Before my eye was removed the 'pumps' that alter the pressure inside the eye - usually to compensate for atmospheric pressure, etc - weren't working properly/at all at times and so the pressure sometimes went up VERY high for certain periods.
Two incidents stand out. The first went on for around 4 hours and literally bleached my perception of vision from the non-blind eye, had me in cold-sweats like you wouldn't believe and 'on my back' but arched completely from heel to crown.
White Pain.
That incident led to my insta-prescriptions for constant, massive doses (1000mg/tablet+) of ibuprofen with a side order of potent, unadulterated codeine (I'm not saying the dose, but enough for me to get quite addicted very quickly) for the really painful times.
The second, I was in work... mid-meeting and blinding, debilitating agony suddenly struck. Tears streaming down my face from the eye, energy and control sucked out of my limbs, I couldn't even talk. I had to, literally, bolt up immediately, stagger/stumble/feel/run out, get home (10 mins walk, 3 mins run) and take enough codeine to help me through it... 6 hours later it was over.
A normal pressure for an eye is, iirc, around 11 (the units are within google-reach but i can't be bothered.
). The day before i had the eye removed the measure was up to 54... but wasn't painful.
These were just the most extreme events... I was in chronic 'normal'/cope-able levels of pain all the time.
When I related my tale of agonies to the doctor, he says the pressure in my eye was probably up toward the point of exploding. Literally.
That would have been pretty.
:s