Covid-19 and the Eyes: What Science Knows So Far新冠肺炎和眼睛：科学家已经知道的

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Summary
摘要

How Does Covid-19 Affect the Eyes: Covid-19 can sometimes cause ocular symptoms, although the documented prevalence varies widely — from 0% to 31.6%. The most common ocular signs are red-eye, conjunctivitis, light intolerance, and eye itchiness.
新冠病毒如何影响眼睛：尽管记录的患病率在0％-31.6％之间波动，差距很大，但新冠病毒有时会引起眼部症状。最常见的症状是红眼，结膜炎，不耐光和眼痒。

Covid-19 Can Infect the Eyes: SARS-CoV-2 genes have been discovered in the conjunctiva, retina, and eye secretions of infected patients. The ACE2 receptor is also present in the eye conjunctiva and retina. And SARS-CoV-2 replication in conjunctival cells has been confirmed. However, Covid-19 may still harm the eyes in other ways, such as by inducing excessive inflammation, hypoxia, or blood clotting.
新冠病毒可以感染眼睛：在感染患者的结膜、视网膜和眼睛的分泌物中发现了SARS-CoV-2病毒。ACE2受体也存在于眼结膜和视网膜中，已证实SARS-CoV-2可在结膜细胞中复制。但是，新冠病毒仍可以其他方式伤害眼睛，例如引起过度的炎症，缺氧或血液凝结。

Covid-19 Eye Transmission Remains Unclear: Although there is only anecdotal and no hard evidence of eye transmission, health authorities still advice for eye protection in healthcare workers. Even if eye transmission is possible, it should be of lesser real-life significance than droplets.
新冠病毒在眼部的传播仍不清楚：尽管只有传闻，也没有确凿的眼部感染证据，但卫生组织仍建议医护人员保护眼睛。即使可以透过眼睛传染，对生活的影响也比飞沫传播小。

How Covid-19 Affect the Eyes
新冠病毒如何影响眼睛？

A paper on this topic, “Ocular manifestations of coronavirus disease 2019,” is published in Clinical and Experimental Ophthalmology in June. Researchers in Turkey examined 93 hospitalized patients with Covid-19, of which 20 (21.5%) presented at least one ocular (eye) symptoms. The specifics are:
关于这个话题，有篇论文“ 2019年冠状病毒疾病的眼部表现 ” 6月在《临床和实验眼科》上发表。土耳其的研究人员对93例感染新冠病毒的住院患者进行了检查，其中有20例（21.5％）表现出至少有一种的眼部症状。具体为

Hyperemia (red eye): 20 (21.5%) patients.
Epiphora (excessive tear flow): 9 (9.7%) patients.
Increased secretion (of green or yellow eye fluid): 6 (6.5%) patients.
Chemosis (swelling of conjunctiva): 3 (3.2%) patients.
Follicular conjunctivitis (more severe chemosis): 8 (8.6%) patients.
Episcleritis (inflammation of eye sclera): 2 (2.2%) patients.
Photophobia (intolerance to light): 15 (16.1%) patients.
Itchiness: 13 (15.7%) patients.
Burning sensation: 7 (8.4%) patients.
Gritty feeling (eye irritation that feels like sand): 5 (6.0%) patients.
Blurred vision: 4 (4.8%) patients.
充血（红眼）：20（21.5％）位患者。
眼水过多：9名（9.7％）位患者。
（绿色或黄色眼液的）分泌增加：6（6.5％）位患者。
化学病（结膜肿胀）：3（3.2％）位患者。
滤泡性结膜炎（较严重的化学反应）：8例（8.6％）。
上巩膜炎（眼巩膜发炎）：2例（2.2％）位患者。
畏光（不耐光）：15（16.1％）位患者。
瘙痒：13（15.7％）位患者。
灼痛感：7（8.4％）位患者。
沙眼（感觉像沙子的眼睛刺激）：5（6.0％）位患者。
视力模糊：4（4.8％）位患者。

Risk factors for Covid-19 ocular problems were old age and elevated inflammation — as indicated by increased fever, neutrophil/lymphocyte ratio, C-reactive protein, and erythrocyte sedimentation rate. However, they did not examine other disease outcomes, such as hospital stay or death rate.
会让新冠病毒引发问题的危险因素是年纪大和眼部发言——如发烧、中性粒细胞/淋巴细胞的比例，C反应蛋白和红细胞的沉降率。但它们没有检查其他疾病的结果，如住院时长和死亡率。

Other research has also documented cases of ocular signs in Covid-19, as summarized in a table of an earlier June review titled “Covid-19 and the eye: how much do we really know? A best-evidence review.” The review shows that the prevalence of Covid-19 ocular symptoms varies widely from 0% to 31.6%. (Note that this review did not include the study above.)
其他研究还记录了新冠病毒患者的眼部症状，如六月初就发表了一篇题为“冠状病毒和眼睛：我们真的知道多少？最佳证据审查。” 该审查表明，新冠患者的眼部症状的患病率从0％到31.6％不等，差异很大。（请注意，此评价未包括上述研究。）

Source (CC BY): Emparan et al. (2020). Covid-19 and the eye: how much do we really know? A best evidence review. Arquivos Brasileiros de Oftalmologia, 83(3), 250–261. https://doi.org/10.5935/0004-2749.20200067
来源：Emparan等。（2020）。新冠肺炎和眼睛：我们真正知道多少？最佳证据审查。Artalvos Brasileiros de Oftalmologia，83（3），250-261。https://doi.org/10.5935/0004-2749.20200067

On the Retina and Optic Nerve Connection
在视网膜和视神经连接上

A May research paper, “Detection of SARS-CoV-2 in Human Retinal Biopsies of Deceased Covid-19 Patients,” found SARS-CoV-2 genetic material in the retina of three out of 12 deceased patients. And prior research has, in fact, found ACE2 expression in the human retina.
5月的一项研究论文“ 关于在已故新冠肺炎患者的视网膜中检测新冠病毒的检测发现，在12例死者中有3例患者的视网膜中存在新冠病毒遗传物质。实际上，先前的研究已经发现了ACE2在人类的视网膜中出现。

(The retina is the back part of the eye where the optic nerve is placed. Any information the retina receives is relayed to the brain via the optic nerve.)
（视网膜在放置视神经的眼睛后部。视网膜接收到的任何信息都通过视神经传递到大脑。）

Cancer Research UK / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)
英国癌症研究中心/ CC BY-SA（https://creativecommons.org/licenses/by-sa/4.0）

A May study in The Lancet, “Retinal findings in patients with Covid-19,” has also shed light on this topic. Using a non-invasive eye imaging technique called optical coherence tomography (OCT), they saw damages to the retina and optic nerve in all 12 Covid-19 patients tested. However, the good news is that these patients showed no visual impairment. “Although animal models [of coronaviruses] suggest ocular lesions could include retinitis and optic neuritis, this is, to the best of our knowledge, the first report of retinal findings possibly associated with Covid-19 infection in humans,” the authors closed.

在《柳叶刀》5月份的报告上，“患者的视网膜发现有冠状病毒，”也对这个话题继续探索。他们使用一种称为光学相干断层扫描（OCT）的无创眼部成像技术，在接受测试的12位新冠患者的视网膜和视神经上看到了损伤。但是，好消息是这些患者没有视力障碍。作者总结“尽管[冠状病毒]的动物模型显示眼部病变可能包括视网膜炎和视神经炎，但据我们所知，这是第一份关于视网膜损伤可能与冠状病毒感染有关的报告。”

Later in July, another published OCT study, “Optic nerve analysis in COVID‐19 patients,” found increased inflammation of the optic nerves in all five patients tested, compared to when they did not have Covid-19. And, again, none had a visual loss, which implies that the optic nerve inflammation may not be severe enough to rupture the nerve completely.
在7月下旬，另一项已发表的OCT研究表明“ 在新冠肺炎患者身上进行的视神经分析 ”发现，与没有新冠肺炎时相比，接受测试的五位患者的视神经炎症都有增加。而且，没有人有视力丧失，这意味着视神经发炎可能还不够严重，不能完全破坏神经。

Covid-19 Can Infect the Eyes
新冠肺炎可以影响眼睛

Back in February, Chinese researchers (Xia et al.) detected, for the first time, SARS-CoV-2 genetic material in tears and conjunctival secretions in one patient (3.3%) out of 30. That one patient also had conjunctivitis (inflamed eye membranes), while the remaining 29 did not have it.
早在二月，中国研究人员首次在30名患者中一位患者（3.3％）的眼泪和结膜分泌物中检测到新冠病毒遗传物质。该患者还患有结膜炎（眼膜发炎），而其余的29位患者没有。

Other research shows a similar trend. Sometimes SARS-CoV-2 is present in eye fluids, and sometimes it is not; the prevalence ranges from 0% to 7.14%, as compiled in a table of the June review. These data suggest that it is rare for SARS-CoV-2 to infect the eyes, although it can happen sometimes.
其他研究也显示出类似的趋势。有时新冠病毒存在于眼液中，有时则不存在。如6月的审查表格所述，患病率介于0％至7.14％之间。这些数据表明，新冠病毒很少会感染眼睛，尽管它有时会发生。

Source (CC BY): Emparan et al. (2020). Covid-19 and the eye: how much do we really know? A best evidence review. Arquivos Brasileiros de Oftalmologia, 83(3), 250–261. https://doi.org/10.5935/0004-2749.20200067
来源：Emparan等。（2020）。新冠肺炎和眼睛：我们真正知道多少？最佳证据审查。Artalvos Brasileiros de Oftalmologia，83（3），250-261。https://doi.org/10.5935/0004-2749.20200067

The fact that the eye conjunctiva expresses ACE2 receptors, according to a study in Nature, supports the possibility of Covid-19 eye infection. A July paper in the Lancet Respiratory Medicine confirms that SARS-CoV-2 replicates in conjunctival cells (in a lab dish) to a greater extent than SARS-CoV-1. “The conjunctival epithelium and conducting airways appear to be potential portals of infection for SARS-CoV-2,” the study authors concluded.
根据《自然》杂志的一项研究显示，眼结膜可作为ACE2受体的事实佐证了冠状病毒可以感染眼睛的可能性。《柳叶刀》呼吸医学杂志于7月发表的一篇论文证实，新冠病毒（SARS-CoV-2）在结膜细胞（实验室培养皿）中的复制程度比SARS-CoV-1更大。研究作者总结说：“结膜上皮和导气管似乎是新冠病毒的潜在感染门户。”

Even if SARS-CoV-2 does not infect the eyes, it may still harm the eyes in indirect ways. Covid-19-induced excessive inflammation, hypoxia (low oxygen levels in the blood), or blood clotting all can disturb distant organs.
即使新冠病毒不会感染眼睛，也可能间接伤害眼睛。新冠肺炎引起的过度炎症，缺氧（血液中的低氧水平）或血液凝结都会干扰远处的器官。

Covid-19 Eye Transmission Remains Unclear
冠状病毒的眼部传染过程仍然不清楚

There are also a few anecdotal reports of Covid-19 transmission via the eyes. In brief, healthcare workers who wore a mask and appropriate personal protective equipment (PPE), but no eye protection, somehow contracted Covid-19 and conjunctivitis.
也有一些眼睛可以传染冠状病毒的传闻。简而言之，戴口罩、穿个人防护设备（PPE）、但没有护目镜的医护人员有可能感染新冠肺炎和结膜炎。

But the verdict is still out there. “Although there is currently no confirmed conjunctival transmission route, the authors agree with the WHO and other organizations´ recommendations that PPE must include eye protection such as goggles or face shields,” stated the June review. However, even if Covid-19 eye transmission is possible, it should be of lesser real-life significance than droplets.
但判决仍然存在。6月有评论表示“尽管目前尚无确定的结膜传播途径，但作者同意WHO和其他组织的建议，即个人防护设备（PPE）必须包括护目镜或面罩等面部防护用具。”。但是，即使新冠肺炎可以感染眼睛，现实生活中它也没有飞沫传播重要。