IOP rise during simulated flight

Abstract

Michael Mills and colleagues described a considerable rise in intraocular pressure (IOP) during simulated air travel in patients harboring intraocular gas in their recent article (Ophthalmology 2001;108:40–4). They conclude that conservative recommendations against air travel for patients with intraocular gas bubbles should be heeded. Unfortunately, in their discussion, the authors neglect to mention that the presence of a scleral buckle in such eyes might very likely alter their results.In “Scleral Buckling and Ocular Rigidity: Clinical Ramifications” (Arch Ophthalmol 1990;108:1622–7), Stuart Fourman and I demonstrated that in human eye bank eyes, the presence of an encircling buckle greatly reduces the ocular rigidity. This reduction can approach an order of magnitude if the buckle is high. Furthermore, the reduction has little to do with the elasticity of the encircling element.The fact that ocular rigidity can be substantially reduced after buckling should not be ignored or obfuscated. The authors erroneously reference Pemberton (their reference 16; Arch Ophthalmol 1969;60:534–7) when they state that “cryotherapy decreases ocular rigidity.” On careful reading of the Pemberton article, none of the 115 eyes studied in that article had been treated with cryotherapy. In point of fact, eyes treated with cryotherapy were specifically excluded. Pemberton’s series included only eyes that had undergone scleral buckling and diathermy, and the buckles were believed to play the salient role in altering the Schiøtz tensions compared with results from applanation tonometry.I do not suggest that a patient with intraocular gas bubble who has had scleral buckling is not at risk of an IOP rise during air travel. However, there is precious little published research on buckled eyes during air travel. Lincoff (their reference 7; Arch Ophthalmol 1989;107:907–10) studied rabbits during their simulated ascent in a pressure chamber, but only two were buckled. I know of no human in vivo simulated flight experiments regarding buckled and gas-tamponaded eyes. Buckling may well modulate IOP rises during air travel, as we pointed out in our article written some 10 years ago. I await further work by Mills and his colleagues using patients who have already undergone scleral buckling. Such research has relevance both for patients wanting to travel by air after eye surgery, but also for patients in whom expanding intraocular gasses are placed. Michael Mills and colleagues described a considerable rise in intraocular pressure (IOP) during simulated air travel in patients harboring intraocular gas in their recent article (Ophthalmology 2001;108:40–4). They conclude that conservative recommendations against air travel for patients with intraocular gas bubbles should be heeded. Unfortunately, in their discussion, the authors neglect to mention that the presence of a scleral buckle in such eyes might very likely alter their results. In “Scleral Buckling and Ocular Rigidity: Clinical Ramifications” (Arch Ophthalmol 1990;108:1622–7), Stuart Fourman and I demonstrated that in human eye bank eyes, the presence of an encircling buckle greatly reduces the ocular rigidity. This reduction can approach an order of magnitude if the buckle is high. Furthermore, the reduction has little to do with the elasticity of the encircling element. The fact that ocular rigidity can be substantially reduced after buckling should not be ignored or obfuscated. The authors erroneously reference Pemberton (their reference 16; Arch Ophthalmol 1969;60:534–7) when they state that “cryotherapy decreases ocular rigidity.” On careful reading of the Pemberton article, none of the 115 eyes studied in that article had been treated with cryotherapy. In point of fact, eyes treated with cryotherapy were specifically excluded. Pemberton’s series included only eyes that had undergone scleral buckling and diathermy, and the buckles were believed to play the salient role in altering the Schiøtz tensions compared with results from applanation tonometry. I do not suggest that a patient with intraocular gas bubble who has had scleral buckling is not at risk of an IOP rise during air travel. However, there is precious little published research on buckled eyes during air travel. Lincoff (their reference 7; Arch Ophthalmol 1989;107:907–10) studied rabbits during their simulated ascent in a pressure chamber, but only two were buckled. I know of no human in vivo simulated flight experiments regarding buckled and gas-tamponaded eyes. Buckling may well modulate IOP rises during air travel, as we pointed out in our article written some 10 years ago. I await further work by Mills and his colleagues using patients who have already undergone scleral buckling. Such research has relevance both for patients wanting to travel by air after eye surgery, but also for patients in whom expanding intraocular gasses are placed. IOP rise during simulated flight: Author replyOphthalmologyVol. 108Issue 11Preview Full-Text PDF