Szkła progresywne pomogą, jeśli wzrok się pogorszy i często mrużysz oczy.

Szkła progresywne means progressive lenses. It refers to the lenses themselves, not necessarily the whole pair of glasses.

• szkła = lenses
• okulary = glasses

So:

• szkła progresywne = progressive lenses
• okulary progresywne = progressive glasses

In everyday speech, people may use both, depending on whether they want to focus on the lenses or the glasses as a whole.

Because the sentence is talking about lenses in general, and glasses normally have two lenses.

Here szkła is the subject of the sentence, so the verb is also plural:

• szkła ... pomogą = the lenses will help

Also, in optical language, szkła often means lenses, even though the singular szkło usually means glass as a material.

It is in the nominative plural, because it is the subject of pomogą.

You can tell from the agreement:

• szkła progresywne — plural
• pomogą — 3rd person plural

So the structure is basically:

• Progressive lenses will help

You are right that Polish adjectives often come before the noun. For example, ładny dom = a nice house.

But in product names, technical terms, and more label-like expressions, the adjective can come after the noun. Szkła progresywne sounds quite natural in an optical or commercial context.

You may also hear:

• progresywne szkła

That is also understandable. The version in the sentence feels a bit more like a standard product term.

Pomogą is the 3rd person plural form of pomóc.

Important point: pomóc is a perfective verb, so its present-looking forms usually have future meaning.

So:

• pomogą = they will help

It agrees with szkła, which is plural.

This is a very common Polish pattern.

After jeśli = if, Polish often uses a perfective verb in a form that looks like the present tense but actually refers to the future.

So:

• jeśli wzrok się pogorszy = if your eyesight gets worse

That is more natural here than:

• jeśli wzrok będzie się pogarszał

The version with będzie się pogarszał would emphasize an ongoing process: if your eyesight is going to be getting worse.
The sentence uses pogorszy się because it focuses on the result: your eyesight becomes worse.

Here się is part of the verb pogorszyć się, which means to become worse.

Compare:

• pogorszyć coś = to worsen something
• pogorszyć się = to get worse, to become worse

So:

• Lekarz pogorszył sytuację = The doctor made the situation worse
• Sytuacja się pogorszyła = The situation got worse

In your sentence:

• wzrok się pogorszy = eyesight will get worse

So się does not mean yourself here in the English sense. It is just part of the reflexive/intransitive form of the verb.

They refer to different things:

• wzrok = eyesight, vision, the ability to see
• oczy = eyes, the physical organs

So:

• wzrok się pogorszy = your eyesight gets worse
• mrużysz oczy = you squint your eyes / narrow your eyes

This is a useful distinction in Polish. Your wzrok can worsen, but you squint your oczy.

Because the sentence mixes two kinds of conditions:

• wzrok się pogorszy = a possible future change
• często mrużysz oczy = a habitual action, something you often do

So the meaning is roughly:

• progressive lenses will help if your eyesight gets worse and you often squint your eyes

The second part describes a recurring symptom or habit, so the present tense is natural.

Polish does this quite comfortably, just like English can.

Because mrużyć is imperfective, and it works well for repeated or habitual actions.

• mrużyć oczy = to squint / to keep narrowing your eyes / to do it repeatedly
• zmrużyć oczy = to squint once, to narrow your eyes as a single completed action

Since the sentence says często = often, Polish naturally uses the imperfective:

• często mrużysz oczy

That means you often squint.

Because Polish usually drops subject pronouns when they are clear from the verb ending.

• mrużysz already means you squint
• the ending -ysz tells us it is 2nd person singular

So ty is unnecessary unless you want emphasis or contrast:

• Ty mrużysz oczy, a ja nie = You squint your eyes, and I don’t

In a normal sentence, just mrużysz is enough.

Because with body parts, Polish often leaves out the possessive adjective when the owner is obvious.

So Polish prefers:

• mrużysz oczy = you squint your eyes
• myję ręce = I wash my hands

Instead of:

• mrużysz twoje oczy
• myję moje ręce

Adding twoje would usually sound emphatic, contrastive, or unnatural in an ordinary sentence.

It is in the accusative plural, because oczy is the direct object of mrużyć.

You are squinting what?

• oczy

So the verb takes an object in the accusative.

In this particular word, the nominative plural and accusative plural have the same form:

• oczy

So the form does not change, but the grammatical role does.

Because jeśli introduces a subordinate clause, and in Polish such clauses are normally separated by a comma.

So:

• Szkła progresywne pomogą, jeśli wzrok się pogorszy i często mrużysz oczy.

This comma is standard Polish punctuation. Even if English punctuation sometimes feels different, in Polish the comma before jeśli is expected here.