望遠隱形眼鏡——失明患者的福音

Lights， mirrors， action！ Scientists are developing smart contact lenses 1）embedded with 2）miniscule mirrors that can magnify your vision by almost three times.

The 1.55mm-thick lenses 3）incorporate a thin reflective telescope made of mirrors and 4）filters； when light enters the eye it bounces off the series of mirrors and increases the perceived view of an object or person. It is hoped that the lens will improve the sight of people with age-related 5）macular 6）degeneration （AMD）—the third leading cause of blindness globally.

AMD causes the loss of central vision due to gradual damage to the eye’s 7）retina and there are few options for cure or treatment. “AMD is the biggest problem where 8）magnification is a proven visual aid，” says Eric Tremblay， research scientist at 9）EPFL in Switzerland.

Tremblay led the 10）optical design of the lens， which is based on a surgically implantable telescope currently used by some patients with AMD， but which is more 11）invasive than a lens. “With a contact lens， it’s easy to try it，” says Tremblay.

Making the Switch

A key innovation with the lenses is the added ability to switch between magnified and regular vision through a complementary pair of glasses. The battery-powered glasses use LCD technology to watch the movement of the eye and a simple wink can alter their 12）polarization and determine whether light entering is magnified or not.“Having the ability to switch on demand is attractive，” says Tremblay.

The ability to selectively magnify your vision makes the design of the glass-lens combination more suitable for daily life. “When magnified you lose a lot of your field of view， your 13）peripheral vision，” says Tremblay. A strategic wink will enable users to keep an eye on their periphery， such as cars approaching them as they cross a street， whilst also being able to 14）zoom in and recognize the faces of those around them.

The team developed their technology on 15）scleral lenses， which have an increased thickness and 16）diameter， making them commonly used for more special purpose eye care. “They provide a lot more area to work with，”says Tremblay. The challenge these lenses bring with them， however， is comfort， as they 17）impede the amount of oxygen reaching the eye.

The most recent 18）prototype， unveiled by the team in February， overcame this challenge by introducing air channels to aid the flow of oxygen to the eye. But the team hopes to improve this further still by instead developing a contact lens solution 19）saturated with oxygen， which can be stored and slowly released into the eye. “We will build 20）reservoirs into the back of the lens，” says Tremblay.

The lenses have only been trialled on a handful of humans to test for comfort， with the majority of research to date performed in the lab using a model chemical eye. But more human trials are 21）in the cards， with the eventual goal of daily wearable contacts to aid the visually impaired.

“We want it to move in the direction of a real world vision aid，” says Tremblay.

Getting Smarter

These are not the first smart contact lenses. Other prototypes have been developed to monitor， as well as improve， health in both the eye and across the body.

Alcon， the eye care division of 22）Novartis， formed a partnership with 23）Google X in 2014 to develop smart-lens technologies for a range of medical eye care applications. One of the first examples of using lenses in this form was 24）Sensimed， a 25）spin-off also emerging from EPFL. Sensimed’s Triggerfish technology monitors the progression of 26）glaucoma—the second leading cause of blindness， affecting more than 4.5 million people globally.

Glaucoma is a progressive cause of blindness caused by 27）deterioration of the eye’s optic nerve. The traditional test used by 28）optometrists to monitor patients uses 29）puffs of air to measure pressure in the eye， but such measurements are not ideal.

“The big need in glaucoma is for a 24-hour picture of what’s happening inside the eye，” says David Bailey， CEO of Sensimed. Its smart lens uses 30）strain gauges and 31）sensors embedded inside a chip located in the lens to measure changes in the volume of liquid in the eye as a 32）surrogate measurement of pressure. It can be worn over a 24-hour period to monitor pressure patterns and communicate data wirelessly to a recording device worn around the user’s neck.

Optometrist James Wolffsohn， spokesperson for the British Contact Lens Association， looks forward to one day using technologies like the 33）telescopic lens in 34）clinical practice.“The lens seems an interesting concept to provide optical magnification to the retina when required，” he says. But he adds that there will be challenges in reaching that stage： “It is currently a scleral lens and thick， including 35）rigid mirror elements which are likely to affect 36）corneal 37）physiology and comfort.” Wolffsohn has seen colleagues trial the more established Triggerfish technology to monitor glaucoma， and is optimistic about the future of the field. “There are also many other exciting developments in innovative uses of contact lenses，” he says.

“The eye is the window to many disease states，” says Bailey， who believes contact lenses are the future for eye care， both in terms of clinical use and lifestyle management. More than 30 million people wear contact lenses in the United States alone， according to the Centers for Disease Control， which means they could be a non-invasive path to health management—be it blindness progression or even 38）insulin or alcohol level monitoring.

“Eye-sensing on contact lenses is here to stay...in one form or another，” says Bailey.

光線，鏡片，行動！科學家目前正在研發一種置入細微鏡片的智能隱形眼鏡，它能把視覺成像放大將近三倍。

這1.55毫米厚的鏡片包含了由鏡面和濾光鏡組合而成的一片薄薄的反射望遠鏡；當光線進入眼睛，這幾層鏡片會對其作出折射，增強眼睛對物體或人的感知。老年性黃斑變性是導致失明的全球第三大禍根，而這種隱形眼鏡有望改善該病患者的視力。

老年性黃斑變性會逐步損害視網膜，進而導致中心視力喪失，而現有的藥物和治療方案屈指可數。“老年性黃斑變性是最大的難題，已知的視覺輔助解決手段就是放大（視覺成像）。”瑞士洛桑聯邦理工學院的科學家埃里克·特萊姆布雷說道。

特萊姆布雷帶領團隊完成了這種望遠隱形眼鏡的光學設計。目前一些老年性黃斑變性患者通過外科手術把望遠鏡鏡片植入到眼球中，望遠隱形眼鏡的光學設計以這種手術為基礎，但比外科手術少了侵入性。特萊姆布雷說：“通過隱形眼鏡的形式，人們想要嘗試就容易了。”

開發切換功能

望遠隱形眼鏡的主要創新之處就是配上一副框架眼鏡來增加切換放大視野和常規視野的功能。這副框架眼鏡由電池提供動力，采用液晶顯示技術來監測眼球的動態，簡單的一次眨眼就能更改光的偏振狀態，決定進入的光線是否放大。“按需切換功能很吸引人。”特萊姆布雷說道。

選擇性放大視覺成像的功能讓這種結合框架眼鏡和隱形眼鏡的設計更適應日常使用。……