A visão melhorou.

Here, a means the.

In Portuguese:

• a = feminine singular the
• uma = feminine singular a/an

So a visão means the vision / the eyesight, not a vision in the indefinite sense.

Because visão is a feminine noun in Portuguese.

Portuguese nouns have grammatical gender, and the article has to match:

• a visão
• a televisão
• a decisão

There is no special logic you can always rely on here; you usually learn the noun together with its article. So it is best to memorize it as a visão, not just visão.

Melhorou is the third-person singular preterite of melhorar.

So:

• infinitive: melhorar = to improve / to get better
• melhorou = improved / got better

In this sentence, it describes a change that happened in the past and is seen as completed.

Because in Portuguese, the third-person singular is used not only for he and she, but also for it and for any singular noun.

The subject here is a visão, which is singular, so the verb is singular too:

• A visão melhorou.

If the subject were plural, the verb would also be plural:

• Os sintomas melhoraram.

So this is just normal subject-verb agreement.

Here, it is being used intransitively.

That means the subject itself is what improved:

• A visão melhorou. = the vision improved

But melhorar can also be transitive, where something improves something else:

• O tratamento melhorou a visão.

So both are possible:

• A visão melhorou. = the eyesight got better
• Algo melhorou a visão. = something improved the eyesight

They are close, but not identical.

• A visão melhorou focuses on the change: the vision improved
• A visão está melhor focuses on the current state: the vision is better

So:

• melhorou = got better / improved
• está melhor = is better now

Both are natural, but they highlight different things.

A rough Brazilian Portuguese pronunciation is:

• visão ≈ vee-ZOWN, with a nasal ending

A few helpful points:

• the s between vowels sounds like z
• ão is a very common Brazilian Portuguese ending and is nasal
• the stress falls on the last syllable: vi-ZÃO

It is better to think of ão as a sound you imitate, rather than trying to spell it exactly with English sounds.

The mark over ã is a tilde.

It shows that the vowel is nasalized. So visão is not pronounced like a plain a sound. The ending -ão has a nasal sound that is extremely common in Portuguese.

So visão is not:

• vi-sao

It is:

• vi-são, with a nasal ão

This is an important spelling and pronunciation feature in Portuguese.

Not always.

Visão can mean:

• physical vision / eyesight
• figurative vision, such as an outlook or way of seeing things

However, in a sentence like A visão melhorou, the most natural interpretation is usually eyesight improved, especially in a medical or everyday context.

So the exact meaning depends on context, but physical vision is the most likely one here.

Both can relate to seeing, but they are not always used the same way.

Visão often means:

• vision
• eyesight
• the faculty of seeing
• figurative vision

Vista can mean:

• sight
• view
• eyesight, especially in more everyday or colloquial usage

In Brazilian Portuguese, people often say things like:

• Minha vista está ruim.

That is very natural in everyday speech for my eyesight is bad.

So:

• visão can sound a bit more neutral or technical
• vista is also very common, especially in daily conversation

Normally, no. In standard Portuguese, A visão melhorou is the natural full sentence.

Without the article:

• Visão melhorou

it sounds incomplete, unnatural, or like a headline or note.

Portuguese uses articles more often than English does, so learners should get used to saying:

• A visão melhorou
• A dor passou
• O problema acabou

rather than dropping the article.

Yes, absolutely.

• A visão melhorou = natural when the context already makes it clear whose vision you mean
• Sua visão melhorou = more explicit, meaning your vision improved

Portuguese often leaves out possessives when the context is obvious, especially with things connected to the body or personal condition.

So both are possible, but A visão melhorou is perfectly natural if the person is already understood from the situation.