21/11/2025
🥕 “Carrots, Eyes & the Myth of Superhuman Vision”
Weekend fun fact- Dr Chua 22/11/2025
We’ve all grown up hearing, “Eat more carrots, they’re good for your eyes!”
But how much of that is true… and how much is clever wartime storytelling? Let’s take a closer look — with proper ophthalmology, science, and a dash of history.
👁️ 1. Yes, carrots ARE good for the eyes — but don’t expect miracles
Carrots are packed with beta-carotene, which your body converts into vitamin A. This helps with:
• Keeping your cornea healthy and tear production
• Supporting your retina
• Forming rhodopsin, the pigment that lets you see in dim light
A severe vitamin A deficiency can lead to night blindness and dry eyes — conditions eye doctors still see in areas with poor nutrition.
But here’s the key point:
🟠 Your body only converts beta-carotene when needed, so you cannot overdose from eating carrots.
⚠️ 2. Carrots cannot cause vitamin A poisoning… but fish liver oil can
Vitamin A from animal sources, especially fish liver oil, comes as preformed vitamin A — and too much of it is toxic.
Excess can cause:
• Headache
• Liver injury
• Peeling skin
• Raised brain pressure (in severe cases)
Carrots, on the other hand, contain beta-carotene which your body regulates safely. So no — snacking on carrots will not poison you.
🟡 3. Carotenemia: When too many carrots turn your skin yellow
Eat a lot of carrots and your skin (especially palms and soles) may turn a yellow-orange colour. This harmless condition is called carotenemia.
It’s completely reversible — stop overloading on carrot juice and the colour fades within weeks.
💡 Important ophthalmologist note:
👉 Carotene does NOT stain the sclera or conjunctiva. So the white of the eye remains white. This is how we distinguish carotenemia from jaundice, where bilirubin does turn the sclera yellow.
This single point often reassures worried patients instantly.
🎯 4. No, carrots do NOT give you superhuman night vision
This is where British history becomes deliciously clever. During World War II, RAF pilots mysteriously became excellent at shooting down enemy planes at night.
The government explained it by saying:
“Our pilots eat lots of carrots — that’s why their night vision is superb.”
It made great headlines… but it wasn’t true.
📡 The real secret was newly developed airborne radar technology.
The carrot story was a smokescreen to protect military intelligence — and Germany believed it!
Thus, the myth of carrot-powered night vision was born.
👁️ 5. What do ophthalmologists really think?
Carrots contribute to healthy eyes, but they:
• ❌ Don’t give razor-sharp vision
• ❌ Don’t cure myopia
• ❌ Don’t reverse eye disease
• ❌ Don’t turn you into an RAF night-fighter ace
They do help you maintain enough vitamin A.
But proper eye care is far more than just diet , a regular eye check ensure your eyes are in good shape.
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🥕 《红萝卜、眼睛与“超人夜视力”的迷思》
周末眼睛小常识-蔡鐘能眼科医生21/11/2025
从小我们常听到一句话：
“要眼睛好，就要多吃红萝卜！”
到底这句话有多少科学依据？又有多少是历史故事？今天，就让我们用眼科角度、科学知识，再加上一点英国战争史，来看看真相。
👁️ 1. 红萝卜确实对眼睛有好处——但别期待奇迹
红萝卜富含 β-胡萝卜素（beta-carotene），人体会把它转换成维生素 A，用来：
• 维持角膜健康
• 支持视网膜功能
• 形成 视紫质（rhodopsin） —— 让我们在昏暗中看得到东西
严重缺乏维生素 A 会导致夜盲症、眼睛干燥，甚至永久性损害。
这些情况在缺乏营养的地区至今仍然存在。
但重点是：
🟠 身体只会在需要时，才把 β-胡萝卜素转换成维生素 A。所以你吃再多红萝卜，也不会“维 A 中毒”。
⚠️ 2. 红萝卜不会造成维生素 A 中毒……但鱼肝油会
动物来源的维生素 A（尤其是鱼肝油）属于 预形成维生素 A（preformed Vitamin A），摄取过多会有毒性。
过量会导致：
• 头痛
• 肝脏受损
• 皮肤脱皮
• 严重者甚至颅内压升高
红萝卜里的 β-胡萝卜素却不会，因为身体会自动调节转换量。所以放心——吃红萝卜不会中毒。
🟡 3. 胡萝卜素血症：吃太多红萝卜皮肤会变黄
如果你每天把红萝卜当水喝，皮肤（特别是手掌、脚掌、鼻唇沟）可能出现黄橙色。
这种无害的情况叫 胡萝卜素血症（carotenemia）。停止过量吃红萝卜后，几周内就会恢复正常。
💡 眼科医生最重要的提醒：
👉 胡萝卜素不会把结膜或巩膜染黄。
也就是说：
眼白依然是白色的。
这也是我们分辨它和 黄疸（jaundice） 的关键之一，因为黄疸会把眼白染成黄色。很多病人听到这里就放心了。
🎯 4. 红萝卜能让你变成“夜视超人”吗？
这里就有趣了。第二次世界大战期间，英国皇家空军（RAF）夜间击落德军飞机的成绩突然大幅提升。英国官方解释说：
“我们的飞行员吃很多红萝卜，所以夜视力特别好。”
听起来很英雄——但其实是 战争宣传。
真正的秘密是：
📡 英国刚刚研发出机载雷达系统。
为了保密，就用“红萝卜提升夜视力”来掩盖科技突破。
德国人真的相信了，还鼓励人民多吃红萝卜！这就是“红萝卜夜视力”的经典神话。
👁️ 5. 医生真正的看法
红萝卜对眼睛有益，但它：
• ❌ 不会让视力变 20/20
• ❌ 不会治好近视
• ❌ 不会逆转眼疾
• ❌ 不会让你变成 RAF 夜战王牌
@
它能做的，就是协助维持足够的维生素 A。
但真正的眼睛保健远不止吃菜。想要真的保护好眼睛, 定期眼睛检查是明智的选择。
#蔡鐘能眼科医生 #马来西亚眼科医生 #国际眼科中心 #古晋眼科中心 #诗巫眼科中心 #红萝卜 #🥕
