Couching is the earliest documented form of cataract

Cataract

A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...

 surgery. As a cataract is a clouding in the lens of the eye, couching is a technique of dislodging the lens, thus removing the opacity. Although couching is no longer part of ophthalmic surgical practice, it was a precursor to modern cataract surgery

Phacoemulsification

Phacoemulsification refers to modern cataract surgery in which the eye's internal lens is emulsified with an ultrasonic handpiece and aspirated from the eye...

 and pars plana vitrectomy.

History

Records show that couching began at least by 600 BCE

Common Era

Common Era ,abbreviated as CE, is an alternative designation for the calendar era originally introduced by Dionysius Exiguus in the 6th century, traditionally identified with Anno Domini .Dates before the year 1 CE are indicated by the usage of BCE, short for Before the Common Era Common Era...

 in Mesopotamia

Mesopotamia

Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

, but may have existed in some form as early as 2000 BCE. After the 19th century CE, couching fell out of fashion, though it is still used in parts of Africa.

Modern use

Couching continues to be popular in some developing countries where modern surgery may difficult to access or where the population may prefer to rely on traditional treatments. It is commonly practiced in Sub-Saharan Africa

Sub-Saharan Africa

Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...

. In Mali

Mali

Mali , officially the Republic of Mali , is a landlocked country in Western Africa. Mali borders Algeria on the north, Niger on the east, Burkina Faso and the Côte d'Ivoire on the south, Guinea on the south-west, and Senegal and Mauritania on the west. Its size is just over 1,240,000 km² with...

 it remains more popular than modern cataract surgery, despite the fact that the cost of both methods is similar, but with much poorer outcome with couching. In Burkina Faso

Burkina Faso

Burkina Faso – also known by its short-form name Burkina – is a landlocked country in west Africa. It is surrounded by six countries: Mali to the north, Niger to the east, Benin to the southeast, Togo and Ghana to the south, and Côte d'Ivoire to the southwest.Its size is with an estimated...

, a majority of patients were unaware of the causes of cataracts and believed it to be due to fate

Destiny

Destiny or fate refers to a predetermined course of events. It may be conceived as a predetermined future, whether in general or of an individual...

. It is not performed by ophthalmologists, but rather by local healers or "witch doctor

Witch doctor

A witch doctor originally referred to a type of healer who treated ailments believed to be caused by witchcraft. It is currently used to refer to healers in some third world regions, who use traditional healing rather than contemporary medicine...

s".

Technique

A sharp instrument, such as a thorn or needle, is used to pierce the eye either at the edge of the cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

 or the sclera

Sclera

The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...

, near the limbus

Corneal limbus

The corneal limbus is the border of the cornea and the sclera . The limbus is a common site for the occurrence of corneal epithelial neoplasm....

. The opaque lens is pushed downwards, allowing light to enter the eye. Once the patients sees shapes or movement, the procedure is stopped. The patient is left aphakic

Aphakia

Aphakia is the absence of the lens of the eye, due to surgical removal, a perforating wound or ulcer, or congenital anomaly. It causes a loss of accommodation, hyperopia, and a deep anterior chamber. Complications include detachment of the vitreous or retina, and glaucoma.Aphakic people are...

 and therefore requires a powerful positive prescription lens to compensate.

Results

Couching is a largely unsuccessful technique with abysmal outcomes. A minority of patients may regain the ability to sense light and some movement, but over 70% are left totally blind. A Nigeria

Nigeria

Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

n study showed other complications include secondary glaucoma

Glaucoma

Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...

, hyphaema

Hyphema

Hyphema is blood in the front chamber of the eye. It may appear as a reddish tinge, or it may appear as a small pool of blood at the bottom of the iris or in the cornea.-Causes:...

, and optic atrophy. Couching does not compare favourably to modern cataract surgery.