Внутриглазное давление и поле зрения измерили.

Because together they form a coordinated pair: внутриглазное давление и поле зрения = intraocular pressure and visual field. Russian uses a plural verb with two items joined by и.

So even though each noun is singular by itself, the whole phrase is grammatically plural in meaning.

Also, in this sentence there is another layer: измерили can imply an omitted they. So the plural can also be understood as they measured.

There is no explicit subject here. Russian very often leaves out an indefinite plural subject when English would say they or use the passive.

So:

• Внутриглазное давление и поле зрения измерили. can mean literally They measured the intraocular pressure and the visual field.

But in English, especially in medical style, this is often translated more naturally as:

• The intraocular pressure and visual field were measured.

This is a very common Russian pattern.

Formally, they are ambiguous here.

That is because for inanimate neuter nouns, the nominative and accusative forms are the same:

• давление = nominative or accusative
• поле = nominative or accusative

So from the forms alone, you cannot tell whether they are the subject or the direct object.

In real usage, this sentence is usually understood as an indefinite-personal active sentence:

• [They] measured intraocular pressure and visual field.

English often renders that as a passive:

• Intraocular pressure and visual field were measured.

So grammatically in Russian, these words are most naturally understood as the direct object of an omitted they.

Because внутриглазное agrees with давление.

The noun давление is:

• neuter
• singular
• here either nominative or accusative

So the adjective must match that:

• внутриглазный — masculine
• внутриглазная — feminine
• внутриглазное — neuter
• внутриглазные — plural

Since the head noun is давление, the correct form is внутриглазное.

Зрения is the genitive singular of зрение.

So:

• поле зрения literally means field of vision
• this is a normal noun + genitive pattern in Russian

It works like:

• центр города = city center
• чашка чая = cup of tea
• поле зрения = field of vision

In other words, зрения depends on поле and specifies whose/what field it is.

Измерили is the perfective past form of измерить.

Perfective is used because the sentence presents the action as completed:

• the measuring was done
• the result is relevant

In a medical record or report, that is very natural.

Compare:

• измерили = measured, completed
• измеряли = were measuring / measured repeatedly / used to measure

Here the perfective says, essentially: the measurement was carried out.

Russian word order is flexible, so the sentence does not have to follow English-style subject-verb-object order.

Putting the verb at the end is common in:

• reports
• notes
• medical or formal writing

Here, the important information comes first:

• Внутриглазное давление и поле зрения — the things being discussed

Then the action comes at the end:

• измерили

This can sound concise and natural in clinical or written contexts.

Yes. Russian often prefers the active plural-without-subject pattern, but a more explicitly passive version is possible, for example:

• Внутриглазное давление и поле зрения были измерены.

That is closer to a direct English passive: were measured.

Still, the original sentence with измерили is very common and idiomatic, especially in brief factual statements.

Because Russian has no articles like a, an, or the.

So внутриглазное давление и поле зрения can mean:

• intraocular pressure and visual field
• the intraocular pressure and the visual field

The exact interpretation comes from context, not from articles.

It is complete and natural, but it does sound somewhat like medical record or report style because it is short and matter-of-fact.

In more conversational Russian, a speaker might add more context, for example:

• Пациенту измерили внутриглазное давление и поле зрения.
• Ему измерили внутриглазное давление и поле зрения.

But as a stand-alone sentence in a clinical context, the original version is perfectly normal.