Eyepatch

A child wearing an adhesive eyepatch to correct amblyopia

An eyepatch or eye pad 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.

History

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, as well as blacksmiths who used them to cover one eye for protection from sparks while working.^[1] While stereotypically associated with pirates, there is no evidence to suggest the historicity of eye patch wearing pirates before several popular novels of the 19th century (see Pirate Eyepatches below).

Eyecare treatment

Amblyopia

Eye patching is used in the orthoptic management^[2] of children at risk of lazy eye (amblyopia), especially strabismic or anisometropic^[3] amblyopia. These conditions can cause visual suppression of areas of the dissimilar images^[4] 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.^[2][3]

A study provided evidence that children treated for amblyopia with eye patching had lower self-perception of social acceptance.^[5] To avoid a child from being socially marginalized by its peers due to the wearing of an eye patch, atropine eye drops may be used instead. This induces temporary blurring in the treated eye.

It has been pointed out that the penalization of one eye by means of patching or atropine drops does not provide the conditions that are necessary in order to develop or improve binocular vision. Recently, efforts have been made to propose alternative treatments of amblyopia that do allow for the improvement of binocular sight, for example using binasal occlusion or partially frosted spectacles^[4] in place of any eye patch, using alternating occlusion goggles or using methods of perceptual learning based on video games or virtual reality games for enhancing binocular vision.

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.^[6][7][8]

Use for adaptation to dark

Aircraft pilots

Aircraft pilots used to use 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.^[9] The FAA still recommends, "a pilot should close one eye when using a light to preserve some degree of night vision".^[10] 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.^[11][12][13]

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.^[14][15][16]

Pirates

Stereotypical depiction of a pirate with eyepatch

It is a stereotype that pirates during the age of sail often wore eyepatches. This stereotype is common in fiction and was popularized by the novel Treasure Island.

Whilst piracy was a violent occupation and eye injuries occurred, a myth supposes that pirates wore a patch over one of their eyes to adjust that eye to darkness in preparation for battle. That way, when they boarded a ship and were ready to go below deck, they could remove their patch and be able to see well in the poorly lit interior of the ship. It takes time for the eye to adjust itself for darkness – had they not prepared their eye ahead of time by using an eyepatch, the boarders would have been at an immediate tactical disadvantage the moment they went below.^[17]

Although the idea is plausible, this tactic does not appear in any naval combat manual or historical account of the era.^[17]

Sea sickness and eye patches

It has been suggested that eye patches can help with sea sickness, is the same thing as motion sickness, except that it takes place on a sea or another large body of water, such as an ocean or a lake. But this refers to covering both eyes with a sleep mask or similar device. It is generally accepted that keeping both eyes open and focusing on the distant horizon is more effective, since sea sickness results from the sensory inputs of the eyes and the vestibular senses.

Notable eyepatch-wearers

See also

• Orthoptist
• Haploscope
• Diplopia
• Binocular vision
• Stereopsis

References

External links

• International Orthoptic Association