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
医学
Famed singer Steve Wonder can’ t see his fans dancing at his concerts. He can’ t see the hands of his audience as they applaud w
Famed singer Steve Wonder can’ t see his fans dancing at his concerts. He can’ t see the hands of his audience as they applaud w
admin
2013-11-30
68
问题
Famed singer Steve 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 Humayan, 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.
However the retinal prosthesis and other devices 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 fails 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 prosthesis 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 prosthesis 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. "
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 causes inadequate supply of blood in the retina.
答案
D
解析
文章第七段倒数第二句指出“The condition is caused by…of the retina”,即这种情况是由于视网膜中部缺血导致,选项D正确。
转载请注明原文地址:https://kaotiyun.com/show/MtU3777K
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
A、It’soverrated.B、It’sratherboring.C、It’shardtounderstand.D、It’sextremelyinteresting.D女士表示自己从未看过这样有趣的科幻故事,男士讲女士这
Animmediatesearchover1,000squaremilesofseafailedto______singlepieceofwreckage.
Thisenvironmentcanalsoaffectaperson’smentaland______health,
Whilemanyapplaudtheincreasingindividualismandfreedomofchildrenwithinthefamily,otherslamentthelossoffamilyresp
TheAmericanresearchuniversityisaremarkableinstitution,longasourceofadmirationandwonder.Theidyllic(田园诗的),wooded
FamedsingerSteveWondercan’tseehisfansdancingathisconcerts.Hecan’tseethehandsofhisaudienceastheyapplaudw
A、Inakitchen.B、Inanorchard.C、Inagarden.D、Atapicnic.C从他们谈论西红柿,浇水,采摘等可推知出他们在菜园里。
Inspiteofaproblemwiththefaultyequipment,someveryusefulworkwasaccomplished.
A、Thosedamagedcellscanonlybefoundoutbyspecialequipment.B、Therearemoredamagedcellsthannormalones.C、Thosedamag
随机试题
下图中的哪一个代表了买入看涨期权的盈亏()
Iknewnothingabouthisjourney______hewaslikelytobeawayforthreemonths.
四逆散中柴胡与白芍的用量比例是
两种不同牙膏使用者的患龋率如下表,试推断他们的患龋率有无差别,可选用的最适当方法是
(),构成了风险的随机性
劳动法律关系的产生,是指劳动法律关系主体之间为实现一定的劳动过程,依照劳动法规,通过签订()而建立的劳动权利与劳动义务关系。
果网络的传输速率为56Kbps,要传输5M字节的数据大约需要的时间是
内存的大部分由RAM组成,RAM中存储的数据在断电后将______丢失。
Itisimportantthatyoureplytoourletterwithout______.
Doctorsbaffledbyanunexplainedrashonpeople’searsorcheeksshouldbeonalertforaskinallergycausedtoomuch【M1】_____
最新回复
(
0
)