《采桑子》‧宋‧晏幾道

紅窗碧玉新名舊，
猶綰雙螺。
一寸秋波，
千斛明珠覺未多。

小來竹馬同遊客，
慣聽清歌。
今日蹉跎，
惱亂工夫暈翠蛾。

 

秋波明珠是何物？顧愷之畫人無阿堵！傳神寫照能勾魂攝魄，難怪耶靈魂衷情柏拉圖！！交子夢裡聞聲未睹，孔方得貝不識寶物︰

一人不識是何人，彷彿正問著另一人，也不識是何人？只聽得︰

老 子曰：『有物混成，先天地生，惟象無形，窈窈冥冥，寂寥淡漠 ，不聞其聲，吾強為之名，字之曰道。』夫道者，高不可極，深不可測，苞裹天地，稟受無形，原流泏泏，沖而不盈，濁以靜之徐清，施之無窮，無所朝夕，表之不 盈一握，約而能張，幽而能明，柔而能剛，含陰吐陽，而章三光；山以之高，淵以之深，獸以之走，鳥以之飛，麟以之遊，鳳以之翔，星曆以之行；以亡取存，以卑 取尊，以退取先。古者三皇，得道之統，立於中央，神與化遊，以撫四方。是故能天運地墆，輪轉而無廢，水流而不止，與物終始。風興雲蒸，雷聲雨降，並應無 窮，已雕已琢，還復於樸。無為為之而合乎生死，無為言之而通乎德，恬愉無矜而得乎和，有萬不同而便乎生。和陰陽，節四時，調五行，潤乎草木，浸乎金石，禽 獸碩大，毫毛潤澤，鳥卵不敗，獸胎不殰，父無喪子之憂，兄無哭弟之哀，童子不孤，婦人不孀，虹蜺不見，盜賊不行，含德之所致也。大常之道，生物而不有，成 化而不宰，萬物恃之而生，莫知其德，恃之而死，莫之能怨，收藏畜積而不加富，布施稟受而不益貧；忽兮怳兮，不可為象兮，怳兮忽兮，用不詘兮，窈兮冥兮，應 化無形兮，遂兮通兮，不虛動兮，與剛柔卷舒兮，與陰陽俯仰兮。

，心想，這說的不就是文子的首篇《道原》嗎？，…

周失其道，五七后兮，勢水火兮，殷金夏貝，泉市之流，不識汝祖？問道方外耶！正想細聽，一陣喧嘩回過神來，已不復入夢矣，自此經常昏昏失魂悶悶落魄。

─── 摘自《孔方之阿堵物》

 

既然老子曰︰有，名萬物之母。

道可道，非常道。名可名，非常名。無，名天地之始。有，名萬物之母。故常無，欲以觀其妙。常有，欲以觀其徼。此兩者同出而異名，同謂之玄。玄之又玄，眾妙之門。

 

辨物豈可不知名乎？？！！

角膜→房水【前室】→虹膜【瞳孔】→晶狀體→玻璃體【後部】→視網膜

囫圇者焉知其糊不糊塗！！？？

虹膜

虹膜又稱黃仁，眼睛構造的一部分，虹膜中心有一圓形開口，稱為瞳孔，猶如相機當中可調整大小的光圈，內含色素決定眼睛的顏色 。日間光線較為強烈時，虹膜會收縮，只使一小束光線穿透瞳孔，進入眼睛；當進入黑暗環境中，虹膜就會往後退縮，使瞳孔變大，讓更多的光線進入眼睛，多數的脊椎動物的眼睛都有虹膜。因為每個人的虹膜都是不同的，所以也用於身份標識。

雙色虹膜與中央的黑色瞳孔

Iris (anatomy)

The iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina. Eye color is defined by that of the iris. In optical terms, the pupil is the eye’s aperture, while the iris is the diaphragm that serves as the aperture stop.

Iris is the blue area, with the pupil (the circular black spot) in its center, and surrounded by the white sclera. Overlying cornea is completely transparent so is not visible, except the high-gloss luster it gives the eye. Also pictured are the red blood vessels within the sclera. These structures are easily visible on any person’s eyes.

瞳孔

瞳孔又稱瞳神，是眼球血管膜的前部虹膜中心的圓孔。沿瞳孔環形排列的平滑肌叫瞳孔括約肌，收縮時使瞳孔縮小，沿瞳孔放射狀排列的平滑肌叫瞳孔放大肌，收縮時使瞳孔放大，調節進入眼球的光線量。因為內部吸收的關係，通常外觀呈黑色。

人眼近看。中間黑色的部分為瞳孔，周圍棕綠色部分為虹膜，外部白色部分為鞏膜。鞏膜中心最前面為透明的角膜。

動物的瞳孔

人類和很多動物（除了少數魚類）的瞳孔由不自覺的虹膜伸縮控制大小，以調節入眼內的光線強度。此稱為瞳孔反射。例如，人類瞳孔在強光下直徑大約1.5毫米，在暗淡光線中擴大到8毫米左右。

動物的瞳孔形狀由玻璃體的光學特性、視網膜的形狀和敏感度，以及物種的生存環境和需要決定。一般為圓形或縫狀，有些水生動物的瞳孔則有更奇異的形狀。

縫狀瞳孔常見於活動在不同光線強度下的動物。在強光下，這類瞳孔縮成細縫，然而仍然允許光線落到視網膜很大部分。開縫的方向可能與動物需要以高敏感度察覺的運動方向有關。例如家貓的瞳孔為豎立，便於察覺老鼠等獵物的橫向運動。很多蛇類也是縫狀瞳孔。

在用閃光燈照相的時候，瞳孔來不及及時關閉，閃光照亮眼底血管豐富的視網膜，形成紅眼現象。具有「防紅眼」功能的相機是預閃一次光，使瞳孔在正式閃光的時候已經達到收縮狀態。

Pupil

The pupil is a hole located in the centre of the iris of the eye that allows light to strike the retina.^[1] It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil.

In humans the pupil is round, but other species, such as some cats, have vertical slit pupils, goats have horizontally oriented pupils, and some catfish have annular types.^[2] In optical terms, the anatomical pupil is the eye’s aperture and the iris is the aperture stop. The image of the pupil as seen from outside the eye is the entrance pupil, which does not exactly correspond to the location and size of the physical pupil because it is magnified by the cornea. On the inner edge lies a prominent structure, the collarette, marking the junction of the embryonic pupillary membrane covering the embryonic pupil.

The human eye
The pupil is the central transparent area (showing as black). The grey/blue area surrounding it is the iris. The white outer area is the sclera, the central transparent part of which is the cornea.

Controlling

The iris is a contractile structure, consisting mainly of smooth muscle, surrounding the pupil. Light enters the eye through the pupil, and the iris regulates the amount of light by controlling the size of the pupil. The iris contains two groups of smooth muscles; a circular group called the sphincter pupillae, and a radial group called the dilator pupillae. When the sphincter pupillae contract, the iris decreases or constricts the size of the pupil. The dilator pupillae, innervated by sympathetic nerves from the superior cervical ganglion, cause the pupil to dilate when they contract. These muscles are sometimes referred to as intrinsic eye muscles. The sensory pathway (rod or cone, bipolar, ganglion) is linked with its counterpart in the other eye by a partial crossover of each eye’s fibers. This causes the effect in one eye to carry over to the other. If the drug pilocarpine is administered, the pupils will constrict and accommodation is increased due to the parasympathetic action on the circular muscle fibers, conversely, atropine will cause paralysis of accommodation (cycloplegia) and dilation of the pupil.

Optic effects

When bright light is shone on the eye, light sensitive cells in the retina, including rod and cone photoreceptors and melanopsin ganglion cells, will send signals to the oculomotor nerve, specifically the parasympathetic part coming from the Edinger-Westphal nucleus, which terminates on the circular iris sphincter muscle. When this muscle contracts, it reduces the size of the pupil. This is the pupillary light reflex, which is an important test of brainstem function. Furthermore, the pupil will dilate if a person sees an object of interest.

The pupil gets wider in the dark but narrower in light. When narrow, the diameter is 2 to 4 millimeters. In the dark it will be the same at first, but will approach the maximum distance for a wide pupil 3 to 8 mm. In any human age group there is however considerable variation in maximal pupil size. For example, at the peak age of 15, the dark-adapted pupil can vary from 4 mm to 9 mm with different individuals. After 25 years of age the average pupil size decreases, though not at a steady rate.^[3][4] At this stage the pupils do not remain completely still, therefore may lead to oscillation, which may intensify and become known as hippus. The constriction of the pupil and near vision are closely tied. In bright light, the pupils constrict to prevent aberrations of light rays and thus attain their expected acuity; in the dark this is not necessary, so it is chiefly concerned with admitting sufficient light into the eye.^[5]

A condition called bene dilitatism occurs when the optic nerves are partially damaged. This condition is typified by chronically widened pupils due to the decreased ability of the optic nerves to respond to light. In normal lighting, people afflicted with this condition normally have dilated pupils, and bright lighting can cause pain. At the other end of the spectrum, people with this condition have trouble seeing in darkness. It is necessary for these people to be especially careful when driving at night due to their inability to see objects in their full perspective. This condition is not otherwise dangerous.

Diaphragm (optics)

In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through the lens. The centre of the diaphragm’s aperture coincides with the optical axis of the lens system.

Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris.

See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm.

Nine-blade iris

Aperture

In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are, which is of great importance for the appearance at the image plane.^[2] If an aperture is narrow, then highly collimated rays are admitted, resulting in a sharp focus at the image plane. A wide aperture admits uncollimated rays, resulting in a sharp focus only for rays coming from a certain distance. This means that a wide aperture results in an image that is sharp for things at the correct distance. The aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane (the narrower the aperture, the darker the image for a given exposure time). In the human eye, the pupil is the aperture.

An optical system typically has many openings, or structures that limit the ray bundles (ray bundles are also known as pencils of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that primarily determines the ray cone angle and brightness at the image point.

In some contexts, especially in photography and astronomy, aperture refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope the aperture stop is typically the edges of the objective lens or mirror (or of the mount that holds it). One then speaks of a telescope as having, for example, a 100 centimeter aperture. Note that the aperture stop is not necessarily the smallest stop in the system. Magnification and demagnification by lenses and other elements can cause a relatively large stop to be the aperture stop for the system. In astrophotography the aperture may be given as a linear measure (for example in inches or mm) or as the dimensionless ratio between that measure and the focal length. In other photography it is usually given as a ratio.

Sometimes stops and diaphragms are called apertures, even when they are not the aperture stop of the system.

The word aperture is also used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy for example, a photometric aperture around a star usually corresponds to a circular window around the image of a star within which the light intensity is assumed.^[3]

Diagram of decreasing aperture sizes (increasing f-numbers) for “full stop” increments (factor of two aperture area per stop)