An eyepatch is a small patch that is worn in front of one eye. It may be a cloth patch attached around the head by an elastic band or by a string, an adhesive bandage, or a plastic device which is clipped to a pair of glasses. It is often worn by people to cover a lost or injured eye, but it also has a therapeutic use in children for the treatment of amblyopia(See orthoptics and vision therapy). Eyepatches used to block light while sleeping are referred to as a sleep mask. Eyepatches associated with pirates are a stereotype originating from fiction.
An eyepad or eye pad is a soft medical dressing that can be applied over an eye to protect it. It is not necessarily the same as an eyepatch.
In the years before advanced medicine and surgery, eyepatches were common for people who had lost an eye. They were particularly prevalent among members of dangerous occupations, such as soldiers and sailors who could lose an eye in battle. While stereotypically associated with pirates, there is no evidence to suggest the historical accuracy of eye patch wearing pirates before several popular novels of the 19th century (see Pirate Eyepatches below).
Eye patching is used in the orthoptic management of children at risk of lazy eye (amblyopia), especially strabismic or anisometropic amblyopia. These conditions can cause visual suppression of areas of the dissimilar images by the brain such as to avoid diplopia, resulting in a loss of visual acuity in the suppressed eye and in extreme cases in blindness in an otherwise functional eye. Patching the good eye forces the amblyopic eye to function, thereby causing vision in that eye to be retained. It is important to perform “near activities” (such as reading or handiwork) when patched, thereby exercising active, attentive vision.
A study provided evidence that children treated for amblyopia with eye patching had lower self-perception of social acceptance. To prevent a child from being socially marginalized by his or her peers due to wearing an eye patch, atropine eye drops may be used instead. This induces temporary blurring in the treated eye.
A 2014 Cochrane Review sought to determine the effectiveness of occlusion treatment on patients with sensory deprivation amblyopia, however no trials were found eligible to be included in the review. However, it is suggested that good outcomes from occlusion treatment for sensory deprivation amblyopia rely on compliance with the treatment.
Extraocular muscle palsy
To initially relieve double vision (diplopia) caused by an extra-ocular muscle palsy, an eye care professional may recommend using an eyepatch. This can help to relieve the dizziness, vertigo and nausea that are associated with this form of double vision.
Use for adaptation to dark
1783 etching of wounded sailors
Rahmah ibn Jabir al-Jalahimah, once the most popular pirate in the Persian Gulf, was also the first to wear an eyepatch after losing an eye in battle. Although eyepatches have since become stereotypically associated with pirates, the source is unclear, and there is no historical evidence to suggest that their use was for any other reason than protecting and concealing the eye socket after the loss of an eye. Most historical depictions of seamen with eye patches are of ex-sailors, rather, than pirates.
More recent medical texts have often referred to the eye patch as a "pirate's patch" and writing in the Minnesota Academy of Sciences Journal in 1934, Charles Sheard of the Mayo foundation, pointed out that by "wearing a patch (The pirate's patch) over one eye, it will keep the covered eye in a state of readiness and adaptation for night vision". This technique was explored during WWII by institutes such as the United States Navy.
The proposal that pirates may have worn an eyepatch so that one eye would be pre-adjusted to below-deck darkness was tested in an episode of MythBusters in 2007 and found to be plausible, but without any recorded historical precedent.
Aircraft pilots used an eye patch, or close one eye to preserve night vision when there was disparity in the light intensity within or outside their aircraft, such as when flying at night over brightly lit cities, so that one eye could look out, and the other would be adjusted for the dim lighting of the cockpit to read unlit instruments and maps. Some military pilots have worn a lead-lined or gold-lined eyepatch, to protect against blindness in both eyes, in the event of a nuclear blast or laser weapon attack.
Eyepatches are not currently used by military personnel; modern technology has provided an array of other means to preserve and enhance night vision, including red-light and low-level white lights, and night vision devices.