合成视觉有望让盲人复明

    50多年前，当乔治斯还是个18岁的小伙子时，不幸患上了色素性视网膜炎。他被告知视力将逐渐退化，直至全盲。不出所料，到了50多岁时，他的世界变得完全漆黑一片。但是去年，就在一个按钮被按下的瞬间，乔治斯突然重新见到了光明。他惊呼道：“当他们通上电以后，感觉真的就像烟花表演一样。”

    这款神奇的产品名叫Iris系统，旨在帮助盲人恢复视力。它是由一家名叫Pixium Vision，成立没多久的法国企业开发的，乔治斯正是首批试验该设备的病人之一。该公司的创始人伯纳德•吉利原本是一位科学家，旗下拥有多家致力于利用科技（大多围绕神经系统）改善人体健康的企业。

    吉利指出：“眼科是研究人体中枢视经系统的一个好途径，因为眼睛、特别是视网膜，就像是大脑的一个可见部分。”他指出，法国有约20万人处于全盲或接近全盲，而且基本上是没法治愈的。“很多人不了解这种情况有多普遍，这是因为我们在街上看不到很多盲人，因为他们在室外容易发生事故，所以他们倾向于待在家里。”

    吉利表示，微生物学与微电子学等领域的技术进步，为盲人复明带来了新的希望。另外科学家也付出了大量努力来理解大脑的工作机制。我们很久以前就知道电流可以刺激人的神经系统，另外，我们已经开始使用一种叫做“神经调节”的技术来治疗帕金森症和各种慢性疼痛。现在，这项技术也能治疗眼盲了。

    最适合使用Iris的是那些患有退化性眼病的患者。医生向患者的视网膜内植入一块带有150个电极的微小芯片。手术后，患者需要戴上一副专用的墨镜，其中的集成摄像机可以向一台微型便携电脑传送图像。这台电脑随后把图像转换成数字信号，回传到墨镜上，然后再无线传输至植入芯片的接收器上。电子脉冲会激活电极，人的视神经便会将图像传送到大脑。

    在接受手术后，患者需要参加一个康复项目，以教会他们的大脑如何解读这些新的图像。他们所见到的只是一些黑白灰色的基本形状。（这套解决方案目前尚不能让患者重新阅读或识别面部特征。）

    亚尼克•拉•梅尔已经将这套系统植入三名测试者的眼球中。他表示：“我们没有让他们重获视力，但提供了另一种让他们看见的办法。”拉•梅尔表示，目前无法知道每名患者的反应如何，因为它取决于每个大脑的适应性——就像学钢琴或学日语一样，有的人学得很快，但也有人学得非常慢。

    More than half a century ago, when he was just 18 years old, Georges* learned that he had retinitis pigmentosa. He was told that his vision would progressively deteriorate until he was blind. As predicted, when Georges reached his early fifties, his world went completely dark. Last year, at the push of a button, Georges suddenly saw light again. “When they got the electrodes going, it was a real fireworks show,” he exclaims.

    Georges is part of a pilot program testing Iris, a product to restore vision to blind people, made by a young French company called Pixium Vision. The company’s founder, Bernard Gilly, is a scientist-turned-entrepreneur with a network of businesses focused on using technologies to improve human health, mostly around the nervous system.

    “Ophthalmology seemed like a good way to approach the central nervous system because the eye, and especially the retina, is like a visible part of the brain,” Gilly says, noting that France counts 200,000 people in the country who are blind or nearly blind, and that generally there is no cure. “People are unaware of how prevalent the condition is because there are not many blind people in the streets. They are more prone to accidents, so they tend to stay home.”

    Technological advances such as microbiology and microelectronics are creating new opportunities to restore sight, Gilly says, and scientists are making enormous strides in understanding the workings of the brain. It’s long been known that electricity can stimulate the nervous system, and a technique called “neuromodulation” is being used to address everything from Parkinson’s disease to chronic pain. Now, it can treat blindness, too.

    The best candidates for Iris are patients with degenerative eye conditions. A surgeon implants a tiny silicon chip with 150 electrodes on the retina. Afterwards, the patient wears a pair of dark glasses with an integrated video camera that sends images to a portable mini-computer. This computer transforms the pictures into digital signals, which are sent back to the glasses, then transmitted wirelessly to a receiver on the implant. Pulses activate the electrodes, and the optic nerve carries the images to the brain.

    After surgery, patients follow a program of rehabilitation to teach their brains how to interpret these new images. What they see is basic shapes in variations of black, white, and gray. (The resolution is still too low for them to distinguish facial features or read.)

    “We don’t give them back their sight, but another way of seeing,” says Yannick Le Mer, the surgeon who implanted the system in three of Pixium’s test subjects. Le Mer says it is impossible to know beforehand how anyone will react, since it depends on each brain’s adaptability—like learning to play the piano or speak Japanese. Some catch on immediately, while others struggle.