Couching (ophthalmology)

For the embroidery technique, see Couching.

Couching is the earliest documented form of cataract 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 and pars plana vitrectomy.

History

Records show that couching began at least by 600 BCE in Mesopotamia, 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.^[1] In Mali 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.^[2] In Burkina Faso, a majority of patients were unaware of the causes of cataracts and believed it to be due to fate.^[1] It is not performed by ophthalmologists, but rather by local healers or "witch doctors".

Technique

A sharp instrument, such as a thorn or needle, is used to pierce the eye either at the edge of the cornea or the sclera, near the limbus. 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 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.^[2] A Nigerian study showed other complications include secondary glaucoma, hyphaema, and optic atrophy.^[3] Couching does not compare favourably to modern cataract surgery.

References

1. ^ ^{a b} Meda, N; Bognounou, V; Seni, E; Daboue, A; Sanfo, O (2005). "Cataract in Burkina Faso: Factors of choice between modern and traditional surgical procedures". Medecine tropicale 65 (5): 473–6. PMID 16465818. 
2. ^ ^{a b} Schémann, Jean-François; Bakayoko, Seydou; Coulibaly, Sidi (2000). "Traditional couching is not an effective alternative procedure for cataract surgery in Mali". Ophthalmic Epidemiology 7 (4): 271–83. doi:10.1076/opep.7.4.271.4174. PMID 11262674. 
3. ^ Omoti, AE (2005). "Complications of traditional couching in a Nigerian local population". West African journal of medicine 24 (1): 7–9. PMID 15909701.