Section outline

  • Close-up of an eye, highlighting eyelashes and reflections in the pupil.

    Did you ever hear the proverb, “the eyes are the windows to the soul”? While it’s true that our eyes often express what we are thinking or feeling, they are windows in another sense as well. Like windows made of glass, the eyes let light in and allow us to see.
    ::你是否听过一句谚语 : “ 眼睛是灵魂的窗口 ” ? 虽然我们的眼睛确实经常表达我们的想法或感觉,但它们也是另一种意义上的窗口。 就像玻璃窗一样,眼睛让光线进入并让我们看到。

    Structure and Function of the Eye
    ::眼睛的结构和功能

    The human eye is an organ that is specialized to collect light and focus images. The structures of the human eye are shown in the Figure . Examine each structure in the diagram as you read about it below.
    ::人类眼睛是专门用来收集光和焦点图像的器官。图中显示的是人类眼睛的结构。您在下面读到的图表中的每一结构。

    Labeled diagram of the human eye showing structures like sclera, iris, lens, and retina.

    • The sclera, also known as the white of the eye, is an opaque outer covering that protects the eye. It keeps light out of the eye except at the center front of the eye.
      ::晶体(又称眼睛的白色)是保护眼睛的不透明外层,除在眼睛的中间外,它保持眼睛的光线。
    • The cornea is a transparent outer covering of the front of the eye. It protects the eye and also acts as a convex lens . A convex lens is thicker in the middle than at the edges and makes rays of light converge, or meet at a point. The shape of the cornea helps focus light that enters the eye.
      ::角角膜是眼睛前部的透明外罩,它保护眼睛,并起到锥形镜的作用。 锥形镜像比边缘厚,使光线聚集,或在一个点相交。 角形的形状帮助了眼部的焦点光。
    • The pupil is an opening in the front of the eye. It looks black because it doesn’t reflect any light. All the light passes through it instead. The pupil controls the amount of light that enters the eye. It automatically gets bigger or smaller to let more or less light in as needed.
      ::学生是眼睛前的开口。 它看起来是黑色的, 因为它没有反映任何光。 所有灯光都会穿过它。 学生控制着进入眼睛的光量。 如果需要, 光线会自动变大或变小, 以便让更多或更少的光线进入眼睛中。
    • The iris is the colored part of the eye. It controls the size of the pupil.
      ::虹膜是眼睛的彩色部分 它控制着学生的大小
    • The lens of the eye is a convex lens. It fine-tunes the focus so an image forms on the retina at the back of the eye. Tiny muscles control the shape of the lens to focus images of close or distant objects.
      ::眼睛的镜片是锥形镜片。 它微调焦点, 从而在眼睛后部的视网膜上形成图像。 微弱的肌肉控制着镜头的形状, 以聚焦近距离物体的图像 。
    • The retina is a membrane lining the back of the eye. The retina has nerve cells called rods and cones that change images to electrical signals. Rods are good at sensing dim light but can’t distinguish different colors of light. Cones can sense colors but not dim light. There are three different types of cones. Each type senses one of the three primary colors of light (red, green, or blue).
      ::视网膜是眼睛后部的膜。 视网膜有神经细胞,叫做棒和锥形,可以将图像转换为电子信号。 罗德善于感知暗淡的光,但无法区分不同的光色。 锥体能感知颜色,而不是暗淡的光。 锥体有三种不同的锥体。 每种类型都感知三种光(红、绿或蓝色)的主要颜色之一。
    • The optic nerve carries electrical signals from the rods and cones to the brain.
      ::视神经将电信号从杆子和锥子传到大脑

    Q: The lens of the eye is a convex lens. How would vision be affected if the lens of the eye was concave instead of convex?
    ::问题:眼睛的透镜是一个阴道透镜。如果眼睛的透镜不是阴道透镜,而是阴道透镜,那么眼睛的透镜会如何受到影响呢?

    A: A concave lens causes rays of light to diverge, or spread apart. It forms a virtual image on the same side of the lens at the object being viewed. Therefore, a concave lens would focus the image in front of the eye, not on the retina inside the eye. No signals would be sent to the brain so vision would not be possible.
    ::甲: 凝固镜片导致光线分解或分散。 它在被观察对象的镜头的同一侧形成虚拟图像。 因此, 凝固镜片会将图像集中在眼睛前, 而不是眼睛内的视网膜上。 没有信号会发送到大脑, 因此视觉是不可能的 。

    How We See
    ::我们如何看待

    The ability to see is called vision . This ability depends on more than healthy eyes. It also depends on certain parts of the brain, because the brain and eyes work together to allow us to see. The eyes collect and focus visible light . The lens and other structures of the eye work together to focus an image on the retina. The image is upside-down and reduced in size, as you can see in the Figure . Cells in the retina change the image to electrical signals that travel to the brain through the optic nerve. The brain interprets the electrical signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see always appears right-side up. The brain also interprets what we are seeing.
    ::视觉能力被称为视觉。 这种能力取决于不仅仅是健康的眼睛, 也取决于大脑的某些部分, 因为大脑和眼睛一起工作, 使我们能看到。 眼睛收集并聚焦可见的光。 眼睛的镜头和其他结构一起工作, 将图像聚焦在视网膜上。 图像向上倾斜, 大小缩小, 正如您在图中看到的那样 。 视网膜中的细胞将图像改变为通过光学神经进入大脑的电信号。 大脑将电子信号解读为形状、 颜色和亮度。 它也将图像解读为是右侧的。 大脑自动这样做, 因此我们所看到的东西总是向右侧看。 大脑也解释我们所看到的东西。

    How light enters the eye and is processed by the brain.

    Q: The part of the brain that processes information from the eyes is the visual cortex. It is located at the back of the brain. How might an injury to the visual cortex affect vision?
    ::问题 : 大脑中从眼睛中处理信息的部分是视觉皮层。 它位于大脑后部。 视觉皮层的伤害会如何影响视觉?

    A: An injury to the visual cortex might cause abnormal vision or even blindness regardless of how well the eyes can gather and focus light.
    ::甲:视觉皮层的损伤可能造成不正常的视力,甚至失明,无论眼睛能聚集多深和聚焦光线。

     

    Summary
    ::摘要

    • The human eye is an organ that is specialized to collect light and focus images. Light enters through transparent structures at the front of the eye. It is focused by the cornea and lens on the retina at the back of the eye.
      ::人眼是专门收集光和焦点图像的器官。 光通过眼睛前面透明的结构进入, 以眼后视网膜上的角膜和透镜为焦点。
    • The ability to see is called vision. The brain and eyes work together to allow us to see. The eyes collect and focus visible light and change it to electrical signals that travel to the brain. The brain interprets the signals and “tells” us what we are seeing.
      ::视觉能力被称为视觉。 大脑和眼睛一起工作,让我们能看到。 眼睛收集和集中可见的光线,并把它改变为通向大脑的电信号。 大脑解释信号和我们所看到的“言语 ” 。

    Review
    ::回顾

    1. Create a flowchart to summarize how the eye gathers and focuses light.
      ::创建流程图以总结眼睛如何聚集和聚焦光。
    2. Explain the meaning of the following sentence: The eyes sense light but the brain sees.
      ::解释以下一句的含义:眼睛感知光线,但大脑会看到。