首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Famed singer Stevie Wonder can’t see his fans dancing at his concerts. He can’t see the hands of his audience as they applaud wi
Famed singer Stevie Wonder can’t see his fans dancing at his concerts. He can’t see the hands of his audience as they applaud wi
admin
2011-05-29
43
问题
Famed singer Stevie Wonder can’t see his fans dancing at his concerts. He can’t see the hands of his audience as they applaud wildly at the end of his Superstition.
Blind from birth, Wonder has waited his whole life for a chance to see. Recently, Wonder visited Mark Hamayan, a vision specialist. He thought that a new device currently being studied by Humayan might offer him that chance.
The device, a retinal prosthesis, is a tiny computer chip implanted inside a patient’s eye. The chip sends images to the brain and allows some sightless people to see shapes and colors. Wonder hoped the retinal prosthesis might work for him. "I’ve always said that if ever there’s possibility of my seeing," said Wonder, "then I would take the challenge."
Unfortunately for Wonder, that challenge will have to wait. Humayan explained that the device isn’t ready for people who have been blind since birth. Their brains may not be able to handle signals from a retinal prosthesis because their brains have never handled signals from a healthy eye.
The retinal prosthesis and other devices, however, show great promise in helping many other sightless people who once had vision see again. Perhaps one day soon, some formerly sightless people may be in Wonder’s audience looking up—and seeing him—for the very first time.
Wonder’s willingness to take part in retinal prosthesis studies and the results of those studies are giving new hope to people who thought they would be blind for the rest of their lives. More than one million people in the United States are considered legally blind, meaning that their eyesight is severely impaired. Another one million are totally blind.
Two types of specialized cells in the retina—rods and cones—are critical for proper vision. Light enters the eye and falls on the rods and cones in the retina. Those cells convert the light to electrical signals which travel through the optic nerve to the brain. The brain interprets those signals as visual images. Rods detect light at low levels of illumination. For instance, rods allow you to see faint shadows in dim moonlight. Cones, on the other hand, are most sensitive to color. Some diseases can damage cells in the retina. For instance, macular degeneration causes blindness and other vision problems in 700,000 people in the United States each year. The condition is caused by a lack of adequate blood supply to the central part of the retina. Without blood, the rods, cones, and other cells in the retina die.
Devices such as the retinal prostheses won’t prevent or cure our eye diseases, but they may help patients who have eye disorders regain some of their vision. Different forms of retinal prostheses are currently being developed. On one type, a tiny computer chip is embedded in the eye. The chip has a grid of about 2,500 light-sensing elements called pixels.
Light entering the eye strikes the pixels, which convert the light into electrical signals. The pixels then send the electrical signals to nerve cells behind the retina. Those cells send signals via the optic nerve to the brain for interpretation.
Many people who have had a retinal prosthesis implanted say they can see shapes, colors, and movements that they couldn’t see before. "It was great," said Harold Churchey, who received his retinal prosthesis 15 years after he became totally blind. "To see light after so long—it was just wonderful. It was just like switching a light on."
(572 words. Current Science. April 7, 2000)
Why does macular degeneration cause blindness and other vision problems?
选项
A、Macular degeneration causes improper interpretation by the brain.
B、Macular degeneration makes the retina less sensitive to the light.
C、Macular degeneration changes the functions of rods and cones.
D、Macular degeneration is the result of inadequate supply of blood in the retina.
答案
D
解析
答案的依据在第七段的最后两句:The condition is caused by a lack of adequate blood supply to the central part of the retina. Without blood, the rods, cones, and other cells in the retina die.
转载请注明原文地址:https://kaotiyun.com/show/cL6O777K
0
考博英语
相关试题推荐
ReadtheinformationaboutThomasEdison.Choosethecorrectwordtofilleachgap,fromA,BorC.Foreachquestion29-
Theseminarisfrom4.30to6.00,withtimeallowedforquestionsfromtheaudience.Refreshmentsareservedat6.00.
HowtosetpricesThemethodsadoptedinpricesettingarecrucialtoanybusiness.Whensettingprices,remembercostswill
Ifsustainablecompetitiveadvantagedependsonworkforceskills,Americanfirmshaveaproblem.Humanmanagementisnottradit
1.他是个极其自负的怪人。除非事情与自己有关,否则他从来不屑对世界或世人瞧上一眼。对他来说,他不仅是世界上最重要的人物,而且在他眼里,他是唯一活在世界上的人。他认为自己是世界上最伟大戏剧家之一、最伟大的思想家之一、最伟大的作曲家之一。听听他的谈话,仿佛他就
Anumberofdoctorsinthiscountry(was)askedtofromaneworganization(taking)responsibilityfor(overseeing)thetraining
Alltypesofstressstudy,whetherunderlaboratoryorreal-lifesituations,studymechanismsforincreasingthearousallevelo
Hurricanesareviolentstormsthatcausemillionsofdollarsinpropertydamageandtakemanylives.Theycanbeextremelydange
Hequickly______behindthebuildingtoavoidbeinghurtbythestonesthrowninhisdirection.
Thecarpollutes,butadvancesinfuelqualityandefficiency,andinmicropro-cessedenginetechnology,haveradicallycut_____
随机试题
脓胸纤维板剥除术的适应证是
成人社区获得性肺炎中,主要病原体是()
A.药士的职责B.药师的职责C.从业药师的职责D.驻店药师的职责E.临床药师的职责开展治疗药物监测,进行药动学计算,设计个体化给药方案的是
定性和定量相结合的方法有()。
下列荷载属于可变作用荷载的有()。
会计人员工作交接中,在移交点收时如果有价证券面额与发行价不一致时,按照()交接。
位于市区的某集团总部为增值税一般纳税人,拥有外贸进m口资格。2021年6月经营业务如下:(1)内销一批服装,向客户开具的增值税发票的金额栏中分别注明了价款300万元、折扣额30万元。(2)取得统借统还利息收入50万元、保本理财产品利息收入10.6万元。
为班级授课制奠定理论基础的是()
设f(x)=,求f(x)的间断点并判断其类型.
=__________。
最新回复
(
0
)