The lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. The lens, by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as accommodation. Accommodation is similar to the focusing of a photographic camera via movement of its lenses. The lens is more flat on its anterior side than on its posterior side.
Far-sightedness, also known as hyperopia, is a condition of the eye in which light is focused behind, instead of on, the retina. This results in close objects appearing blurry, while far objects may appear normal. As the condition worsens, objects at all distances may be blurry. Other symptoms may include headaches and eye strain. People may also experience accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus.
Photophobia is a symptom of abnormal intolerance to visual perception of light. As a medical symptom, photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, though the term is sometimes additionally applied to abnormal or irrational fear of light such as heliophobia. The term photophobia comes from the Greek φῶς (phōs), meaning "light", and φόβος (phóbos), meaning "fear". Photophobia is a common symptom of visual snow.
A synechia is an eye condition where the iris adheres to either the cornea or lens. Synechiae can be caused by ocular trauma, iritis or iridocyclitis and may lead to certain types of glaucoma. It is sometimes visible on careful examination but usually more easily through an ophthalmoscope or slit-lamp.
The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The vitreous humor is produced in the non-pigmented portion of the ciliary body. The ciliary body is part of the uvea, the layer of tissue that delivers oxygen and nutrients to the eye tissues. The ciliary body joins the ora serrata of the choroid to the root of the iris.
The human eye is an organ which reacts to light and pressure. As a sense organ, the mammalian eye allows vision. Human eyes help to provide a three dimensional, moving image, normally coloured in daylight. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth. The human eye can differentiate between about 10 million colors and is possibly capable of detecting a single photon.
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. 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.
The ciliary muscle is a ring of smooth muscle in the eye's middle layer that controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humor into Schlemm's canal. It changes the shape of the lens within the eye, not the size of the pupil which is carried out by the sphincter pupillae muscle and dilator pupillae.
The European Squadron, also known as the European Station, was a part of the United States Navy in the late 19th century and the early 1900s. The squadron was originally named the Mediterranean Squadron and renamed following the American Civil War. In 1905, the squadron was absorbed into the North Atlantic Fleet.
An iridectomy, also known as a surgical iridectomy or corectomy, is the surgical removal of part of the iris. These procedures are most frequently performed in the treatment of closed-angle glaucoma and iris melanoma.
The anterior segment or anterior cavity is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens.
The word geek is a slang term originally used to describe eccentric or non-mainstream people; in current use, the word typically connotes an expert or enthusiast or a person obsessed with a hobby or intellectual pursuit, with a general pejorative meaning of a "peculiar person, especially one who is perceived to be overly intellectual, unfashionable, boring, or socially awkward".
A circle contact lens, also known as a big eye contact lens and circle lens, is a cosmetic contact lens that makes the eye's iris appear larger. It has become a trend throughout East, South and Southeast Asia and is largely produced in Japan, South Korea and China.
USS Iris was a ship of the United States Navy which served in the Pacific in a variety of roles from 1899 until 1916. Originally fitted out as a distilling ship, she served as a general utility ship, then as a collier, before being refitted as a torpedo boat tender.
Phacodonesis is the tremulousness or vibration of the lens with eye movement. This is often due to lens subluxation, the incomplete or partial dislocation of the lens, caused by an injury to the eye in which some or most of the zonular fibers are broken. The term originated from phaco- + doneo.
Google Contact Lens is a smart contact lens project announced by Google on 16 January 2014. The project aims to assist people with diabetes by constantly measuring the glucose levels in their tears. The project was being carried out by Verily and as of 2014 was being tested using prototypes. On November 16, 2018, Verily announced it has discontinued the project.
