ABSTRACT
Objective To investigate the spherical diopter and astigmatism change of humans at sitting and supine position.De- sign Prospective case series.Participants 96 eyes of 52 patients (spherical diopter from-2.50 D to-10.00 D,astigmatism diopter from -0.75 D to-4.50 D) were selected.Methods The subjects were examined with NIKON portable retinomax at sitting and supine posi- tion,respectively.Main Outcome Measures The spherical diopter,cylinder diopter and axis change were analyzed statistically.Re- sults Spherical diopter at supine position (-5.31?3.43 D) was a little higher than that at sitting position (-5.27?3.24 D) statistically(P= 0.25),and cylinder diopter at sitting position (-2.27?1.24 D) and at supine position (-2.35?1.19 D) was no statistically difference (P= 0.20).The axis of astigmatism changed from-16?to +18?.Axis change was within 2?in 52.1% eyes,6?-10?in 5.2%,over 10?in 3.1%. The change of axis rotation tended to counter-clockwise in the right eye and clockwise in the left eye.Conclusions Eye rotation at sit- ting and supine position may cause the astigmatism axis change.It may be one of the main factors affecting the results of LASIK.