Ostrość wzroku jest dobra, ale tekst jest rozmazany.

Ostrość means sharpness or acuity, but by itself it can refer to sharpness in a general sense.
Wzroku means of eyesight / of vision, so ostrość wzroku specifically means visual acuity or sharpness of vision.

This is a very common Polish pattern:

• ostrość noża = the sharpness of a knife
• kolor oczu = the color of the eyes
• problem zdrowia = a health problem

So wzroku narrows down what kind of sharpness is being discussed.

Because it is in the genitive case.

In ostrość wzroku, the second noun tells us whose or what kind of sharpness it is: sharpness of vision. In Polish, this of relationship is often expressed with the genitive.

The base form is:

• wzrok = eyesight, vision

The genitive singular is:

• wzroku = of eyesight / of vision

So:

• ostrość wzroku = sharpness of vision

Because dobra agrees with ostrość, and ostrość is a feminine noun.

In Polish, adjectives must agree with the noun in gender, number, and case.

Here:

• ostrość = feminine singular
• dobra = feminine singular form of dobry (good)

So:

• Ostrość wzroku jest dobra. = The visual acuity is good.

If the noun were masculine, you would use dobry:

• Wzrok jest dobry. = The eyesight is good.

Because rozmazany describes tekst, and tekst is a masculine noun.

Again, adjectives agree with the noun they describe:

• tekst = masculine singular
• rozmazany = masculine singular form of blurred / smudged

Compare:

• tekst jest rozmazany = the text is blurred
• książka jest rozmazana = the book is blurred/smudged-looking (książka is feminine)
• zdjęcie jest rozmazane = the photo is blurred (zdjęcie is neuter)

Here rozmazany means blurred, smudged, or out of focus-looking.

It comes from the verb rozmazać, which literally has the sense of to smear or to smudge. Because of that, rozmazany can be used in a few related ways:

• for text or images that look blurry
• for makeup that has smeared
• for something physically smudged

In this sentence, for tekst, the natural English meaning is blurred.

In this sentence, repeating jest is the normal and clear way to say it:

• Ostrość wzroku jest dobra, ale tekst jest rozmazany.

Each clause has its own predicate:

• ostrość wzroku jest dobra
• tekst jest rozmazany

In informal speech, Polish sometimes omits forms of to be, especially in the present tense, but with this kind of standard descriptive sentence, keeping jest is the most natural and correct choice for learners.

So this version is the safest and most standard.

Yes. Polish has no articles, so there is no direct equivalent of the or a/an.

That means tekst can mean:

• the text
• a text
• just text, depending on context

In this sentence, English would usually translate it as the text is blurred, because it sounds like the speaker is referring to some specific text they are trying to read. But the Polish sentence itself does not mark definiteness the way English does.

Context tells you which meaning is intended.

The basic order here is very natural and neutral:

• Ostrość wzroku — subject
• jest dobra — predicate
• ale — but
• tekst — subject
• jest rozmazany — predicate

So the pattern is roughly:

Subject + jest + adjective, ale + subject + jest + adjective

Polish word order is more flexible than English, so changes are possible for emphasis. For example:

• Tekst jest rozmazany, ale ostrość wzroku jest dobra.

This changes the focus, but not the basic meaning.

For learners, the original order is the most neutral and easiest to use.

Yes, ale is the normal Polish word for but in this kind of contrast.

It connects two contrasting statements:

• visual acuity is good
• but the text is blurred

That contrast is important: the problem is not the person’s eyesight, but the text itself.

In everyday use, ale is very common and usually matches English but quite closely.

Not exactly.

• wzrok = eyesight, vision, sense of sight
• oczy = eyes

So:

• ostrość wzroku = sharpness of vision / visual acuity
• ostrość oczu would sound strange in this context

If you are talking about how well someone sees, Polish usually uses wzrok, not oczy.

Compare:

• Mam dobry wzrok. = I have good eyesight.
• Mam niebieskie oczy. = I have blue eyes.

A rough guide for an English speaker:

• ostrość ≈ OS-troshch
• wzroku ≈ VZRO-koo

A few useful pronunciation notes:

• w in Polish sounds like English v
• rz usually sounds like the zh sound in measure
• ó sounds like oo
• ść is a soft cluster, something like shch said very softly

So the whole phrase is roughly:

• OS-troshch VZRO-koo

Polish pronunciation is more regular than English spelling, but clusters like wzr- and endings like -ść can take practice.

It sounds a bit formal or clinical.

A more everyday sentence might be:

• Mam dobry wzrok. = I have good eyesight.

But ostrość wzroku is very natural in:

• medical settings
• optometry or ophthalmology
• discussions of vision testing
• more precise descriptions

So the sentence is correct and natural, but it sounds more technical than casual everyday speech.

Sometimes, but not always.

• tekst = text, writing, written content in general
• napis = inscription, caption, sign, wording displayed somewhere

If you mean written content on a screen, page, or document, tekst is usually the better general word.

If you mean a label, subtitle, or sign, napis may be more appropriate.

So in this sentence, tekst jest rozmazany is the broad and natural choice.

They are both in the nominative case, because they are the subjects of their clauses.

• Ostrość wzroku jest dobra.
  • ostrość = nominative subject
• tekst jest rozmazany.
  • tekst = nominative subject

Meanwhile, wzroku is genitive because it depends on ostrość and means of vision.

So the case pattern is:

• ostrość — nominative
• wzroku — genitive
• tekst — nominative

Yes, that is exactly the contrast the Polish sentence suggests.

The structure separates two ideas:

• Ostrość wzroku jest dobra = the person’s eyesight/visual acuity is fine
• ale tekst jest rozmazany = but the text itself appears blurred or is blurred

So the sentence implies that the issue is not the viewer’s vision, but the text. That is why the contrast with ale is important.