Рецепт на очки уже готов.

Yes, рецепт can mean both:

• recipe (for cooking)
• prescription (from a doctor)

This is normal in Russian. The exact meaning depends on context.

So in:

• Рецепт на очки уже готов.

рецепт means a medical prescription, not a cooking recipe.

This is especially common in contexts like:

• рецепт на очки — a prescription for glasses
• рецепт на лекарства — a prescription for medicine

In Russian, рецепт на + accusative is a common pattern meaning a prescription for ... something.

So:

• рецепт на очки = prescription for glasses
• рецепт на линзы = prescription for contact lenses
• рецепт на лекарство = prescription for medicine

Using для would sound unnatural here, because для usually means for the benefit/use of something, not prescribing something.

So this is mainly a vocabulary/government pattern you just learn with the noun:

• рецепт на что?

Очки is in the accusative case because it follows на in the expression рецепт на что?

The basic dictionary form is:

• очки — glasses

For an inanimate plural noun like очки, the accusative plural looks the same as the nominative plural:

• nominative: очки
• accusative: очки

So the form does not change, but the case is still accusative.

Because готов is the short form of the adjective готовый.

In Russian, short-form adjectives are often used in sentences like X is ready, X is necessary, X is important, etc.

So:

• готовый рецепт = a ready/prepared prescription
• рецепт готов = the prescription is ready

In this sentence, the adjective is being used as the predicate, so the short form is natural:

• Рецепт ... готов.

Also, рецепт is masculine singular, so the short form is:

• masculine: готов
• feminine: готова
• neuter: готово
• plural: готовы

In Russian, the verb to be is usually omitted in the present tense.

So:

• Рецепт на очки уже готов.

literally works like:

• Prescription for glasses already ready.

But naturally in English we translate it as:

• The prescription for glasses is already ready.

This is very normal in Russian:

• Я занят. — I am busy.
• Она дома. — She is at home.
• Документ готов. — The document is ready.

Уже means already.

It shows that the action or state has been completed earlier than expected, or that the result is now available.

So:

• Рецепт на очки уже готов.
• The prescription for glasses is already ready.

It suggests something like:

• it has been completed
• you do not need to wait anymore
• it is available now

Word order with уже is fairly flexible, but here its position is very natural.

Yes. Очки is normally a plural-only noun in Russian, like English glasses.

So you usually say:

• очки — glasses
• новые очки — new glasses
• эти очки — these glasses

There is no normal singular form meaning one pair of glasses in everyday usage.

This is why you see a plural noun after на, even though the whole subject рецепт is singular.

The subject is рецепт.

That is why the adjective is masculine singular:

• рецепт ... готов

The phrase на очки is not the subject; it just describes what kind of prescription it is.

So the structure is:

• Рецепт — subject
• на очки — modifier/complement of рецепт
• уже готов — predicate

Yes. A few close alternatives are possible, for example:

• Рецепт на очки готов. — The prescription for glasses is ready.
• Ваш рецепт на очки уже готов. — Your prescription for glasses is already ready.
• Рецепт уже готов. — The prescription is already ready.

But Рецепт на очки уже готов is perfectly natural.

If you wanted a more formal or medical phrasing, people might also use other nouns in some contexts, but рецепт на очки is common and understandable.