What is the difference of pressure a human eyeball cornea (cornea, lens and other elements separating vitreous body from air) can handle? Or asking differently: what the outside pressure should be to "blow up" a healthy man's eyeball?
Normal pressure in the eye1,2 is between 10 and 21 mmHg (somewhere around 1.3-2.8 kPa or 0.01-0.03 atm) with pathology occurring at around 30 mmHg.3 Clearly the cornea can handle that, but how much more? There's a lot more evidence as far as I could see for how well surgeries hold up, with 150-300+ mmHg (20-40 kPa, 0.2-0.4 atm).4 One source5 from 1998 cites work supposedly showing that the stroma:
So maybe around 200 kPa, for just the stroma? Interestingly, a new eye layer was discovered earlier this year; this Dua's Layer is incredibly thin - 15 microns - but can withstand pressures of around 100-200 kPa (750-1500 mmHg, 1-2 atm).6,7 The large range there is due to some conflicting numbers in those links; the 200 kPa is the more widely reported one, but again, that's just for one layer.
Then, of course, there is this: a beautiful 2009 thesis by Jill Aliza Bisplinghoff from Virginia Tech which thoroughly examines the issue. As an answer to your question, it includes the following such gems: