Die optometris meet die pupilafstand vir die brillense.

Die is the Afrikaans definite article, meaning the.

So:

• die optometris = the optometrist
• die pupilafstand = the pupil distance
• die brillense = the glasses lenses / spectacle lenses

Afrikaans uses die for:

• singular nouns
• plural nouns
• all genders

So unlike in some other languages, you do not have to learn different forms such as masculine, feminine, or neuter articles.

No. In this sentence, meet means measures.

That can be confusing for English speakers because it looks like the English word meet. In Afrikaans:

• meet = measure
• ontmoet = meet someone

So:

• Die optometris meet die pupilafstand = The optometrist measures the pupil distance
• Ek ontmoet die optometris = I meet the optometrist

Pupilafstand is a compound noun. Afrikaans often joins nouns together into one word.

It is made up of:

• pupil = pupil
• afstand = distance

So pupilafstand literally means pupil distance.

This is very common in Afrikaans. Where English may sometimes use two words, Afrikaans often prefers one compound word.

Vir usually means for.

Here, vir die brillense means for the spectacle lenses or for the glasses lenses. It shows what the measurement is intended for.

So the sentence means that the optometrist is measuring the pupil distance for making or fitting the lenses properly.

Brillense is the plural of brillens.

It is made from:

• bril = glasses / spectacles
• lens = lens

So:

• brillens = spectacle lens / eyeglass lens
• brillense = spectacle lenses / eyeglass lenses

A learner may also know brille, which means glasses as a whole pair.
So there is a difference:

• brille = glasses
• brillense = the lenses of the glasses

Yes. This is a normal main-clause word order in Afrikaans:

• Die optometris = subject
• meet = verb
• die pupilafstand = object
• vir die brillense = prepositional phrase

So the structure is basically:

Subject + Verb + Object + Prepositional phrase

That is very similar to English: The optometrist measures the pupil distance for the lenses.

Yes, it is related in meaning to measure.

Meet is pronounced roughly like mate in English, but with a clear long vowel typical of Afrikaans.

So it does not sound like English met.
It sounds closer to:

• meet → approximately mate

This is one reason English speakers can misread it at first.

Afrikaans often uses the simple present where English might use either the simple present or the present continuous.

So:

• Die optometris meet die pupilafstand can mean
  The optometrist measures the pupil distance
  or, depending on context,
  The optometrist is measuring the pupil distance

Afrikaans does have ways to emphasize an ongoing action, but in many ordinary sentences the simple present is enough.

Afrikaans nouns do not have grammatical gender in the same way that many European languages do.

So optometris is simply optometrist, and the article stays die regardless of whether the person is male or female.

If needed, context tells you the person’s gender, not the noun form itself.

Yes. In a more technical or optometry-related context, pupilafstand is often best translated as pupillary distance.

So possible translations are:

• pupil distance
• pupillary distance

Both are acceptable, but pupillary distance is the more technical English term.

The sentence is understandable and natural enough, especially in a learning context.

However, speakers might also say similar things such as:

• Die optometris meet die pupilafstand vir die bril.
• Die optometris meet my pupilafstand vir die lense.

The exact wording can vary depending on whether the focus is on:

• the glasses as a whole
• the lenses specifically
• the patient’s own pupil distance

But the grammar of the given sentence is perfectly learnable and clear.