Eyes，the Gift from Heaven

1.引言

有人说，“眼睛是心灵的窗户”，透过它，有可能接触到人的内心世界。

想象在月光下的小径，温暖的微风从山林的一侧吹来，带来了清新的气息，浮动着的树枝沙沙作响。这时候周围有不知名的虫儿，躲在丰茂的树丛里，你一言，我一句，任凭情绪而欢唱，不远处的小溪流也在不安分的流淌，发出欢快清脆的响声。

一对情侣面对站立在在一小片空地上深情对视，今夜的月光很亮，亮到足够能在对方的眼中看见自己的样子。这时候你的眼中有我，我的眼中有你，忽然一股来自远古的能量，悄然带来了美妙的音乐和花香，一切都是自然平和，仿佛这是来自上天的赐福。两人的内心世界已经有了太多的触碰和连接，啊，爱情让两人变得美丽圆满。

悄然间，无数萤火虫从林间跳跃舞动，汇聚成一条细长，弯曲的光带，仿佛是一条金色的哈达，高低起伏，随意铺开。点亮在情人的眼中。

。。。

眼睛，不同物种及种族之间，形态各异。它们晶莹剔透，明亮透彻。有的狡黠，有的智慧，有的茫然，有的坚定；有的血丝密布，有的柔和安宁，有的眼睛拥有蓝宝石的色彩，有的却拥有狭长的瞳孔，种类繁多，神秘莫测，人们很想去研究了解它，越深入了解，越感叹其复杂，细微之处却丰富而博大，仿佛深藏整个宇宙，让人只能靠近，却不知终点在何处。

2.Which structure in the eye may change in size under different conditions of light intensity?

The size of your pupils is controlled by muscles in the colored part of your eye (iris) and the amount of light reaching your eyes. In bright light, your pupils constrict (get smaller) to prevent too much light from entering your eyes. In dim lighting, your pupils dilate (get larger) to allow more light in.

Generally, normal pupils range in size from 2.0 to 4.0 millimeters (mm) in bright light, and 4.0 to 8.0 mm in the dark. To some degree, pupil size tends to get smaller with age.

In one study of 500 Americans ages 18 to 34 years, average pupil sizes in three different lighting conditions were found to be:

• 3.35 mm in direct light (a penlight shined directly at the eye for 15 seconds)
• 3.86 mm in normal room lighting
• 6.41 mm in near-total darkness

来自 <https://www.allaboutvision.com/conditions/dilated-pupils.htm>

3.Aperture, the Simplified Structure of Eyes

In consumer optical products — most commonly cameras — aperture describes the size of the hole that lets light into a device. Cameras use mechanical diaphragms to control how much light passes into the camera body and strikes the image sensor or film. That diaphragm works a lot like the irises in your eyes; it contracts or expands depending on how much light is needed. Aperture refers to the diameter of the opening. It’s like the dark, black pupils of your eyes, the actual orifice that lets light pour through.

The exposure settings you choose dictate both the duration and the amount of light entering the camera. Shutter speed controls duration, while aperture allows you to adjust the volume. The larger the aperture diameter is, the greater the amount of light flowing through the camera’s lens, which lets you control aperture size.

来自 https://electronics.howstuffworks.com/cameras-photography/tips/aperture.htm

4.The Detailed Structure of a Aperture

结构原理：是经典曲柄滑块结构的衍生版本，连杆和滑块合二为一。