Where did eye patches originate? You'd probably guess it was an early and low-tech way to conceal an unsightly eye injury. While this may be partially true it is more likely that patches were first used by individuals with two perfectly good eyes. There is speculation that sailors, in order to keep one eye adjusted to seeing in the darkness below deck, used an eye patch. Whether scurrying below deck to modify rigging or reloading weapons, keeping one eye adapted to seeing in low levels of light could save a valuable few minutes in a crucial situation.
Today eye patches are typically used as costume pieces or to protect an injured eye. Research has brought us a variety of innovative treatments for eye maladies, but many visual problems are caused by injury. Here are some of the most common injuries - some of which may earn you an eye patch:
Corneal Abrasion: A corneal abrasion is essentially a scratch on the transparent covering of the eye. Abrasions can occur from walking into foreign objects such as hanging tree branches, or by rubbing the eye when something like dust or sand is present. Abrasions are usually minor but the risk of infection from bacteria can be a serious threat. Antibiotic eye drops and a topical pain reliever is the most common treatment.
Chemical exposure: Being splashed by anything but clean water is a risk to the eyes. Many acids, such as vinegar, lemon juice, and some shampoos, may cause significant redness and burning, but can be washed out with no real damage. Chemicals that are basic (a pH over 7) such as bleach, ammonia, or lye, are a more serious threat but may not seem so as many do not cause immediate eye pain or redness. As soon as possible after exposure the eye should be flushed with warm tap water for 15 minutes. Long term treatment depends on the type of chemical exposure and if tissue damage occurred.
Swelling: What do moving baseballs, flying fists, bathroom sinks, and stepping on a rake have in common? They all can result in some mean black eyes. Being struck in the eye with just about anything causes swelling followed by discoloration. The swelling is the result of simple tissue inflammation, whereas the discoloration is due to swollen or ruptured blood vessels. The best treatment is to put an ice pack over the affected area to reduce swelling. Despite being an old wives tale, placing a steak or a pork chop on a black eye is not an effective treatment.
Eye bruising/bleeding: Being struck in the vicinity of the eye often causes the small, delicate blood vessels under the whites of the eyes to break and discolor the eye. This is called a subconjunctival hemorrhage and looks much worse than it actually is. It is quite common and despite its dramatic appearance, actually poses little risk of any long term visual or cosmetic damage. Other than looking scary for 7 to 10 days and waiting for the blood vessels to heal themselves there is not much of a treatment for this condition. Over time the blood clears on its own and the eye returns to normal appearance.
For more information about eye injuries the National Institutes of Health has a good online resource. This 4th of July be sure to keep the bottle rockets aimed away from your face.