Całkiem dobrze widzę w tych okularach.

Because dobrze is an adverb, and it describes how you see. The verb widzę means I see, so you need an adverb: I see well.

• dobry = good, as an adjective for nouns
• dobrze = well, as an adverb for verbs

So:

• dobry okulista = a good eye doctor
• dobrze widzę = I see well

Here całkiem means something like quite, fairly, or pretty.

So całkiem dobrze means:

• quite well
• fairly well
• pretty well

It is usually less strong than bardzo dobrze.

Compare:

• Widzę dobrze. = I see well.
• Widzę całkiem dobrze. = I see quite well.
• Widzę bardzo dobrze. = I see very well.

A useful warning: całkiem can sometimes mean completely in other contexts, but in this sentence it means quite/fairly.

Polish often leaves out subject pronouns when they are clear from the verb ending.

• widzę already means I see

So ja is not necessary.

You could say:

• Ja całkiem dobrze widzę w tych okularach.

But adding ja usually gives extra emphasis, as in I see quite well in these glasses.

Widzę is the 1st person singular present tense of widzieć.

So:

• widzę = I see
• widzisz = you see
• widzi = he/she/it sees

In this sentence, widzę matches the understood subject I.

Because after w meaning in or while wearing, Polish uses the locative case when there is no movement.

The basic form is:

• te okulary = these glasses

But after w, it changes to:

• w tych okularach = in these glasses / wearing these glasses

So both words change form:

• te → tych
• okulary → okularach

In Polish, okulary is normally a plural-only noun when it means glasses/eyeglasses. This is similar to English, where we also usually say glasses rather than a glass for eyewear.

So you say:

• te okulary = these glasses
• mam nowe okulary = I have new glasses
• w tych okularach = in these glasses

Polish does have the singular okular, but that usually means something like a single lens, eyepiece, or one part of the glasses, not the whole pair in everyday use.

Yes, w literally often means in, but in Polish it is also commonly used with clothing and things worn on the body.

So:

• w okularach = in glasses / wearing glasses
• w butach = in shoes
• w płaszczu = in a coat

In natural English, we would usually say wearing these glasses or with these glasses on, but Polish often uses w for this idea.

Yes, but it means something slightly different.

• w tych okularach focuses on the fact that you are wearing the glasses
• przez te okulary focuses more on looking through the glasses

In everyday speech, if you mean while wearing these glasses, I can see quite well, then w tych okularach is the most natural choice.

Przez te okulary is possible, but it sounds more like attention is on the lenses themselves or the optical effect.

Yes, Polish word order is fairly flexible.

This sentence could also be:

• W tych okularach całkiem dobrze widzę.
• Widzę całkiem dobrze w tych okularach.
• Całkiem dobrze w tych okularach widzę.

The basic meaning stays the same, but the emphasis changes.

The given order sounds natural and neutral. It puts the adverb phrase całkiem dobrze early, so the speaker highlights how well they can see.

No. Całkiem dobrze is weaker.

• całkiem dobrze = quite well / fairly well
• bardzo dobrze = very well

So if you say:

• Całkiem dobrze widzę w tych okularach

it suggests the glasses help a lot, but maybe not perfectly.

If you said:

• Bardzo dobrze widzę w tych okularach

that would sound stronger and more confident.

Here tych is the locative plural form of the demonstrative te in this phrase.

You can think of it like this:

• te okulary = these glasses
• w tych okularach = in these glasses

For this noun, after w, Polish needs the locative plural, so the phrase changes form.

This is a very common pattern to learn as a whole:

• te okulary
• w tych okularach

Usually, yes. The most natural interpretation is that the speaker is talking about seeing well while wearing those glasses.

So the sentence normally suggests a present, practical situation:

• I have these glasses on
• and with them, I can see quite well

Depending on context, it could also be a more general statement about that pair of glasses, but the usual reading is immediate and concrete.