The most common cause of eyesight problems is likely genetics. Some people are simply more prone than others to problems with their eyes. Damage to the eyes, on the other hand, is commonly caused by overuse, trauma, and disease. Depending on the problem, the disorder could be linked to any number of causes, so it is a good idea to figure out the specific components of the eyesight problems before seeking a diagnosis. Once the problem has been identified further, the causes can be more readily identified.
People who are either nearsighted or farsighted often have a family member with the disorder. Nearsightedness, sometimes called myopia, is usually related to family history, but sometimes can be attributed to long-term use of a computer or performing other close-up work. Farsightedness, or hyperopia, is also usually related to family history, but can begin later in life as a result of aging.
Eyesight problems like glaucoma are usually caused by fluids in the eye failing to drain. This failure to drain is sometimes related to a specific disorder, such as diabetes or tumors, but it is just as often related to old age. Similarly, eyesight problems such as cataracts can be caused by diseases, but are usually an effect of aging. Cataracts are the result of degradation of proteins in the eye, but when these eyesight problems are caused by exposure to ultra-violet light, smoking, or use of steroids, they can occur at a young age as well.
Sometimes eyesight problems can be caused by trauma to the eye. A black eye, for instance, can disrupt vision, as can an eye infection. Sometimes the problem is as simple as flashing or blurry vision. When trauma is severe, sight in the affected eye can be lost completely. It is important to thoroughly investigate any eyesight problems related to trauma because the problem may be in the brain, not specifically in the eye.
In addition to these more serious vision problems, many people experience minor problems with eyesight from very basic causes. Being awake for an excessive amount of time, for example, can cause vision to blur, and dirty or old contact lenses can cause distortions in vision. Allergies often result in dry eyes, as does pregnancy for some people, and sometimes dust or other irritants in the air can cause the eyes to water. Before investigating rarer causes for these very basic, fairly harmless vision problems, it is a good idea to rule out the obvious causes first.