The epicanthal fold, an extra skin fold that covers the inner corner of the eye, can be a normal trait in infants of East Asian or Native American descent. They inherit the fold, which gives the eye an almond-shaped appearance, from their parents.

Hard contact lenses, also known as Rigid Gas Permeable lenses, are made of a hard plastic that allow oxygen to reach your eyes. Hard contacts do a better job of correcting some vision problems than soft lenses.

According to Refractive Error Source, it is common to have some degree of imperfect vision because light does not focus correctly on most people's retinas. Most vision issues can be corrected with eyeglasses.

Bifocals began when Benjamin Franklin had the lenses of two different spectacles cut in half and wired into a single frame. As technology has advanced, more complex lens configurations were created, with multiple areas of magnification, called segments, cut into the same lens.

Eye lesions may gradually increase in size, though it may take the lesions a number of years before they reach a noticeable size. Most lesions cause surface irritation, resulting in constant redness and discomfort.

Blurry vision and dizziness often occur together because of the complex relationships between visual processing and other organ systems of the body.

Though seeing dark circles and squiggles in front of your eyes isn't pleasant, it usually isn't harmful either. Rather, eye floaters are often a natural yet irritating part of aging, and the best way to treat them is to do your best to ignore the visual disturbances.

Bifocals are the most common type of multi-focal prescribed for people over 40, according to the Cleveland Clinic. Bifocal fit and placement is an essential part of a person's eyeglass prescription.

Xylene is a powerful chemical compound that is found in many household and industrial items. This chemical is colorless but has a very distinctive odor. Products that contain xylene include paints, varnishes, fingernail polish, adhesives, rubber cement and gasoline.

Approximately 33 million Americans experience dry eye symptoms, including dryness, irritation, burning and grittiness, according to VisionWorksUSA.com. Dry eye is directly related to the underlying health condition of the entire body, according to Dr. Marc Grossman, O.D.

Red, puffy eyes are uncomfortable to have and painful to look at. Sometimes the condition is accompanied by mild irritation, while other times your eyes may swell up to the size of lemons.

Bifocal lenses take some adjustment for many people, whether you start with bifocals or switch from regular lenses. New bifocal wearers might experience difficulty as they move from looking through the top to the bottom of the lenses.