What could this vision problem be ? (details inside)

I have refrained from mentioning this before, but many of the symptoms you describe fit those of brain tumors. Two members of my family had them, both benign luckily, but they did require serious surgery.

Acoustic neuroma

Meningioma

My best friends’ brother died from a benign brain tumor. The following year , she died when the cancer went to her brain.
Symptoms (Mayo Clinic)
New onset or change in pattern of headaches—none.
Headaches that gradually become more frequent and more severe-none.
Unexplained nausea or vomiting-never.
Vision problems, such as blurred vision, double vision or loss of peripheral vision-yes.
Gradual loss of sensation or movement in an arm or a leg-no.
Difficulty with balance-no.
Speech difficulties-no.
Confusion in everyday matters-no.
Personality or behavior changes-no.
Seizures, especially in someone who doesn’t have a history of seizures-no.
Hearing problems-tinnitus since ‘09 when the dogs began barking at passersby in my office.