Sunday, April 6, 2008

7.31 Couching

The above is the cover page of a 17th Century reprint of one of the Chinese ophthalmology textbooks, written presumably by Sun Shi Ni (孫思邈) in 682AD. In which, a form of cataract surgery, known as couching with a golden needle (金针拨障术), was laid out in great detail.

During the Tang Dynasty (618-907AD), this technique was practiced by physicians from India. And it was apparently quite well-accepted. In fact, Poet Bai Ju Yi (白居易, 772-846) was known to mull over whether to have his cataracts treated medically or surgically:
(On my desk, there is this ophthalmology book,龙树论, next to it a box of pills, 决明丸. If the pills do not work, I'd have to go under the golden needle, 金蓖, quick.)

And around the same time, Philosopher Liu Yu Xi (刘禹锡, 772-842) wrote a thank-you poem to his cataract surgeon, a monk-ophthalmologist from India:
(Everything red is turning blue, I am now also photophobic and sensitive to the wind. Thank you for the couching needles, how that cut through my fogginess.)

Couching of cataracts with a needle was reported by a Hindu surgeon Susruta at around 5th Century BC. The triangular lancet (for corneal incision) and the couching needles are shown here:
You can almost find some similarities to modern-day instruments for ophthalmic surgery:
Is the procedure safe? Relatively speaking, yes. Wounds from, e.g., paracentesis (puncture of the peripheral cornea with a needle, usually to withdraw some aqueous humor), or small-incision cataract surgery rarely require sutures. The corneas self-heal. And if the cataractous lens stays in one piece, with little or no injuries to the iris or the ciliary body. The outcome can be quite favorable. However, in most cases, the complication rates can reach as high as 50%.

One might imagine that couching was performed under unsanitary conditions. By modern-day standards, most likely yes. Yet in the Synopsis of Ophthalmology (目经大成) compiled by Huang Ting Jin (黄庭镜) in 1774, the procedures listed eight steps. And the very first one called for a thorough cleansing of the surgical area around the eye.

In areas with no access to formally-trained surgeons and operating facilities, or for simple economical reasons, couching is still being practiced today. In a 2001 review of the surgical outcome of 1,274 eyes in a rural area of China, it was found that with proper post-op care, couching was no less efficacious than extra-cap surgery. In fact, the prevalence of blindness dropped from 5 to 2% and low vision from 24 to 6%. The key is then post-op care. However, in remote areas of, e.g., West Africa, couching as practiced by traditional healers, even the safety maybe compromised.

There is such a long Sino-Indian history of cataract couching. It is therefore mystifying to note a Yale-educated missionary doctor practicing in China, Peter Parker, MD (1804-1888), who wrote that

"Diseases of the eye were selected as those the most common in China [in the late Qing Era]; and being a class in which the native practitioners were most impotent, the cures, it was supposed, would be as much appreciated as any other."

And one of his more successful "cures" was none other than cataract couching, the very same technique practiced by Susruta and his followers throughout the ages, on different continents, and in many cultures including China.

To complete the discussion, couching can be either sharp (more common, with a needle) or blunt (by massaging the anterior portion of the cataractous eye). Blunt couching works only if the lens zonules are almost all disrupted.