Learn Hardcore Finnish: Videopelin näyttöruutu on niin kirkas, että silmiä väsyttää. - The video game’s screen is so bright that the eyes get tired.

Silmät väsyvät.
Literally: The eyes get tired.
This is a normal personal clause: silmät is the subject (nominative plural), and väsyvät is the intransitive verb väsyä (to get tired), conjugated in the 3rd person plural.
Silmiä väsyttää.
Literally: [Something] tires the eyes / the eyes are being tired.
This uses the verb väsyttää, which means to tire / to make tired. Here we have an impersonal/subjectless-like construction: the experiencer (silmiä, “eyes”) is in the partitive plural, and the verb väsyttää is in the 3rd person singular. The “agent” (what causes the tiredness) is understood from context and not repeated.

In this sentence, the main clause already names the cause: Videopelin näyttöruutu on niin kirkas.
So the result clause can be formulated naturally as:

…että silmiä väsyttää.
= …that it tires (your/my/one’s) eyes.

This is an idiomatic way in Finnish to express physical sensations or states caused by something: päätä särkee (one has a headache), korvia kuumottaa (ears burn), selkää särkee (back aches), minua väsyttää (I am tired / something makes me tired).

Why is silmiä in the partitive plural and not silmät?

Silmiä is the partitive plural of silmät (“eyes”). There are two key reasons for the partitive here:

The verb construction:
With verbs like väsyttää, särkeä, huolestuttaa, etc., the experiencer or affected body part normally appears in the partitive case:
- Minua väsyttää. – I’m tired.
- Päätä särkee. – My head aches.
- Käsiä särkee. – My hands ache.
So silmiä väsyttää follows this same pattern.
Plural meaning:
We’re talking about more than one eye → plural. In this pattern, you put the affected part in partitive plural if it’s plural:
- One eye: silmää väsyttää (rarely said, but grammatically okay)
- Both eyes: silmiä väsyttää (natural here)

So the structure “[partitive (often body part)] + väsyttää” is standard and idiomatic.

Who exactly is getting tired? Whose eyes are silmiä?

In normal Finnish, if nothing else is said, it is understood to refer to the speaker’s (or contextually obvious people’s) eyes.

So:

Videopelin näyttöruutu on niin kirkas, että silmiä väsyttää.
is understood as
The video game’s screen is so bright that *(my/our/one’s) eyes get tired.*

If you want to be explicit, you can say:

…että minun silmiäni väsyttää. – so bright that my eyes get tired.
…että hänen silmiään väsyttää. – so bright that his/her eyes get tired.

But in everyday language, the possessive is often omitted when it’s clearly about the speaker or generally about people’s eyes.

What is the difference between väsyttää and väsyä?

They are related but not interchangeable:

väsyä = to get tired (intransitive)
The subject itself becomes tired.
- Minä väsyn helposti. – I get tired easily.
- Silmät väsyvät. – The eyes get tired.
väsyttää = to tire / to make tired; also used to express feel tired in Finnish (transitive/experiencer construction)
It presents the tiredness as something caused by something else.
- Kirkas valo väsyttää silmiä. – Bright light tires the eyes.
- Minua väsyttää. – I’m tired (literally: something tires me).

In the sentence:

Videopelin näyttöruutu on niin kirkas, että silmiä väsyttää.

The idea is:

The bright screen causes the eyes to become tired → väsyttää is the best verb.

Why is there a comma before että?

In Finnish punctuation, you almost always put a comma before the conjunction että when it starts a subordinate clause, even if English would not:

Tiedän, että se on vaikeaa. – I know (that) it is difficult.
Hän sanoi, että tulee myöhemmin. – He/She said (that) he/she will come later.

So:

Videopelin näyttöruutu on niin kirkas, että silmiä väsyttää.

has a comma because että silmiä väsyttää is a full subordinate clause (a result clause).

What does the pattern niin kirkas, että… mean exactly?

The pattern niin + adjective + että + clause is the standard way to say:

“so + adjective + that + clause”

Examples:

Se on niin kallis, että en voi ostaa sitä.
– It’s so expensive that I can’t buy it.
Auto oli niin vanha, että se hajosi matkalla.
– The car was so old that it broke down on the way.

So here:

Videopelin näyttöruutu on niin kirkas, että silmiä väsyttää.
= The video game’s screen is so bright that it makes (my) eyes tired.

niin kirkas = so bright
että silmiä väsyttää = that (one’s) eyes get tired / that it tires the eyes

Why is että used here and not koska or jotta?

The conjunctions have different functions:

että – here introducing a result clause (so … that …):
- Se on niin vaikea, että luovutan. – It’s so hard that I give up.
koska – means because, introducing a reason:
- Luovutan, koska se on niin vaikea. – I give up because it’s so hard.
jotta – means so that / in order that, introducing a purpose:
- Teen harjoituksia, jotta oppisin suomea. – I do exercises so that I would learn Finnish.

In your sentence, the second part is a result of the first, not a reason (explained the other way around) or a purpose:

The screen is so bright → as a result, eyes get tired.
→ niin kirkas, että silmiä väsyttää is correct.

What exactly does Videopelin näyttöruutu mean word by word? Why is videopelin in the genitive?

Let’s break it down:

videopeli = video game
videopelin = genitive form of videopeli
→ of the video game / video game’s
näyttö = screen / display
ruutu = screen / pane / panel
näyttöruutu = compound noun: literally display-screen, essentially monitor / screen.

So:

videopelin näyttöruutu
= the video game’s screen
= the screen of the video game

In Finnish, the possessed item (näyttöruutu) stays in nominative as the head of the noun phrase, and the “owner” (videopeli) is put in genitive (videopelin):

koiran häntä – the dog’s tail
talon ovi – the house’s door
videopelin näyttöruutu – the video game’s screen

That is why videopeli becomes videopelin.

Could you also say videopelin ruutu or pelin näyttö? Is there any difference?

Yes, these are possible, but the nuance or specificity changes slightly:

videopelin näyttöruutu
– very clear: specifically the display screen used for the video game.
Could be a monitor, TV screen, handheld screen, etc.
videopelin ruutu
– literally “the video game’s screen”. This can sound a bit more like the image / screen view provided by the game, not necessarily the physical device.
pelin näyttö
– “the game’s display”. Also understandable, maybe more technical-sounding or less specific than näyttöruutu.

In everyday language, näyttöruutu or just näyttö (“screen/monitor”) is normal. The given phrase is quite natural Finnish.

In että silmiä väsyttää, why isn’t the subject repeated (like että se väsyttää silmiä)?

It could be repeated, but it doesn’t have to be.

The “subject” or cause is already clear from the main clause:

Videopelin näyttöruutu on niin kirkas, että [se] väsyttää silmiä.

Grammatically, this is fine:

…että se väsyttää silmiä. – …that it tires the eyes.

However, Finnish often omits a subject that is obvious from context, especially in impersonal-like result clauses. So:

…että silmiä väsyttää.

is more compact and still perfectly clear. The listener naturally links väsyttää back to videopelin näyttöruutu as the cause.

Why is väsyttää in the third person singular if the eyes are plural?

In the construction [partitive experiencer] + väsyttää, the verb form does not agree with the experiencer in number, because the experiencer is not the grammatical subject.

Compare:

Silmät väsyvät. – Eyes get tired.
- Subject: silmät (nominative plural)
- Verb: väsyvät (3rd person plural) → agreement.
Silmiä väsyttää. – (Something) tires the eyes.
- Silmiä is in partitive plural, functioning as the object/experiencer, not the subject.
- The verb väsyttää appears in 3rd person singular, as usual in this pattern.

You see this with many similar verbs:

Päätä särkee. – (My) head aches.
Selkää kolottaa. – (My) back aches.
Minua paleltaa. – I feel cold.

The verb is always 3rd person singular in these idiomatic experiencer constructions.

Is the present tense väsyttää used only for “right now,” or can it mean a general or future effect too?

Finnish present tense is quite flexible. It can express:

Current state or event:
- Silmiä väsyttää. – My eyes are getting tired / feel tired now.
General truth or tendency:
- Kirkas valo väsyttää silmiä. – Bright light tires the eyes (in general).
Near future, when context shows it:
- Huomenna me mennään. (present form) – We’re going tomorrow.

In your sentence:

Videopelin näyttöruutu on niin kirkas, että silmiä väsyttää.

it can describe:

a current situation (right now the eyes are getting tired),
or a general effect (whenever you play, its bright screen makes your eyes tired).

Context decides which nuance is intended; the grammar is the same.

Could the word order be että väsyttää silmiä instead of että silmiä väsyttää?

Yes, you can say:

Videopelin näyttöruutu on niin kirkas, että väsyttää silmiä.

This is still correct Finnish. The difference is subtle:

että silmiä väsyttää
– Starts the clause with what is affected (silmiä), which slightly emphasizes the eyes.
että väsyttää silmiä
– Starts with the verb, sounding a bit more impersonal or general (“it tires the eyes”).

Both are fine; Finnish word order is quite flexible, as long as sentence structure and case endings are clear.

Why use kirkas and not some other word like valoisa?

kirkas and valoisa are related but not identical:

kirkas
– bright, intense (in light), clear
Often used for:
- light sources: kirkas lamppu – bright lamp
- screens: kirkas näyttö – bright display
- sounds, colors, weather, etc.
valoisa
– light, well-lit (about places or environments)
- valoisa huone – a bright (well-lit) room
- valoisa keittiö – a light kitchen

Since we’re talking about the brightness of a screen, kirkas is the most natural word.
Valoisa näyttöruutu would sound odd, as if the screen itself were like a “well-lit room” rather than emitting bright light.