Human Eye Diagrams

Members of the animal kingdom use different strategies to detect light and focus it to create images. Human eyes are “camera-type eyes,” this means they work like camera lenses focusing light onto film.
Posterior chamber is an important structure involved in production and circulation of a watery fluid known as the aqueous humor, or aqueous. It is circular in form, and allows light to pass through onto the lens. Just like the aperture of a camera, it controls the number of light that goes into. In bright environments, the pupil of the attention constricts, while in dark environments, it dilates. The iris includes a ring of muscle fibers around the pupil, which, when they contract, causes the pupil to constrict . The second group of muscle fibers radiate outward from the pupil.

• Glaucoma is one of the most common eye conditions linked to optic nerve damage.
• ends of the nasolacrimal ducts, which carry the tears into the nose.
• Because you can find no rods and cones, it is also referred to as the blind spot.
• About 15° temporal and 1.5° below the horizontal is the blind spot developed by the optic nerve nasally, which is roughly 7.5° high and 5.5° wide.

The conjunctiva contains visible blood vessels that are visible against the white background of the sclera. The light-sensitive tissue lining at the back of the eye. The retina converts light into electrical impulses which are sent to the brain through the optic nerve. The lids moisten the attention each time we blink plus they close as a reflex action so that you can protect against the wind, liquids and foreign bodies. Typically, people blink eight to twelve times a minute, which spreads tear fluid across the surface of the attention in fractions of a second. The cornea is densely populated with nerve endings and incredibly sensitive.
This occurs under reduced illumination or in darkness. The eyelids serve to protect the attention from foreign matter, such as dust, dirt, and other debris, as well as bright light that might damage the eye. When you blink, the eyelids also help spread tears over the surface of one’s eye, keeping the attention moist and comfortable. The orbit also includes the lacrimal gland that’s located within the outer portion of the upper eyelid.

Anatomy And Physiology Of The Attention

The puncta are openings into the lacrimal ducts; these carry the tears in to the lacrimal sacs, the dilated upper ends of the nasolacrimal ducts, which carry the tears in to the nose.
The lens is transparent, and may be replaced if necessary. Our lens deteriorates as we age, resulting in the necessity for reading glasses. Intraocular lenses are used to replace lenses clouded by cataracts. Layer containing arteries that lines the trunk of the attention and is located between the retina (the inner light-sensitive layer) and the sclera . The tear gland located above each eyeball and within your upper eyelid.

It is induced when the entire visual scene drifts across the retina, eliciting eye rotation in the same direction and at a velocity that minimizes the motion of the image on the retina. When the gaze direction deviates too much from the forward heading, a compensatory saccade is induced to reset the gaze to the centre of the visual field. This tracking is less accurate compared to the vestibulo-ocular reflex, as it requires the mind to process incoming visual information and supply feedback. Following an object moving at constant speed is relatively easy, though the eyes will often make saccades to keep up. The smooth pursuit movement can move the eye at up to 100°/s in adult humans.

Pupil: Aperture Of The Attention

The process of dilatation and constriction of pupil isn’t instantaneous. The macula is located in the central area of the retina and has the highest concentration of cones.

Ducts from each gland, three to 12 in number, open into the superior conjunctival fornix, or sac. From the fornix, the tears flow down across the eye and in to the puncta lacrimalia, small openings at the margin of each eyelid near its inner corner.

The front surface of the optic nerve, which is visible on the retina, is called the optic disk or optic nerve head. The conjunctiva is a thin, transparent layer of tissues within the front of the eye, like the sclera and the inside of the eyelids. The conjunctiva keeps bacteria and foreign material from getting behind the attention.