Keeping a pet cat puts owners at greater risk of going blind, but a dog appears to protect eyesight, a new study suggests.

一项最新研究表明，养猫会增加主人失明的风险，但是养狗却能保护主人的视力。

Scientists have discovered that dogs and cats carry antigens which can prompt different immune responses in humans.

科学家们发现狗和猫身上都携带能激起人体的不同免疫反应的抗原。

While the allergen which dogs carry reduces the chance of developing glaucoma – the second leading cause of blindness in theUK– owning a cat nearly doubles the risk of contracting the eye disease.

狗身上携带的过敏原会降低主人患青光眼的几率，在英国，青光眼是导致人们失明的第二大诱因，而养猫让主人感染这一眼疾的风险增加了一倍。

Many pet owners suffer mild allergic¹ reactions to their pets but still choose to keep them. However the new study suggests that even a small immune response could lead to blindness.

许多宠物主人对他们的宠物都有轻微的过敏反应，但是却坚持养宠物。然而最新研究表明，即使是个很小的免疫反应都有导致失明的危险。

The study by the University of California, Los Angeles, found that cat owners who reacted to their pet allergen had a 90 per cent increased risk of glaucoma compared with non-pet owners. But dog owners were 20 per cent less likely to develop the debilitation² condition.

加州大学洛杉矶分校的这项研究发现，如果宠物猫的主人对他们的宠物过敏的话，其患青光眼的风险比没养宠物的人高90%。但是，宠物狗的主人出现视力减弱的几率却很可能比一般人低20%。

Keeping a dog also has the added benefit that owners are outside more which has been proven to protect against short-sightedness.

养狗的主人需要经常在户外活动，这同时也有助于保护主人的视力，不会近视。

“Not only is Fido man's best friend, he may also save your sight,” said British laser eye surgeon Dr David Allamby.

英国激光眼科医生大卫·阿兰比博士说：“宠物狗不仅是人类最好的朋友，还可以保护你的视力。”

“Cats could cause our immune system to react in a way that predispose eyes to the development of glaucoma.

“而宠物猫却会诱发我们的免疫系统做出不同的反应，导致青光眼的出现。”

“Exposure to dogs appears to be linked to the opposite effect and could be protective against the disease.”

“与狗接触却会产生相反的作用，并且还能防青光眼。”

Glaucoma occurs when fluid in the eyeball stops draining efficiently³, causing a build-up of pressure which damages the optic nerve and nerve fibres from the retina. Previous studies have suggested that inflammation can drive the disease and the researchers wanted to find out if that could be triggered by pet allergens.

青光眼是由于眼球中的液体不能有效排出，导致眼内压力累积，从而导致视网膜的视神经和神经纤维受损导致的。早前的研究表明炎症能引起青光眼，研究人员同时还想弄清楚，宠物过敏原是否也会导致青光眼。

Animals frequently groom⁴ themselves so allergens from saliva⁵ and secretions⁶ spread throughout the home, becoming airborne easily where they can be inhaled⁷ by humans.

由于动物们频繁地梳理它们自己，所以来自唾液和分泌物的过敏原很快就扩散到整个家里，接着又通过空气传播很容易就被人类吸入体内。

The researchers believe that dogs are healthier for humans because they spend more time outdoors.

研究人员认为，对人类来说，狗更健康一些，因为它们大多数时间都在户外。

“The protective effect of dogs could be due to their natural antigens in their dead skin, but might also be because they spend more time outdoors and are happy to get dirty, whereas cats are cleaner animals,” said Dr Anne Coleman, of UCLA.

加州大学洛杉矶分校的安妮·科尔曼博士表示：“狗的防护作用可能是来自于它们死皮内的自然抗原，但是也可能是由于它们更多时间都在户外，而且把自己弄脏了也很开心，然而，猫却是种爱干净的动物。”

“We already know that exposure to dogs and the germs and bacteria they carry can be good for the immune system. Now it seems to be the case for the eyes too.

“我们已经知道接触狗和它们携带的细菌对人类免疫系统有益。现在发现这似乎对人类的眼睛也有益处。

“Allergens from cats may have biochemical or physical properties that trigger antibodies targeting the optic nerve, while dog allergens may behave differently, possibly because dogs spend more time outdoors."

“猫身上携带的过敏原可能有生物化学性或物理性特征，能诱发针对视神经的抗体，而狗身上携带的过敏原起到的作用却不同，可能是因为狗大多数时间都在户外。”