Korean Writing Correction: Cataracts and Eye Surgery

Not every diary entry is about your day. Some are research notes — you read about something, and you write down what you learned. Today's entry is exactly that: a short summary of what cataracts are, what causes them, and how they're treated. Research-note entries are great writing practice because they push you into explanatory sentences, and explanatory sentences are where English habits leak into Korean the hardest. The big one here: English medical writing loves the passive voice, and Korean doesn't.

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The Original Entry

백내장

백내장에 대해서 알아봤다.

원인 백내장에 원인의 90% 이상이 노령화다. 렌즈의 역활을 하는 수정체가 뿌옇게 흐려지는 것이 원인이다. 수정체의 노령화는 갑자기 생기는 것이 아니라 사실은 10대 후반으로 부터 시작되어 있다고 한다.

증상 수정체 전체에 혼탁이 있는 경우에는 시계 전체가 뿌옇게 보인다. 그외에도 원인에 따라 여러가지 증상이 있다고 한다.

치료법 — 수술 뿌옇게 흐려진 수정체를 제거하고 그 대신에 인공 주정체를 옮겨 놓는 수술이 많이 되고 있다고 한다. 이 방법은 흐려진 수정체를 초음파로 분할 제거한 후 인공 주정체를 삽입한다. 이 방법은 상처가 작고 안전성이 높은 수술이라고 한다.

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Corrections

Correction 1: 수술이 많이 되고 있다 → 수술을 많이 하고 있다

Written: 인공 수정체를 옮겨 넣는 수술이 많이 되고 있다고 한다 Correct: 인공 수정체를 옮겨 넣는 수술을 많이 하고 있다고 한다

This is the single most common structural transfer error English speakers make in Korean, and it hides inside a completely reasonable-looking sentence.

In English, when you don't want to name who does something, you use the passive: "this surgery is widely performed." There's no natural way to say it actively without inventing a subject ("doctors perform it a lot"), which sounds like you're making a claim about doctors rather than about the surgery. So English reaches for the passive constantly in explanatory writing.

Korean solves the same problem a completely different way: it just drops the subject and keeps the verb active. 수술을 많이 하고 있다 literally reads "[they] are doing this surgery a lot" — but 그들이 is never said, and no reader expects it. The actor stays invisible without the verb changing at all. That's the tool Korean uses where English uses the passive.

So when do you actually use 되다? When the event genuinely has no actor — when something comes about by itself, or the result matters and the cause is irrelevant:

• 예약이 취소됐다. (The reservation got cancelled.) — the writer doesn't know or care who cancelled it
• 불이 꺼졌다. (The light went out.) — it went out, nobody flipped a switch

A surgical procedure never happens by itself. Someone performs it. Writing 수술이 되고 있다 makes it sound like the operation is spontaneously occurring, which is why it reads oddly to a native ear even though every word is correct.

Notice the particle has to move with the verb: when 하다 takes over, 수술 becomes the object, so 수술이 → 수술을.

Try it in your diary:

• 요즘 이 방법을 많이 쓴다. (This method is widely used these days.) — active, no subject
• 그 책은 한국어로도 번역했다. (That book was translated into Korean too.) — someone translated it
• 회의가 갑자기 취소됐다. (The meeting was suddenly cancelled.) — genuine 되다, the cause is beside the point

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Correction 2: 옮겨 놓는 → 옮겨 넣는

Written: 그 대신에 인공 수정체를 옮겨 놓는 수술 Correct: 그 대신에 인공 수정체를 옮겨 넣는 수술

English "put" and "place" cover a huge range of destinations — on a table, into a bag, inside your eye. Korean splits that range across two verbs, and the split is about where the thing ends up.

놓다 means to set something down and leave it resting there — on a surface, in the open. 책상 위에 놓다 ("set it on the desk"), 잔을 놓다 ("put the glass down"). The object stays visible, sitting on top of something.

넣다 means to put something into an enclosed space — a bag, a pocket, a container, a body. 가방에 넣다 ("put it in the bag"), 주머니에 넣다 ("put it in your pocket").

An artificial lens is inserted inside the eye, in the space the clouded lens used to occupy. That's unambiguously into, so 넣다 is the only fit. 옮겨 놓다 would describe carrying the lens over and setting it down somewhere — on a tray, next to the patient — which is not what the surgery does.

The compound is worth noticing on its own: 옮겨 넣다 is "move it over and put it in," two actions welded into one verb. Korean builds a lot of everyday verbs this way, and picking the wrong second half is what breaks them.

Try it in your diary:

• 약을 서랍에 넣었다. (I put the medicine in the drawer.)
• 약을 식탁 위에 놓았다. (I set the medicine on the table.)

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A few more polish points

• 역활 → 역할: "Role." This one is misspelled constantly by native speakers too, because 할 and 활 are nearly indistinguishable in fast speech and 활 shows up in so many common words (생활, 활동, 활발). The correct form is 역할. If you use this word often — and diary writers do, describing what something does — it's worth locking in now.
• 시작되어 있다 → 시작되고 있다: These two auxiliaries look similar and mean opposite things. ~아/어 있다 marks a resulting state that stays put: 문이 열려 있다 ("the door is open" — it was opened, and it remains open). ~고 있다 marks something ongoing, still unfolding. The lens aging from your late teens is a process running continuously across decades, not a finished state you can point at, so 시작되고 있다 is the fit.
• 주정체 → 수정체 (twice): A straightforward typo for 수정체, the crystalline lens of the eye. Worth flagging because the entry spells it correctly three other times — a re-read pass catches this instantly, and inconsistency within one entry is the easiest kind of error to self-correct.
• 백내장에 원인의 → 백내장 원인의: 에 marks location or time ("at, in, on"), but this sentence needs possession: "90% of the causes of cataracts." That would technically be 백내장의 원인의, except stacking 의 twice sounds heavy in Korean, so the first one is simply dropped: 백내장 원인의 90%. Two nouns sitting side by side already read as a possessive relationship.
• 10대 후반으로 부터 → 10대 후반부터: Two fixes in one. 부터 attaches directly to the noun with no space before it. And 으로부터 is for sources and people — 친구로부터 편지를 받았다 ("I got a letter from a friend"). For a starting point in time, plain 부터 is what you want.
• 그외에도 → 그 외에도 / 여러가지 → 여러 가지: Spacing. 그 (that) and 여러 (several) are determiners, and determiners are separate words from the noun they modify. Korean spacing rules are forgiving in casual writing, but these two are frequent enough that fixing them cleans up a lot of entries at once.

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The pattern to remember

When you want to write "X is done / is performed / is used" in Korean, stop and ask one question: does an actual person do this?

• Yes, a person does it, you just don't want to name them → keep the verb active and drop the subject: 수술을 많이 한다, 이 방법을 많이 쓴다
• No, it happens on its own, or the cause is genuinely irrelevant → 되다: 취소됐다, 꺼졌다

English speakers default to the passive because English gives them no other way to hide the actor. Korean hides the actor for free, by saying nothing at all. Once you notice that, a whole category of stiff-sounding sentences fixes itself.

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The Corrected Entry

백내장

백내장에 대해서 알아봤다.

원인 백내장 원인의 90% 이상이 노령화다. 렌즈의 역할을 하는 수정체가 뿌옇게 흐려지는 것이 원인이다. 수정체의 노령화는 갑자기 생기는 것이 아니라 사실은 10대 후반부터 시작되고 있다고 한다.

증상 수정체 전체에 혼탁이 있는 경우에는 시계 전체가 뿌옇게 보인다. 그 외에도 원인에 따라 여러 가지 증상이 있다고 한다.

치료법 — 수술 뿌옇게 흐려진 수정체를 제거하고 그 대신에 인공 수정체를 옮겨 넣는 수술을 많이 하고 있다고 한다. 이 방법은 흐려진 수정체를 초음파로 분할 제거한 후 인공 수정체를 삽입한다. 이 방법은 상처가 작고 안전성이 높은 수술이라고 한다.

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✍️ Writing a research-note entry in Korean? Every time you reach for "is done," check whether a person is doing it — Korean would rather drop the subject than switch the verb.

Paste your Korean diary entry into Korean Diary AI and get instant corrections with clear explanations — free to try.