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原田英語の時事英語ジュニア｜英語ニュース ワークシート（高校生レベル）

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スマホの時間と近視の関係　画面を見る時間が1時間増えるとリスク21%アップ

Each Extra Hour of Screen Time Raises Myopia Odds, Review Finds

音声・ゲームはこちらから

1Every additional hour of daily screen time is linked to 21 percent higher odds of myopia, or nearsightedness, a review published on February 21, 2025, found. The review appeared in the journal JAMA Network Open. Researchers in South Korea and Ireland combined data from 45 studies involving more than 335,000 people. The participants in the main analysis were mostly children, with an average age of about nine.

2Myopia makes distant objects look blurry, while nearby objects stay clear. Scientists have long linked myopia to spending many hours on close-up work. The researchers counted smartphones, tablets, game consoles, computers and televisions as screen time.

3A second analysis of 34 studies showed how the risk changed with the amount of use. Below one hour a day, the link was not statistically significant. The risk then rose steeply between one and four hours a day. At four hours, the odds of myopia were about twice as high as with no screen time, and the increase slowed after that.

4The authors described one hour a day as a possible safety threshold. However, they warned against relying on that number, since reading and other close-up activities may also raise the risk. Most of the studies were cross-sectional, which means they measured screen time and eyesight at a single point in time. As a result, the review cannot prove that screens cause myopia, and the certainty of the evidence was rated low.

5The authors said their results could help guide future research, education and health policies on myopia.

Words　単語

additionalA2形追加のadded to what you already have
oddsB2名見こみ、確率how likely it is that something will happen
myopia外名近視an eye problem that makes far things look unclear
participantsB1名参加者（participant の複数形）people who take part in something
distantB1形遠くのa long way away from you
statistically significantA2形統計的に意味のある（偶然とは言えない）clear in the numbers, not just by chance
steeplyB1副急に、急角度でgoing up or down very fast
threshold外名境目、限界の値the point where something starts to change
relying onB1熟～にたよることtrusting and needing something
certaintyB1名確かさ、確実性how sure you can be about something

単語のレベル：CEFR-J（『CEFR-J Wordlist Version 1.6』 東京外国語大学投野由紀夫研究室. （URL: https://www.cefr-j.org/download.html より 2026年8月ダウンロード））

1. Reading Quiz　本文の内容に合うものを選ぼう

  1. Where was the review published?

    A. In a game magazineB. In a school newsletterC. In the journal JAMA Network OpenD. On a video site

  2. About how old were the participants in the main analysis on average?

    A. About nineB. About 15C. About 21D. About 45

  3. What happened to the risk between one and four hours a day?

    A. It stayed the same.B. It went down.C. It disappeared.D. It rose steeply.

  4. Why did the authors warn against relying on the one-hour number?

    A. Because screens are always safeB. Because reading and other close-up activities may also raise the riskC. Because children do not use screensD. Because the study was about adults only

  5. How was the certainty of the evidence rated?

    A. Very highB. HighC. PerfectD. Low

2. True or False　正しければ T、違っていれば F

  1. (     ) The researchers combined data from 45 studies.

  2. (     ) Televisions were not counted as screen time.

  3. (     ) At four hours a day, the odds were about twice as high as with no screen time.

  4. (     ) Most of the studies followed the same children for many years.

3. Fill in the Blanks　下の語から選んで空らんをうめよう（形を変えずに）

oddsparticipantsadditionalMyopiathresholdsteeply

  1. The authors described one hour a day as a possible safety _____.

  2. Every _____ hour of daily screen time is linked to 21 percent higher odds of myopia, or nearsightedness, a review published on February 21, 2025, found.

  3. The risk then rose _____ between one and four hours a day.

  4. _____ makes distant objects look blurry, while nearby objects stay clear.

  5. The _____ in the main analysis were mostly children, with an average age of about nine.

  6. At four hours, the _____ of myopia were about twice as high as with no screen time, and the increase slowed after that.

4. Word Order　語を並べかえて正しい文にしよう

  1. ( journal / the / Network / The / JAMA / appeared / Open / review / in ) .

  2. ( while / look / objects / nearby / stay / distant / Myopia / makes / clear / objects / blurry, ) .

  3. ( and / risk / four / one / then / The / hours / between / a / rose / day / steeply ) .

5. Think and Write　英語で答えてみよう

  1. Should schools limit how long students use tablets in class? Give your reasons.（学校は授業でタブレットを使う時間を制限すべきだと思いますか？理由も答えよう。）

  2. Why is it important to know whether a study shows a link or a cause?（研究が示しているのが「関係」なのか「原因」なのかを知ることが大切なのはなぜでしょうか？）

Answers　解答

1. (1) C　(2) A　(3) D　(4) B　(5) D

2. (1) T　(2) F　(3) T　(4) F

3. (1) threshold　(2) additional　(3) steeply　(4) Myopia　(5) participants　(6) odds

4.

  1. The review appeared in the journal JAMA Network Open.
  2. Myopia makes distant objects look blurry, while nearby objects stay clear.
  3. The risk then rose steeply between one and four hours a day.

全文訳

12025年2月21日に発表された研究のまとめ（レビュー）で、1日の画面時間が1時間増えるごとに、近視になる見こみが21%高くなることがわかりました。このレビューは学術誌「JAMAネットワーク・オープン」に掲載されました。韓国とアイルランドの研究者たちが、33万5000人以上が参加した45の研究のデータをまとめました。主な分析の参加者はほとんどが子どもで、平均年齢は約9歳でした。

2近視になると、近くのものははっきり見えたままなのに、遠くのものがぼやけて見えます。科学者たちは以前から、近視と、近くを見る作業を長時間することとの関係を指摘してきました。研究者たちは、スマートフォン、タブレット、ゲーム機、パソコン、テレビを画面時間として数えました。

334の研究を使った2つ目の分析では、使う時間によってリスクがどう変わるかが示されました。1日1時間未満では、統計的にはっきりした関係は見られませんでした。そこから、1日1〜4時間のあいだでリスクは急に上がりました。4時間では、近視になる見こみは画面時間ゼロのときのおよそ2倍になり、その後は上がり方がゆるやかになりました。

4著者たちは、1日1時間が「安全の目安」になるかもしれないと述べました。ただし、読書など近くを見るほかの活動もリスクを高めるかもしれないとして、その数字にたよりすぎないよう注意しました。研究の多くは「横断研究」で、画面時間と視力を1つの時点でだけ測ったものでした。そのためこのレビューでは、画面が近視の原因だと証明することはできず、証拠の確かさも「低い」と評価されました。

5著者たちは、この結果が近視についての今後の研究や教育、健康政策に役立つ可能性があると述べました。

文法ポイント：倍数表現（twice as ～ as ...）

twice as high as ～ で「～の2倍高い」。本文の the odds of myopia were about twice as high as with no screen time がその例。three times as ～ as ... なら「3倍」。

出典：Optometry Today (AOP)、HealthDay、Ophthalmology Management ほか（記事は原田英語の時事英語ジュニアのオリジナル）｜https://www.haradaeigo.com/jijieigo-junior/news/2025-02-21-screen-time-nearsightedness/