La miopía afecta a la vista.

Yes. Both miopía and vista are feminine singular nouns, so they take la.

• la miopía = myopia / nearsightedness
• la vista = sight / eyesight

In Spanish, nouns have grammatical gender, so the article has to match the noun:

• el for masculine singular
• la for feminine singular

Here, both are feminine, so la is correct in both cases.

Afecta is the third-person singular present tense of afectar, which means to affect.

So:

• afectar = to affect
• afecta = affects

In La miopía afecta a la vista, the subject is la miopía, so the verb must be third-person singular:

• La miopía afecta... = Myopia affects...

This a is part of how the verb afectar is often used when talking about what is affected.

So:

• afectar a algo/alguien = to affect something/someone

Examples:

• La contaminación afecta al medio ambiente.
• El ruido afecta a los vecinos.
• La miopía afecta a la vista.

This is not exactly the same as the personal a, although it looks the same. With afectar, the preposition a is commonly used before the thing or person affected.

You may sometimes see or hear afectar used without a, especially in some varieties of Spanish, but in standard Spanish, and especially in careful or neutral usage, afectar a la vista is very natural and widely accepted.

For a learner of Spanish from Spain, La miopía afecta a la vista is the safest and most natural version to use.

Spanish often uses the definite article more than English does.

In English, we might say:

• Myopia affects eyesight

But in Spanish, it is very natural to say:

• La miopía afecta a la vista

Here, la vista means sight/eyesight in a general sense. Spanish often uses el/la/los/las with body parts, abstract ideas, and general categories where English might use no article at all.

They are related, but not always identical.

• la vista often means sight, eyesight, or even view
• la visión usually means vision in a slightly more technical, formal, or abstract sense

In this sentence, la vista sounds very natural for eyesight:

• La miopía afecta a la vista.

You could hear la visión in medical or formal contexts too, but la vista is common and idiomatic.

It is pronounced roughly like:

mee-oh-PEE-ah

The stress falls on -pí- because of the written accent:

• mi-o-pí-a

That accent mark is important because it shows where the stress goes.

The written accent in miopía shows that the stress falls on the í:

• miopía

Without going too deep into accent rules, the accent helps show that the vowel sequence is pronounced in a way that gives stress to -pí- rather than following a more regular stress pattern.

So for learners, the key point is:

• miopía → stress on pí

The subject is La miopía.

That is the thing doing the action of the verb:

• La miopía = subject
• afecta = verb
• a la vista = what is affected

So literally, the structure is:

[La miopía] [afecta] [a la vista].

Yes, Spanish word order is flexible, but the normal, neutral order here is:

La miopía afecta a la vista.

You could change the order for emphasis, but it would sound less neutral. For example:

• A la vista la afecta la miopía.

This is grammatically possible, but much less natural as a basic sentence for a learner. The original version is the best one to learn first.

Exactly.

• la miopía = myopia / nearsightedness, the condition
• miope = myopic / nearsighted, the adjective or noun for a person

Examples:

• Tiene miopía. = He/She has myopia.
• Es miope. = He/She is nearsighted.

So in your sentence, miopía is the medical condition that affects sight.

Yes. La miopía afecta a la vista is fully natural and correct in Spain.

It sounds neutral and clear, and it could appear in everyday explanation, health information, or educational material.