ازدواج الرؤية وتشوش الرؤية مشكلتان.

In a present-tense nominal sentence, Arabic usually leaves out the verb to be.

So:

ازدواج الرؤية وتشوش الرؤية مشكلتان

literally looks like:

double vision and blurred vision two problems

but it means:

Double vision and blurred vision are two problems.

This is completely normal in Modern Standard Arabic. If the sentence were in the past or future, Arabic would usually use a verb such as كان.

Because the sentence is talking about exactly two things:

• ازدواج الرؤية
• تشوش الرؤية

Arabic has a special form for exactly two items, called the dual. English does not have this, so English just says two problems, but Arabic can build the number two directly into the noun.

So:

• مشكلة = a problem
• مشكلتان = two problems

Here, the predicate is dual because the subject consists of two coordinated items.

Because this word is in the nominative case, and the dual nominative ending is ـتانِ for a noun like مشكلة.

So:

• مشكلة = one problem
• مشكلتانِ = two problems, nominative
• مشكلتينِ = two problems, accusative or genitive

In this sentence, مشكلتان is the predicate of a nominal sentence, so it is nominative.

Both are iḍāfa constructions, often called a construct phrase.

That means:

• ازدواج الرؤية = doubling of vision / double vision
• تشوش الرؤية = blurring of vision / blurred vision

In an iḍāfa:

1. the first noun comes first
2. the second noun explains or specifies it
3. the second noun is in the genitive
4. the whole phrase can become definite if the second noun is definite

So الرؤية makes each whole phrase specific.

Because in an iḍāfa, the first noun normally does not take الـ.

So Arabic says:

• ازدواج الرؤية
• تشوش الرؤية

not:

• الازدواج الرؤية
• التشوش الرؤية

The definiteness comes from the second word, الرؤية. Since الرؤية is definite, the whole phrase is definite.

This is a very common pattern in Arabic and often feels unusual to English speakers at first.

Because these are two separate phrases:

• ازدواج الرؤية
• تشوش الرؤية

Each noun needs its own complement in this structure. Arabic often repeats the second part for clarity, especially in formal or medical language.

So the sentence is built as:

• double vision
• and blurred vision
• are two problems

Repeating الرؤية makes both terms fully clear and parallel.

No. Here they are nouns, more specifically abstract nouns or verbal nouns.

They name conditions or states:

• ازدواج = doubling / duplication
• تشوش = blurring / disturbance / confusion

So the sentence is not verbal. It is a nominal sentence made of noun phrases plus a predicate.

A fully vocalized version would be:

ازدواجُ الرؤيةِ وتشوُّشُ الرؤيةِ مشكلتانِ

A grammatical breakdown:

• ازدواجُ: nominative
• الرؤيةِ: genitive, because it is the second part of the iḍāfa
• وتشوُّشُ: also nominative
• الرؤيةِ: genitive again
• مشكلتانِ: dual nominative predicate

In careful reading, those endings matter grammatically, even though in normal printed Arabic they are usually omitted.