Eye diagram

• Home • Science Menu Toggle • Plants Facts • Animal Facts • Physics • Chemistry • Human Body • Earth Science • Science Quiz • General Science Questions For Kids • Math • Solar System Menu Toggle • Solar System Facts • Mercury Facts • Venus Facts • Earth Facts • Mars Facts • Jupiter Facts • Saturn Facts • Uranus Facts • Neptune Facts • Pluto Facts • Geography Menu Toggle • Continents Menu Toggle • Asia Continent • Africa Continent • Antarctica Continent • Australasia & Oceania Continent • Europe Continent • North America Continent • South America Continent • Countries • Mountains • Oceans • Quiz • Jokes • Parents Corner ➤ Sclera The Sclera is a strong outer white part of the eye . It is also known as the “white”. The sclera provides the eye with structural strength and protection. ➤ Cornea The cornea is the transparent part of the eye that covers the front portion of the eye. It covers the pupil, iris and anterior chamber. There are no blood vessels present in the cornea, but instead of blood vessels it contains many nerve endings that make it extremely sensitive. That is why it is so painful when we get an eyelash in our eye. ➤ Functions of the cornea The cornea helps the eye in several ways: The cornea protects the eye from germs, dust, and other harmful matter with the help of eyelids, the eye socket, tears, and the sclera. It acts like a window that controls and focuses the entry of light into the eye. It contributes around 70% of the eye’s total focusing power. ➤ Ante...

Orbit (anterior view) The eyes are essential for our daily experience, since about 70% of information we gather is by seeing. They are placed within the Besides the eyes, the orbits host several structures that support the This page will discuss the Key facts about the orbit and eyes Orbit definition Bony cavity within the skull that houses the eye and its associated structures (muscles of the eye, eyelid, periorbital fat, lacrimal apparatus) Bones of the orbit Maxilla, zygomatic bone, frontal bone, ethmoid bone, lacrimal bone, sphenoid bone and palatine bone Structure of the eye Cornea, anterior chamber, lens, vitreous chamber and retina Muscles of the eye Extrinsic: Superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique, levator palpebrae superioris Intrinsic: Innervation of the eye Vision: Optic nerve (CN II) Muscles: Oculomotor (CN III), trochlear (CN IV) and abducens (CN VI) nerves Blood supply of the eye Ophthalmic artery, vorticose veins + Show all Bones of the orbit The The walls of the orbit contain several fissures, openings and fossae which are important for housing the orbital structures, and for neurovascular communication of the orbital content with the central nervous system. Some of the most important openings are the superior orbital fissure and its downstairs neighbour, the inferior orbital fissure. More about them and all the other landmarks of the orbital bones can be found in the following article and quizze...

There are two types of eye muscles: extrinsic muscles that control eye movement and position, and intrinsic muscles that control near focusing and how much light enters the eye. Extrinsic eye muscles (also called extraocular muscles) are attached to the outside of the eyeball and enable the eyes to move in all directions of sight. There are six extraocular eye muscles and one muscle that controls movement in the upper eyelid. Though the extraocular muscles are found within the The main function of the extraocular eye muscles is to control eye movement and eye alignment. They are different from the intrinsic eye muscles, which enable the eye to focus on near objects and control how much light enters the eye. Extraocular eye muscles and their functions Among the extraocular muscles, there are four straight (rectus) muscles and two oblique muscles that work together to move the eye from side to side, up and down, and control its rotation. Additionally, a muscle called the levator palpebrae superioris (LPS) raises the upper eyelid and keeps it in position. All seven of these eye movement muscles are controlled by three cranial nerves: the oculomotor nerve, trochlear nerve and abducens nerve. Recti muscles The eye has four recti muscles, all of which attach to the front half of the eye (anterior to the equator of the eye). These muscles are: • Superior rectus muscle • Medial rectus muscle • Lateral rectus muscle • Inferior rectus muscle Each of the eye’s recti muscles originate...

The Human Eye is the main visual organ of our human body. It is just like a camera having a lens in it. There are different colors of human eyes. Have you noticed it? This is specially due to the color of eyes. There are many things that are in the eye. Even the formation of an image includes a number of processes. All this information you are going to receive in this article in brief. Human Eye due to not being taken care of properly results in getting defected and you will know about such defects here also. Firstly let's have a look at the human eye. The human eye is one of the most important organs of the human body which when interacted with light gives us the sense of sight or vision. There are two kinds of cells in the eye namely rods and cones. The basic functions of Rods and Cones are conscious light perception, color differentiation and depth perception. The human eye is capable of distinguishing between about 10 million colors, and it can also detect a single photo. The human eye is a part of the sensory nervous system. Labeled Diagram of Human Eye The eyes of all mammals consist of a non-image-forming photosensitive ganglion within the retina which receives light, adjusts the dimensions of the pupil, regulates the availability of melatonin hormones, and also entertains the body clock. • The anterior chamber of the eyes is the space between the cornea and therefore the iris and is crammed with a lubricating fluid, aqueous humor. • The vascular layer of the eye , ...

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One of the most important parts of the eye isn't a structure at all — it's an open space. It's the pupil of the eye. Pupil Definition The pupil is the opening in the center of the iris (the structure that gives our eyes their color). The function of the pupil is to allow light to enter the Typically, the pupils appear perfectly round, equal in size and black in color. The black color is because light that passes through the pupil is absorbed by the retina and is not reflected back (in normal lighting). If the pupil has a cloudy or pale color, typically this is because the lens of the eye (which is located directly behind the pupil) has become opaque due to the formation of a There's another common situation when the pupil of the eye changes color — when someone takes your photo using the camera's flash function. Depending on your direction of gaze when the photo is taken, your pupils might appear bright red. This is due to the intense light from the flash being reflected by the red color of the retina. [Read more about Pupil Function Together, the iris and pupil control how much light enters the eye. Using the analogy of a camera, the pupil is the aperture of the eye and the iris is the diaphragm that controls the size of the aperture. The size of the pupil is controlled by muscles within the In low-light conditions, the pupil dilates so more light can reach the retina to improve night vision. In bright conditions, the pupil constricts to limit how much light enters the ey...

Analyzing Data using Eye Diagrams Using Eye Diagrams • • • • • • • Other PLTS constructs measurement-based eye diagrams (or patterns) by convolving the calculated time domain impulse response (generated from frequency domain measurement data) with a synthesized pattern of bit sequences. The following is a simplified block diagram of the eye diagram creation process. With eye diagrams you can see signal quality with one display, you can diagnose problems, such as attenuation, noise, jitter, and dispersion that arise or characterize specific parts of the system. You can then view the measurement in the Time Domain mode to help isolate the source of the problem. NRZ (non return to zero), also known as PAM2, is a Pulse Amplitude Modulated (PAM) signal with two amplitude levels. This signaling method transmits one bit of data for every bit, unit interval, or symbol interval. NRZ (PAM2) Signal Instead of a 0 and 1 level as in NRZ, PAM4 has four amplitude levels (0, 1, 2, and 3). This signaling method transmits 2 bits of data for every symbol. As a result, PAM4 transmits twice as much data per unit time. PAM4 Signal The eye diagrams shown below identify key eye diagram definitions. 2-Level Eye Diagram (PAM2) 4-Level Eye Diagram (PAM4) 1 Zero Level Zero Level is a measure of the mean value of the logical 0 of an eye diagram. 2 One Level One Level is a measure of the mean value of the logical 1 of an eye diagram. 3 Rise Time Rise time is a measure of the transition time of the data...

The first step in the process of vision is the conversion of light into signals that can be interpreted in the brain. This takes place in the retina, which is located in the back of the eye. Retina Definition The retina is the sensory membrane that lines the inner surface of the back of the eyeball. It's composed of several layers, including one that contains specialized cells called There are two types of photoreceptor cells in the human eye — rods and cones. Rod photoreceptors detect motion, provide black-and-white vision and function well in low light. Cones are responsible for central vision and Rods are located throughout the retina; cones are concentrated in a small central area of the retina called the macula. At the center of the macula is a small depression called the SEE RELATED: Retina Function Photoreceptor cells take light focused by the In the visual cortex of the brain (which, ironically, is located in the back of the brain), these signals are converted into images and visual perceptions. SEE RELATED: Retina Problems There is a wide variety of retina problems, conditions and diseases. Here is a short list of the more common retina problems: Macular degeneration. Age-related macular degeneration (AMD) is the most common serious, age-related eye disease, affecting 9.1 million Americans. And the prevalence of AMD — which affects one in 14 Americans over age 40 and more than 30 percent of seniors over age 75 — is increasing as the U.S. population continues to ag...

To understand the diseases and conditions that can affect the eye, it helps to understand basic eye anatomy. Here is a tour of the eye starting from the outside, going in through the front and working to the back. Eye Anatomy: Parts of the Eye Outside the Eyeball The eye sits in a protective bony socket called the orbit. Six The extraocular muscles are attached to the white part of the eye called the The layers of the tear film keep the front of the eye lubricated. The Front of the Eye Light is focused into the eye through the clear, dome-shaped front portion of the eye called the Behind the cornea is a fluid-filled space called the anterior chamber. The fluid is called Behind the anterior chamber is the eye’s Directly behind the pupil sits the By helping to focus light as it enters the eye, the cornea and the lens both play important roles in giving us clear vision. In fact, 70% of the eye's focusing power comes from the cornea and 30% from the lens. The Back of the Eye The vitreous cavity lies between the lens and the back of the eye. A jellylike substance called Light that is focused into the eye by the cornea and lens passes through the vitreous onto the A tiny but very specialized area of the retina called the The retina has special cells called The retina sends light as electrical impulses through the •