RESUMO
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.
RESUMO
A prospective study of 32 eyes, undergoing laser refractive surgery, was performed. Routine complete pre-operative evaluation was done. A new device (Ocular Cyclotorsion Measurement Device, OCMD‚ has been used to evaluate the rotation of the eye from the sitting to the supine position. 68.75 % (n = 22) of the eyes had no rotation with the position changes. 15 % (n = 5) had inward rotation and 15% (n = 5) had outward rotation. The range of rotation varied from 5 degrees to 10 degrees. There was no correlation between the degree of nearsightedness or astigmatism with the degree of rotation (R2 =0.037). The rotation of the eye from the sitting to supine position can cause misalignment of the axis of treatment especially cases with astigmatism. Care should be taken when treating cases with high astigmatism.