Cabin pressure
Could someone tell me what the standard pressurisation is in the cabin, in, for example a 737. I have a friend with an eye problem who has been told she may not be able to fly in two weeks time due to the cabin pressure. I understood that the cabin was not pressurised to ground level pressure, but to something higher, therefore being at a lower pressure than ground level. Is this correct? If so, to what altitude is the cabin pressurised???
Thanks for any help.