Najpierw optyk zbada źrenice, potem wybierze okulary.

Because these are perfective verbs in Polish. Perfective verbs usually do not have a true present-tense meaning. Their “present-looking” forms normally refer to the future.

• zbada = will examine
• wybierze = will choose / will select

This is very common in Polish:

• bada = is examining / examines (imperfective, present)

• zbada = will examine (perfective, future)

• wybiera = is choosing / chooses (imperfective, present)
• wybierze = will choose (perfective, future)

So the sentence describes a sequence of completed future actions.

Badać is the imperfective verb, and zbadać is its perfective partner.

Very roughly:

• badać = to examine, to be examining, to examine in general
• zbadać = to examine and finish the examination

The prefix z- often gives a sense of completion here. So:

• Optyk bada źrenice. = The optician is examining / examines the pupils.
• Optyk zbada źrenice. = The optician will examine the pupils (and complete that examination).

In your sentence, zbada fits well because it is the first completed step before the next one happens.

This is the same imperfective/perfective contrast.

• wybierać = to choose, to be choosing, to choose repeatedly
• wybrać = to choose and finish choosing

The form wybierze comes from wybrać and means he/she will choose.

So:

• wybiera okulary = is choosing glasses / chooses glasses
• wybierze okulary = will choose the glasses / will choose glasses

Again, the perfective form is used because the sentence describes a completed next step.

Because Polish often drops subject pronouns when the verb form already makes the subject clear.

In wybierze, the ending tells you it is third person singular: he/she/it will choose.

So after optyk appears in the first clause, the second clause does not need to repeat it:

• Najpierw optyk zbada źrenice, potem wybierze okulary.

This naturally means:

• First the optician will examine the pupils, then he/she will choose the glasses.

If you repeated optyk, it would still be grammatical, but less natural unless you wanted emphasis:

• Najpierw optyk zbada źrenice, potem optyk wybierze okulary.

Because źrenice means pupils. A person normally has two pupils, so in this kind of medical/optical context the plural is natural.

Singular and plural are:

• źrenica = pupil
• źrenice = pupils

The sentence says the optician will examine the person’s pupils, not just one pupil.

It is in the accusative plural, because it is the direct object of zbada.

Base form:

• źrenice = nominative plural

Direct object form:

• zbada źrenice = accusative plural

For this noun, the nominative plural and accusative plural happen to look the same, so you do not see a visible change.

Singular forms are easier to see:

• nominative singular: źrenica
• accusative singular: źrenicę

So if the sentence were singular, it would be:

• zbada źrenicę = will examine the pupil

In normal Polish, okulary is a plural-only noun for glasses / spectacles. This is similar to English words like glasses, pants, or scissors, which are usually plural in form.

So:

• okulary = glasses
• not normally okular to mean one pair of glasses

The word okular does exist, but it usually means something else, such as an eyepiece in technical contexts, not everyday glasses.

So in your sentence:

• wybierze okulary = will choose glasses / will choose the glasses

It is the accusative plural, because it is the direct object of wybierze.

Just like źrenice, the form looks the same as the nominative plural:

• nominative plural: okulary
• accusative plural: okulary

This is normal for many non-masculine-personal plural nouns in Polish.

They mark the order of actions:

• najpierw = first / at first / first of all
• potem = then / afterwards / later

So the sentence clearly gives a sequence:

1. Najpierw optyk zbada źrenice.
2. Potem wybierze okulary.

This is a very common way to describe steps in Polish.

No, Polish word order is fairly flexible, but this version is very natural.

Current order:

• Najpierw optyk zbada źrenice, potem wybierze okulary.

You could also say:

• Optyk najpierw zbada źrenice, potem wybierze okulary.

Both are correct. Putting najpierw first gives a nice step-by-step feel and highlights the sequence right away.

Even though Polish word order is flexible, it is not random. Different orders can shift emphasis, but the original sentence is a neutral and natural choice.

Because Polish can connect clauses simply with a comma, especially when the sequence is already clear from words like najpierw and potem.

So:

• Najpierw optyk zbada źrenice, potem wybierze okulary.

is perfectly natural.

You could also say:

• Najpierw optyk zbada źrenice, a potem wybierze okulary.

Adding a makes the connection a little more explicit, something like and then / and after that. Both versions work.

Usually yes. Optyk most often means optician or someone working in optics/eyewear.

In this sentence, the meaning is practical and natural: the person examines the pupils and then helps choose glasses.

Depending on context, English might sometimes use:

• optician
• eye specialist
• occasionally something more specific

But optician is the most straightforward match here.

A rough English-friendly guide is:

• źre sounds somewhat like zhre, with a soft zh sound
• ni sounds like nee
• ce sounds like tseh

So approximately:

• źrenice ≈ zhreh-NEE-tseh

A few helpful points:

• ź is a soft sound, similar to the s in measure, but palatalized
• rz here is also pronounced like a zh sound
• stress in Polish is usually on the second-to-last syllable, so here the stress is on ni:
  • źre-NI-ce

Literally, it says:

• then he/she will choose the glasses

But in real-life context, that often means the optician will select or help select suitable glasses. Polish, like English, can leave some practical details understood from context.

So the exact nuance depends on the situation:

• the optician personally selects a pair,
• the optician recommends a pair,
• or the optician helps the customer choose.

The grammar itself does not force one very specific interpretation beyond choosing/selecting glasses.

Yes, but the meaning would change.

If you use imperfective present forms:

• Najpierw optyk bada źrenice, potem wybiera okulary.

that can sound like:

• First the optician examines the pupils, then chooses the glasses
• or a general/procedural description

Your original sentence with zbada and wybierze is more clearly about a future event and completed steps:

• First the optician will examine the pupils, then will choose the glasses.

So the choice of aspect is very important here.