Мне нужен глазной врач, потому что у меня болит глаз.

Russian often expresses I need X with the pattern:

мне нужен / нужна / нужно / нужны + noun

Literally, it is something like to me, X is needed.

So:

• мне = to me (dative case)
• нужен = needed
• глазной врач = eye doctor

This is a very common and natural way to say that you need something or someone.

You can also use verbs like нуждаться, but that is usually more formal and often means to be in need of rather than the everyday I need.

So Мне нужен глазной врач is the normal everyday Russian way to say it.

Нужен is the short form of the adjective нужный (needed, necessary).

In this construction, it agrees with the thing that is needed:

• нужен = masculine singular
• нужна = feminine singular
• нужно = neuter singular
• нужны = plural

Here, the needed thing is врач, which is grammatically masculine singular, so we use нужен:

• Мне нужен врач. = I need a doctor.

Examples:

• Мне нужна помощь. = I need help.
• Мне нужно лекарство. = I need medicine.
• Мне нужны очки. = I need glasses.

Because in this structure, Russian treats the person who needs something as the experiencer or recipient of the need, not as the grammatical subject in the same way English does.

So:

• мне = to me / for me
• тебе = to you
• ему = to him
• нам = to us

Compare:

• Мне нужен врач. = I need a doctor.
• Тебе нужен врач? = Do you need a doctor?
• Нам нужен врач. = We need a doctor.

This is just the normal case pattern used with нужен.

Yes. Глазной is an adjective built from глаз (eye), so глазной врач literally means eye doctor.

This is understandable and natural, though in modern Russian people also very often say:

• окулист
• офтальмолог

Both mean an eye specialist, though офтальмолог is the more technical/medical term.

So these are all possible depending on context:

• глазной врач
• окулист
• офтальмолог

For a learner, глазной врач is very transparent because you can clearly see the connection to глаз.

Russian very often uses у + genitive to express possession in statements about physical condition, age, existence, and similar ideas.

So:

• у меня = with me / in my possession, which in natural English becomes I have / my

In sentences about pain, Russian commonly says:

• У меня болит голова. = I have a headache. / My head hurts.
• У меня болит зуб. = My tooth hurts.
• У меня болит глаз. = My eye hurts.

You can say Мой глаз болит, and it is understandable, but У меня болит глаз sounds more natural in ordinary speech.

Because the verb agrees with the thing that hurts.

Here:

• глаз = singular
• so the verb is болит = singular

If both eyes hurt, then:

• глаза = plural
• so the verb becomes болят

Compare:

• У меня болит глаз. = One eye hurts.
• У меня болят глаза. = My eyes hurt.

So the singular in your sentence suggests that one eye is hurting.

These words are related, but they are used differently.

болит comes from болеть in the sense to hurt / to ache:

• У меня болит глаз. = My eye hurts.
• У меня болит спина. = My back hurts.

болеет can mean is ill / is sick, often about a person, not usually a body part in this exact sense:

• Он болеет. = He is sick.

больно means it hurts / painful, and it is often used differently:

• Мне больно. = It hurts.
• Мне больно смотреть. = It hurts to look.

So for a body part hurts, Russian typically uses:

У меня болит + body part

In some contexts, Russian can omit information that is obvious, but here у меня is very natural and usually expected.

Without it, болит глаз just means an eye hurts / the eye hurts, but it does not clearly say whose eye.

So:

• У меня болит глаз. = My eye hurts.
• У него болит глаз. = His eye hurts.
• У неё болит глаз. = Her eye hurts.

Including у меня makes the sentence complete and clear.

Yes, Russian word order is fairly flexible, though different orders can sound more neutral, more emphatic, or more conversational.

Your sentence has a very natural order:

Мне нужен глазной врач, потому что у меня болит глаз.

Possible variations include:

• Потому что у меня болит глаз, мне нужен глазной врач.
• Глазной врач мне нужен, потому что у меня болит глаз.

These are all understandable, but the original version is a good neutral choice.

In Russian, word order often helps show emphasis rather than basic grammar.

Because потому что means because and introduces a subordinate clause.

So the sentence has two parts:

1. Мне нужен глазной врач
2. потому что у меня болит глаз

Russian normally puts a comma before потому что in this kind of sentence:

• Я остался дома, потому что был болен.
• Мне нужен глазной врач, потому что у меня болит глаз.

So the comma here is standard punctuation.

Врач is grammatically masculine, even when it refers to a female doctor.

So you would still commonly say:

• Мне нужен врач.

If you are talking about a specific female doctor, Russian may sometimes use feminine agreement in informal speech, but with profession nouns like врач, masculine forms are still very common and standard.

In your sentence, нужен agrees with the noun врач, which is grammatically masculine, not with the real-life gender of the doctor.