Otkad sam očistila zaslon, lakše čitam sve što piše na njemu.

Here otkad means since or ever since.

So Otkad sam očistila zaslon means Since I cleaned the screen / Ever since I cleaned the screen.

It introduces a starting point in the past, and the main clause describes a situation that has been true from that point up to now.

They are very close in meaning. Both can mean since or from when.

In this sentence, otkad is the natural compact form. A learner should recognize that:

• otkad = one-word form, very common
• od kada = two-word form, also possible in many contexts

Here, otkad sounds perfectly normal and idiomatic.

This is the Croatian perfect tense, formed with:

• the auxiliary sam = I am / have as a clitic auxiliary
• the past participle očistila

So sam očistila means I cleaned / I have cleaned, depending on context.

In this sentence, it refers to a completed action in the past: first the speaker cleaned the screen, and now the result is that reading is easier.

Because the past participle agrees with the speaker’s gender.

• očistila = feminine singular
• očistio = masculine singular

So this sentence was said by a female speaker.
If a male speaker said it, it would be:

Otkad sam očistio zaslon, lakše čitam sve što piše na njemu.

Because sam is a clitic, and Croatian clitics usually go near the beginning of the clause, often in the second position.

So in:

Otkad sam očistila zaslon...

the conjunction otkad comes first, and the clitic sam comes right after it.

This word order is very typical in Croatian and may feel unusual to English speakers at first.

Because Croatian usually drops subject pronouns when they are already clear from the verb form.

Here, the sentence already shows first person singular through:

• sam očistila = I cleaned
• čitam = I read / am reading

So ja is not needed.

You could add ja for emphasis, but the neutral version usually leaves it out.

Yes. Zaslon means screen or display.

In this sentence it clearly means the screen of some device, such as a phone, tablet, or computer.

You may also hear ekran, which is another common word for screen.
Both exist, but zaslon is a very standard Croatian word.

Lakše is the comparative adverb of lako.

• lako = easily
• lakše = more easily

So lakše čitam means I read more easily.

It is an adverb here because it modifies the verb čitam.

An English speaker may expect something like better, but Croatian uses lakše very naturally for more easily.

Sve što means everything that or all that.

Breakdown:

• sve = everything / all
• što = that / what

So:

sve što piše na njemu = everything that is written on it

This is a very common Croatian structure. For example:

• Sve što znam = Everything I know
• Sve što želiš = Everything you want

Because Croatian often uses piše to mean it says or it is written.

So što piše na njemu does not mean someone is actively writing on it right now.
Instead, it refers to what appears there as text.

In English, we might naturally say:

• everything that is written on it
• everything that appears on it
• everything it says

But Croatian often uses the simple present piše in this kind of context.

Njemu is in the locative case, used here after na to show location.

• na + locative = on / at a place
• na + accusative = movement onto something

Here the meaning is location: the text is on the screen, so we get:

na njemu = on it

Also, njemu refers back to zaslon, which is a masculine noun.
That is why it is njemu and not njoj or njemu/nje in some other form.

Because Otkad sam očistila zaslon is a subordinate clause, and Croatian normally separates it from the main clause with a comma.

So the structure is:

• subordinate time clause: Otkad sam očistila zaslon
• main clause: lakše čitam sve što piše na njemu

This is standard Croatian punctuation.

The sentence combines:

• a completed past action: sam očistila
• a present situation/result: čitam

So the idea is:

1. I cleaned the screen.
2. Since then, reading what is on it has been easier.

This is a very common pattern after otkad: a past event marks the starting point, and the main clause describes what is true now as a result.