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because the surface of the eye is covered in a thin film of fluid to make it smooth |
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even if tears cannot spread fast enough by themselves to keep up with the rate of evaporation |
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as driving and staring at a computer screen are among the factors that reduce the blink rate |
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since the different layers of the eye keep it nice and moist, which is necessary for tear production |
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but it can also be reduced by damage to the corneal nerves from contact lenses or eye surgery |