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    The lens of the eye is like an adjustable lens of a camera and focuses light rays on to the retina for sharp images. A condition called presbyopia occurs when the lens is no longer able to adjust for objects at different distances.


The lens of the eye is like an adjustable lens of a camera and focuses light rays on to the retina for sharp images. A condition called presbyopia occurs when the lens is no longer able to adjust for objects at different distances.

A membrane lining the inside of the back of the eye that contains light-sensitive nerve cells that convert focused light into nerve impulses, making vision possible.

The term "condition" has a number of biomedical meanings including the following: 1.An unhealthy state, such as in "this is a progressive condition." 2.A state of fitness, such as "getting into condition." 3.Something that is essential to the occurrence of something else; essentially a "precondition." 4.As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

The eye's gradually decreasing ability to focus on nearby objects. Presbyopia is a normal part of aging and affects virtually everyone, usually becoming noticeable after age 40. People with presbyopia typically hold reading materials at arm's length in order to bring the words into focus. They may experience headaches or eyestrain while reading, viewing a computer screen, or doing close work. Presbyopia can be corrected with reading glasses, bifocal or variable focus lenses, or contact lenses. Using bright, direct light when reading is also helpful.

The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.



Levitra, based in vardenafil, is Bayer's selective product for the treatment of erectile dysfunction.

Lacrimal gland
The tear gland located under the upper eyelid at the outer corner of the eye. The fluid it secretes cleans and provides moisture for the cornea. It is responsible for tearing during emotional stimulation or following corneal irritation by a foreign body or chemical.

Lacrimal sac
The tear sac located on the side of the nose adjacent to the inner corner of the eye. Tears normally drain from the eye into the tear duct and then through the sac, finally leaving by a drain which enters the nose. The tear sac remains filled with tears when an infant has a blocked tear duct. An infection of the tear sac is called a dacryocystitis.

LASIK (Laser in-Situ Keratomileusis) combines the precision of the excimer laser delivery system with the benefits of Lamellar Keratoplasty (LK) which has been proven to treat a wide range of refractive errors. Using the accuracy and precision of the excimer laser, LASIK changes the shape of the cornea to improve the way light is focused or "refracted" by the eye. First, a thin corneal flap is created, as an instrument called a microkeratome glides across the cornea. Then, in just seconds, ultraviolet light and high energy pulses from the excimer laser reshape the internal cornea with accuracy up to 0.25 microns. By adjusting the pattern of the laser beam, it is possible to treat high levels of nearsightedness and moderate amounts of farsightedness and astigmatism.

Lazy eye
A term often used instead of amblyopia. A loss of visual function, usually measured by visual acuity, in one or both eyes that cannot be explained by identifiable causes(s) such as a cataract or retinal disease. An eye that turns in (esotropia) or out (exotropia) may have a certain degree of central visual loss (amblyopia). A lazy eye is often treated by placing a patch over the stronger eye and forcing use of the lazy eye. The earlier the detection of the lazy eye the better for recovery of central vision with patching. If left untreated, after the age of about 8 or 9 years, patching therapy is no longer effective and the child will have a permanent loss of vision and loss of binocular vision and depth perception.


Lens capsule
The lens capsule is a membrane that surrounds the lens of the eye. In cataract surgery, the lens is usually replaced with an intraocular lens but the lens capsule remains in the eye.

An antipsychotic drug.

Legionnaire disease
An acute, sometimes fatal, pneumonia-like bacterial infection characterized by high fever, malaise, muscle aches, respiratory disorders and headache. It is named for an outbreak at the 1976 Philadelphia convention of the American Legion

Leber's disease

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