Gerbil,
Standard computer monitors (CRT's) and televisions have been problematic for the last 15 years, along with prolonged exposured to fluorescent lights. I get very irritable and anxious after an hour or two, then all tired out.

Since switching to an LCD monitor this year, it's been a bit less fatiguing...still I have to be careful.

Balance versus dizziness: I have more balance issues than outright dizziness, especially upon awakening and at bedtime. Some transient vertigo spells no matter what I'm doing; usually they are shorter in duration than they used to be. Part of the balance issue for me is something called proprioception: I have difficulty understanding where my body is in space. Massage and accupuncture have helped quite a bit over the years, but that which remains I've come to take for granted and watch where I walk!

Hope you get some answers from the balance testing.

Best,
Jeff