Illalla laitan silmätippoja, koska silmät ovat kuivat.

Illalla is the word ilta (evening) with the ending -lla.

In this kind of time expression, -lla/-llä is very common with parts of the day:

• aamulla = in the morning
• päivällä = in the daytime / during the day
• illalla = in the evening
• yöllä = at night

So illalla is just the normal Finnish way to say in the evening.

Finnish often uses the present tense for the future when the time is already clear from context.

So:

• Illalla laitan silmätippoja
  literally looks like In the evening I put/apply eye drops
• but naturally it means I’ll put in/apply eye drops in the evening

Because illalla already shows the time, Finnish does not need a separate future tense form.

Laitan is the 1st person singular present tense of laittaa.

• laittaa = to put, place, apply
• laitan = I put / I will put

In this sentence, laittaa is being used in the sense to apply eye drops.

Some related forms:

• minä laitan = I put
• sinä laitat = you put
• hän laittaa = he/she puts
• me laitamme = we put
• te laitatte = you all put
• he laittavat = they put

Silmätippoja is the partitive plural of silmätipat (eye drops).

The partitive is used here because the sentence is talking about some amount of eye drops, not a complete, clearly counted set.

So:

• laitan silmätippoja = I apply some eye drops
• laitan silmätipat would sound more like I put in the eye drops / I apply the whole intended set, depending on context

This is a very common Finnish pattern: with substances, liquids, or unspecified amounts, the partitive is often used.

Since eye drops are understood as drops/liquid rather than a clearly counted object here, silmätippoja is natural.

The basic form is usually given as silmätippa or more commonly in actual use silmätipat as the everyday word for eye drops.

In this sentence, the form is:

• silmätippoja = partitive plural

A rough pattern is:

• silmätippa = an eye drop
• silmätipat = eye drops
• silmätippoja = (some) eye drops

Learners often meet this word in the plural because in real life we usually talk about eye drops rather than one eye drop.

Finnish often leaves out possessive words like my, your, his/her when they are obvious from context, especially with body parts.

So:

• silmät ovat kuivat = the eyes are dry literally
• but in context it naturally means my eyes are dry

Because the speaker is talking about applying eye drops, it is easy to understand whose eyes are meant.

If you wanted to make it explicit, you could say:

• koska minun silmäni ovat kuivat = because my eyes are dry

But that sounds more explicit than necessary in many everyday situations.

Because both the noun and the adjective are plural here.

• silmät = eyes, plural
• ovat = are, plural form of olla
• kuivat = dry, plural adjective form

Finnish adjectives agree with the noun in number in this kind of sentence.

So the structure is:

• silmä on kuiva = the eye is dry
• silmät ovat kuivat = the eyes are dry

A learner coming from English may forget that Finnish shows plural not just on the noun, but also on the verb and the adjective here.

In this sentence, koska means because.

• Illalla laitan silmätippoja, koska silmät ovat kuivat.
• I’ll put in eye drops in the evening, because my eyes are dry.

Yes, koska can also mean when in some contexts, especially in more formal or literary language, but for most learners the most common meaning to remember is because.

If the sentence has a clear cause-and-effect relationship, koska is understood as because.

Yes, both are possible.

Finnish word order is more flexible than English word order. The version in your sentence puts illalla first to set the time frame right away:

• Illalla laitan silmätippoja = In the evening, I’ll apply eye drops.

You could also say:

• Laitan silmätippoja illalla

That is also correct, but the emphasis shifts slightly. Putting illalla first makes the time more prominent.

So the original sentence sounds very natural, especially if the speaker is organizing their routine or emphasizing when they do it.

Finnish does not have articles like English a/an and the.

So Finnish simply says:

• silmät = eyes / the eyes / my eyes, depending on context
• silmätippoja = eye drops / some eye drops

The exact meaning is understood from the situation, grammar, and context.

This is one of the biggest differences from English: Finnish often leaves things less explicitly marked than English does.

It is the adjective kuiva (dry) in the plural nominative form, matching silmät.

Basic form:

• kuiva = dry

Forms here:

• kuiva silmä = a dry eye
• kuivat silmät = dry eyes
• silmät ovat kuivat = the eyes are dry

So nothing unusual is happening beyond normal agreement: plural noun, plural adjective.

Yes. Depending on context, natural English translations could be:

• put in eye drops
• apply eye drops
• use eye drops

The Finnish verb laittaa is very broad and often means put or place, but with medicine or drops it often corresponds to apply or put in in English.

So in this sentence, laitan silmätippoja is best understood as I’ll put in/apply/use eye drops.

It could be either. Finnish present tense by itself does not force one interpretation.

• If this is part of a daily routine, it can mean In the evening I put in eye drops.
• If the speaker means tonight specifically, it can mean This evening I’ll put in eye drops.

The sentence does not tell you by grammar alone whether it is habitual or one-time. Context would decide.

That flexibility is normal in Finnish.