20/20 vision is a term used to describe normal visual clarity or sharpness measured at a 20 foot distance. If you have 20/20 vision, you can clearly see everything you are supposed to see at a 20 foot distance. If you have 20/100 vision, you must be at a 20-foot distance in order to see what someone with 20/20 vision can see at 100 feet. 20/20 vision does not mean perfect vision; it’s just the clarity of vision at a distance.
Nearsightedness (myopia) is a visual condition occurring when you can see close objects clearly but cannot see distant ones.
Farsightedness (hyperopia) is a visual condition occurring when you can see distant objects clearly, but close objects are difficult to bring into focus.
Astigmatism is a visual condition in which objects at all distances can appear blurred because light entering the eye is unable to be brought into focus.
A cataract occurs when the normally clear lens within your eye becomes cloudy. Cataracts vary from a very small cloudy area to large opaque areas causing a loss of vision. Cataracts usually occur in persons over the age of 55 and rarely in younger people including newborns. Cataracts are usually caused by chemical changes occurring in your eye; but are sometimes caused by excessive exposure to sunlight, cigarette smoking, certain medications, etc. A doctor can determine if you have a cataract forming.
Glaucoma is a disease in which the fluid pressure in the eye increases and damages the optic nerve, often resulting in severe vision loss.
Macular degeneration is an eye disease that occurs when there are changes to the macula (a small portion of the retina that is located on the inside back layer of the eye). It limits central vision and makes seeing objects and details straight ahead difficult or impossible. It is the leading cause of vision loss among people over the age of 50. Macular degeneration is caused either by the tissue of the macular gradually becoming thinner and stops operating properly, or when fluids leak from newly formed blood vessels under the macula and blur central vision. If you experience any gradual vision loss, contact your doctor immediately.
Diabetes is a disease that prevents your body from producing insulin to break down sugar, thereby resulting in high levels of sugar in the blood. It can cause changes in nearsightedness, farsightedness, and premature presbyopia. This can result in cataracts, glaucoma, strabismus, and decreased corneal sensitivity. Visual symptoms include blurred vision, double vision, night vision problems along with others. The most serious eye problem is retinopathy which occurs when there is a weakening or swelling of the tiny blood vessels in the retina of your eye. Retinopathy causes blood leakage, the growth of new blood vessels, and other difficulties. If it is left untreated, retinopathy could result in blindness.
Eye coordination is the ability of both of your eyes to work together. Each eye sees a slightly different image, and the brain blends the two images together into one three-dimensional picture. Poor eye coordination results from a lack of adequate vision development or improperly developed muscle control. Since poor eye coordination can be difficult to detect, periodic eye exams starting at the age of 6 months are recommended.
Conjunctivitis is an inflammation of the conjunctiva (the thin transparent layer covering the surface of the inner eyelid and a portion of the front of the eye. This occurs in many forms and affects people of all ages. The three main forms of conjunctivitis are infectious (commonly known as “pink eye” and caused by a contagious virus or bacteria), allergic (caused by your body’s allergies) and chemical (caused by irritants such as pollution in the air, noxious fumes or chlorine). Common symptoms of conjunctivitis are red eyes, inflamed inner eyelids, watery eyes, blurred vision, a sandy or scratchy feeling in the eyes, and discharge around the eyelids.
Dry eye occurs when your eyes cannot produce enough tears or produce tears which do not have the proper chemical composition necessary for overall eye health and clear vision. The most common symptoms include stinging, itchy, scratchy, burning and uncomfortable eyes.
Sight disorders are the fourth most common disability and most prevalent impeding condition found in children. Of 74 million children only 14 percent have had a vision evaluation by the age of five. It is extremely important to get their eyes checked every year starting at the age of six months. Twenty percent of school-aged children have a learning disability of which 70 percent of these have some degree of vision impairment. Premium polycarbonate lenses treated with scratch-resistant coating and ultraviolet filters are recommended for children who use computers, play video games or watch television. Many designers are lending their names to ophthalmic eyewear and sun-wear collections so that children who need glasses can still be "cool".