Changes of the thinnest corneal point before and after laser in situ keratomileusis using a pentacam system

Objective To explore the change of the position of the thinnest corneal point before and after LASIK with the pentacam measurement to provide the reference for the surgery design.Methods The position of the thinnest corneal point and the distance from the thinnest corneal point to the corneal vertex of 70 cases (140 eyes) were measured with the Pentacam before and 3 months after LASIK.The results were compared.Results The distance from the thinnest corneal point to the corneal vertex was 0.617±0.188mm before LASIK and 0.359±0.162mm 3 months after LASIK,there was a significant between two measurement results (P ＜0.001),the distance from the thinnest corneal point to the pupil center was 0.656±0.188mm before LASIK and 0.303±0.155mm 3 months after LASIK,there was also a significant between two measurement results (P ＜0.001).The thinnest point of cornea was mostly located in the inferotemporal of the comeal vertex according for 84.29％ before LASIK and according for 51.43％ after LASIK.it moved to the superonasal of 0.258 ± 0.187mm based on the comeal vertex and it moved to the superonasal of 0.353±0.208mm based on the pupil center,there was a significant differences between the two sets of results (P＜0.001).Conclusions The thinnest point of cornea is located in the corneal vertex and pupil center's inferotemporal before and after LASIK.The thinnest point of cornea is closer to the corneal vertex than the pupil center before LASIK,but it is closer to the pupil center than the corneal vertex after LASIK.The thinnest point of cornea trends to move the superonasal after LASIK. Key words: Cornea ;  Pupil ;  Laser in situ keratomileusis ;