为什么你的眼睛会红

What's causing those red eyes?
什么导致了眼睛充血？

If the eyes are the mirrors of the soul, bloodshot eyes are the mirrors of your health, letting you know that something's going on either with your eyes themselves or in another part of your body. But because so many conditions can cause one or both of your eyes to take on a reddish hue, it's not always easy to figure out what's causing the redness-and what you should do about it.
如果眼睛是心灵的窗户，那么充满血丝的眼睛则是健康的镜子，让你知道要么是你的眼睛出了问题，要么就是你的身体出了问题。但因为很多情况都能导致你的眼睛（一只或两只）呈现红色的血丝，所以想要搞清楚究竟是什么原因导致眼睛充血、以及如何应对并非易事。

"Usually the eyes turn red because the blood vessels on the surface of the eye get dilated or inflamed," explains Jessica Lee, MD, assistant professor of vitreoretinal surgery, department of ophthalmology at the New York Eye and Ear Infirmary of Mount Sinai. "And there are a multitude of reasons that can happen."
"通常情况下，眼睛充血是因为眼睛表面的血管扩张或发炎引起的，"西奈山纽约眼耳专科医院眼科玻璃体视网膜外科的助理教授杰西卡·李医学博士解释道。"导致眼睛充血的原因还有很多。"

Some of these reasons are simple and have an easy fix, while others are more serious; red, inflamed, and/or itchy eyes could be the first sign of a condition that may have a real impact on your vision. We asked Dr. Lee to explain all the things that could cause red eyes, so you can better determine why you're sporting the bloodshot look and how to treat it.
有些原因很简单，也很好治疗，但其它原因却更加严重；充血、发炎、发痒的眼睛可能是对视觉产生真正影响的第一个迹象。我们请李医生讲解了导致眼睛充血的所有情况，这样你就能更好的判断为什么眼睛会有血丝，以及如何治疗。

Allergies
过敏

Not only can an allergic reaction make your eyes feel bad-think itchy, and watery-but allergies also trigger a blotchy kind of redness, which only becomes worse if you scratch your eyes. "Allergic reactions occur when the body's natural immune system overworks or has an excessive response to a harmless stimulus," says Dr. Lee. Almost anything can set off a reaction, but the most common allergens are dust, pollen, pet dander, and detergent.
不仅过敏反应会让你的眼睛难受--发痒、流眼泪--而且过敏还会引起斑点般的发红，如果这时候挠眼睛，情况只会更严重。"如果身体的天然免疫系统超时运作或对无害刺激物过度反应，过敏反应就会发生，"李医生说道。几乎所有的事情都能触发反应，但最常见的过敏原是灰尘、花粉、宠物皮屑和洗涤剂。

The redness will start to go away once you are no longer exposed to the allergen, but that can take a while, depending on the severity of your allergy. To speed things up, splash your eyes with water or use a cool compress on them. Over-the-counter eyedrops designed to counter allergies can help, as can antihistamine meds. Try to figure out what caused your reaction and avoid coming into contact with it again, advises Dr. Lee.
如果你不再接触过敏原，红色血丝就会慢慢消散，但这需要一段时间（取决于过敏的程度）。为了让红色血丝快点消散，可以给眼睛洒点水或是用东西冷敷。抗过敏的非处方眼药水也能起到作用，抗组胺药也可以。试着弄清楚什么导致了过敏反应，避免再次与过敏原接触，李医生建议道。