for a while can cause physical scratches that damage your cells
隐形眼镜长时间附在你的角膜上可能会导致物理性划痕从而损伤你的细胞
or reduce the flow of oxygen that cells need to survive,
或减少细胞生存所需的氧气流，

and then if you didn't wash your contacts well enough with a disinfecting solution,
如果你没有用足量的消毒溶液清洗隐形，
any bacteria, viruses, fungi or parasites hanging around can get into the damaged cornea tissue.
那么周围任何的细菌、病毒、真菌或寄生虫都会钻进受损的角膜组织中|Vc=0xh2XGaLdDbwo,。
With enough time, these pathogens can multiply and cause a full-blown cornea infection, generally called keratitis.
只要时间足够，这些病原体可以繁殖并引发全面角膜感染，通常被称为角膜炎f=1[zWf08_。
Keratitis usually starts with inflammation and pain as your body tries to fight it off,
角膜炎起于炎症和疼痛，身体会进行抵抗，
but it can get really bad without treatment.
但如果没有进行治疗，也会导致严重后果)!iTMw@vo]j!k,。
If your cornea gets too damaged, you can even lose your eyesight.
如果你的角膜受损严重，甚至会导致失明;1AoqWcQfGbtk0[.。
But even if you are really good about following instructions,
但即使你真的很好地遵照医嘱，
scientists have discovered that using contacts regularly for long periods of time,
科学家发现长时间经常性使用隐形
like more than five years can affect your eyes too.
比如五年多，也会对眼睛造成影响ft.O@VN#Bq[t6。
Several studies have found that long-term contact use can reduce the thickness of your cornea.
一些研究发现长期使用隐形会降低角膜的厚度+^k_sMo2DzG。
It's not necessarily bad,
这并不一定是坏事，
but enough of a shape change could affect your vision or prevent you from getting laser eye surgery safely.
但是角膜形状被改变到一定程度还是会影响你的视力或是让你无法安全的进行激光眼科手术2T(|Qp&aOVz。
We're not exactly sure why this thinning happens,
我们不确定为什么隐形会降低角膜厚度，
but it might have something to do with the reduced amounts of oxygen affecting how the tissue grows.
但这可能和影响组织生长的氧含量的减少有关zkh=+#lxM9,~^=TDOF#_。
So you might wear contacts for lots of reasons like convenience, appearance or to have closer to normal vision,
可能你还是会出于某些原因而佩带隐形，比如，为了方便、好看或是看得清楚，
even though leaving them in for too long can get really bad,
即使长时间佩带真的对眼睛不好，
the risks are generally small as long as you are careful to do what your doctor tells you to do.
但如果你仔细地遵照医嘱，其风险通常会较小AST2c#vC2GGXU[。
Thanks to our Patreon patrons for asking,
感谢Patreon的观众提问，
and if you want to learn more about vision science,
如果你想了解更多关于视觉科学的知识，
you could check out our video that explains how glasses don't really ruin your eyesight.
你可以点击观看解释眼镜不会真的有损视力的视频OIZcIj6M0x。