Re: Raised intraocular pressure and perioperative visual loss in laparoscopic colorectal surgery: a catastrophe waiting to happen? A systematic review of evidence from other surgical specialties.

摘要

I read with interest the recent review by Pinkney et al. [1] identifying the highest risk of postoperative visual loss (POVL) as attributable to steep head-down and/or prone positions (such as jackknife).Ischaemic optic neuropathy (ION) is the most important diagnostic feature of POVL [2]. Although it is not clear what the precise mechanism that leads to ION is, an increase in intraocular pressure (IOP) is the most likely explanation [3]. The accepted view that ophthalmic circulatory autoregula-tion prevents elevation in IOP and maintains ocular perfu-sion pressure (OPP) has been challenged in patients undergoing surgery in a steep head-down position. Several studies have established that positioning patients in such a way causes a rise in IOP and consequently impairment of OPP [4].