Correlation Analysis Of Refractive Regression After Laser In Situ Keratomileusis

ObjectiveThe aim of this study was to investigate the relationship between various factors and refractive regression of high myopic subjects who underwent laser in situ keratomileusis (LASIK) over one year ago. The patients were followed up and examined by confocal microscope through focusing(CMTF).We analyzed the reseans of refractive regression at the cellular level.Subjects MethodsThe study was a retrospective analysis of 66 eyes of 35 subjects (mean preoperative refraction -8.53?.82D) who underwent LASIK from October 2001 to August 2002 and had refractive regression . We analyzed uncorrected visual acuity(UCVA) , best corrected visual acuity(BCVA) . spherical equivalentrefraction intraocular pressure comeal curvature corneal pachymetry ofpreoperation and UCVA . intraocular pressure corneal curvature . cornea pachymetry of postoperation. All patients were examined by CMTF.Reuslts1 .Refractive regression was negatively correlated with the amount of change in corneal curvature. No significant correlation was found between regression and corneal curvature of preoperation and postoperation.2.There was no correlation between regression and intraocular pressure.3.A negative correlation was found between regression and the amount of change in central pachymetry. Regression had not correlation with central pachymetry of preoperation and postoperation .-4-20014.The thickness of corneal epithelium of the 66 eyes (44.70 ?2.66Mm) and the control group(41.74 ?5.86) were compared, no significant differences were observed.There were significant differences between the stromal thickness and the control group. The number of the most anterior keratocytes were 704.50 ?35.9cells/mm2, the control group were 1087.0?7.0cells/mm2, the differences were statistically significant.S.Acellular zone and interface particles were observed in all patients.Microfolds and high-reflection zone were observed in some patients.Conclusion1 .There was negative correlation between refractive regression and the amount of change in corneal curvature.. The change of corneal curvature may be caused by increase of stromal thickness, which produced regression.2.Refractive regression was not correlated with intraocular pressure.3.Refractive regression was not correlated with epithelial hyperplasia, but correlated with the increase of stromal thickness. Loss of the most anterior keratocytes and apoptosis may be responsible for the increase of stromal thickness .4.Microfolds acellular zone and interface particles were present for a long time postoperatively.