Effects of altitude hypoxia and rapid decompression on the stability of the corneal flap after LASIK in rabbits

Abstract

Objective To study the effect of altitude hypoxia and rapid decompression on the stability of the corneal flap after laser in situ keratomilersis (LASIK) in rabbits.Methods In an experimental study,36 eyes (18 Japanese white rabbits) were randomly divided into 3 groups 1 week after LASIK surgery:the control group,the altitude hypoxia group,and the rapid decompression group.The altitude hypoxia group ascended to 5500 m at the rate of 30-40 m/s remained there for 1-2 min,then returned to ground level at the rate of 200 m/s.The rapid decompression group ascended to 5500 m at the rate of 30-40 m/s,remained there for 1-2 min,then ascended rapidly to an altitude of 12 000 m in 0.13 s by adjusting a pressure-releasing device,remained at the high altitude of 3-5 s,finally returning to ground level at the rate of 200 m/s.The stability of the corneal flap was observed with an optical microscope and transmission electron microscope (TEM).The stability of the corneal flap was analyzed by a x2 test.Results The images under the optical microscope and TEM showed that the interface tissue healing between the flap and stromal bed was clear with no separation,and was surrounded by regular collagen fibers in both the altitude hypoxia and rapid decompression groups.The differences between the two groups and the control group were insignificant (x2=0.22,P＞0.05; x2=0.25,P＞0.05).Conclusion Both altitude hypoxia and rapid decompression do not impact on the stability of corneal flaps after LASIK in rabbits. Key words: Rapid decompression; Altitude hypoxia; Corneal flap; Keratomileusis,laser in situ; Rabbits