Synsstyrken og synsfeltet måles.

In Norwegian, definiteness is usually shown by adding an ending to the noun instead of putting a separate word before it.

So:

• synsstyrken = the visual acuity
• synsfeltet = the visual field

The endings -en and -et are doing the job that the does in English.

Because the sentence is talking about those specific things as part of an examination or procedure, not just the concepts in general.

In medical or technical language, Norwegian often uses the definite form for things that are being checked, tested, or discussed as identifiable items.

So this sounds like:

• the patient’s visual acuity
• the patient’s visual field

A more generic version such as Synsstyrke og synsfelt måles is also possible in some contexts, but the definite version sounds very natural in clinical or procedural language.

Because the nouns have different grammatical genders.

• synsstyrke is usually treated as a common gender noun in Bokmål, so the definite singular is synsstyrken
• synsfelt is a neuter noun, so the definite singular is synsfeltet

So the endings reflect gender:

• common gender definite singular: -en
• neuter definite singular: -et

Yes. Måles is the present passive form of måle.

• måle = to measure
• måles = is measured / are measured

This -s passive is very common in formal, technical, and written Norwegian.

A similar alternative would be:

• blir målt

Both can express passive meaning, but måles often sounds a bit more concise and formal.

Because Norwegian verbs do not change form depending on whether the subject is singular or plural.

So Norwegian does not do this:

• English: is measured / are measured
• Norwegian: måles / måles

The verb stays the same no matter how many things are involved.

That means måles works with:

• one thing
• two things
• several things

That s is a linking s, which often appears in Norwegian compound nouns.

These words are compounds:

• syn
  • styrke → synsstyrke
• syn
  • felt → synsfelt

The extra s helps link the parts together. It does not usually have a meaning of its own; it is just part of how many compounds are formed.

Not all compounds use a linking s, but it is very common.

Yes. A natural active version would be:

• Man måler synsstyrken og synsfeltet.

That means something like One measures the visual acuity and visual field or more naturally The visual acuity and visual field are measured.

The passive version Synsstyrken og synsfeltet måles is often preferred in formal, medical, or instructional language because it sounds objective and focuses on the procedure rather than on who performs it.

It can cover both, depending on context.

In Norwegian, the present passive often has a broader range than English:

• are measured as a general fact or routine
• are being measured in the current situation

In a sentence like this, without extra context, it often sounds like a general procedural statement: this is something that gets measured as part of the examination.

In Norwegian, when two coordinated nouns are both definite, each noun usually shows definiteness itself.

So:

• synsstyrken og synsfeltet

not a structure where only the first noun carries definiteness for both.

This is normal Norwegian grammar. Each noun is standing as its own definite noun phrase within the coordination.

In Bokmål, synsstyrken is completely normal and standard.

Because synsstyrke is historically a feminine noun, some speakers or varieties may prefer a feminine definite form in other cases with similar nouns, but in standard Bokmål, using -en here is very common and natural.

So for a learner, synsstyrken is the form to recognize and use unless you are specifically studying feminine noun patterns in more detail.