Microvascular changes in macula and optic nerve head after femtosecond laser-assisted LASIK: an optical coherence tomography angiography study

BackgroundTo measure the microcirculation change of macula and optic nerve head before and after femtosecond laser assisted laser in situ keratomileusis.MethodsIn total 45 eyes from 45 subjects, who underwent FS-LASIK during June 2017 to December 2017 in Guangdong Provincial People's Hospital, were recruited in this study. Vessel density in macula and optic nerve head were measured by optical coherence tomography angiography before and after transient elevation in intraocular pressure caused by application of suction ring during surgery.ResultsVessel density (VD) at superficial (SCP) plexus of macular region did not differ after surgery (F(3,132)=1.41, P=0.24), while the deep (DCP) plexus of macular region significantly decreased 1day after surgery (P=0.001) but returned to its baseline value 1month postoperatively (P=0.1). Vessel density of optic nerve head region had no significant changes after surgery (F(2.51,95.18)=0.6, P=0.59).ConclusionsA short-term temporary decrease of vessel density at deep layer of macular region was observed in eyes undergoing FS-LASIK. However, the retinal capillary density went back to preoperative level 1month after surgery. Therefore, transient IOP spike during FS-LASIK did not cause long-term decline of retinal microcirculation.