Analysis Of Intraocular Pressure Changed After SBK And Discussion Of The Related Factors In Anterior Segment Of Eye

Objective:To analyze the anterior segment of myopia eyes after Sub-bowman keratomileusis-SBK in YANAN,and discuss the related factors of intraocular pressure changes. Methods: 1.Randomly choose patients of Yanan university hospital excimer laser myopia correct center treated by SBK surgery from January to November in 2013. The clinical data of 342 eyes are retrospectively analyzed. LUMENIS pentacam made in Germany is used to measure the corneal parameters,and Non-contact Tonometer(Kowa KT-500 Japan) is used to measure the intraocular pressure before and after SBK surgery. Data include CCT、SCC、PCC、e、Q-value and NCT. Using SPSS 21.0 to compare the changes of the data before and after SBK surgery; then compare CCT、SCC、PCC、e and Q-value with the NCT separately. All the data will be under t test and simple linear correlation analysis.2.On the basis of the previous research,anterior chamber parameters select by LUMENID pentacam include ACD、ACA、ACV are analyzed. SPSS 21.0 is used to compare the changes of the data before and after SBK surgery;then compare ACD、ACV、and ACA with the NCT separately. All the data will be under t test and simple linear correlation analysis. Results:1.The parameters of anterior segment of 342 eyes are mainly as follows:The preoperative data value of CCT is(545.40±30.02)um, and the postoperative data value is(456.76±43.85)um. The difference has statistical significance(t=48.83,P<0.001).The preoperative data value of SCC is(43.19±2.70)D, and the postoperative data value is(38.47±2.94)D. The difference has statistical significance(t=46.01,P<0.001).The preoperative data value of PCC is(-6.26±0.20)D, and the postoperative data value is(-6.00±1.64)D.The difference has no statistical significance(t=-1.21,P>0.05).The preoperative data value of e is(0.44±0.16), and the postoperative data value is(-0.78±0.46).The difference has statistical significance(t=49.81,P<0.001).The preoperative data value of Q is(-0.22±0.12), and the postoperative data value is(0.81±0.65).The difference has statistical significance( t=16.09,P<0.001).The preoperative data value of ACD is(3.30±0.21)um,and the postoperative data value is(3.20±0.21)um,The difference has statistical significance(t=23.34,P<0.001).The preoperative data value of ACV is(202.82±23.30)mm3,and the postoperative data value is(194.70±23.33)mm3.The difference has statistical significance(t=6.13,P<0.001).The preoperative data value of ACA is(41.19±4.40)°,and the postoperative data value is(41.32±3.45)°.The difference has no statistical significance(t=-0.34,P>0.5).The preoperative data value of NCT is(14.81±4.89)mmHg, and the postoperative data value is(9.99±2.03)mmHg.The difference has statistical significance(t=18.59,P<0.001).2.Analysis of the relationship between the parameters of anterior segment of 342 eyes and the data value of NCT as follows:The preoperative data value of CCT has positive correlation with the preoperative data value of NCT,The postoperative data value of CCT has positive correlation with the postoperative data value of NCT( r1=0.294,P<0.001;r2=0.496,P<0.001),The minus value of preoperative and postoperative of CCT has positive correlation with the minus value of preoperative and postoperative of NCT(r=0.20,P<0.001);The preoperative data value of SCC has no correlation with the preoperative data value of NCT(r=0.03,P>0.05),the postoperative data value of SCC has positive correlation with the preoperative data value of NCT(r=0.20,P<0.001),The minus data value of preoperative and postoperative of SCC has positive correlation with the minus data value of preoperative and postoperative of NCT(r=0.23,P<0.001);The preoperative and the postoperative data value of ACV has no correlation with the preoperative and the postoperative data value of NCT separately( r1=0.11,P>0.05;r2=-0.11,P>0.05),The minus data value of preoperative and postoperative of ACV has positive correlation with the minus data value of preoperative and postoperative of NCT(r=0.35,P<0.05);The preoperative and the postoperative data value of ACD has no correlation with the preoperative and the postoperative data value of NCT separately( r1=0.03,P>0.05;r2=0.03,P >0.05),The minus data value of preoperative and postoperative of ACD has no correlation with the minus data value of preoperative and postoperative of NCT(r=0.04,P>0.5). Conclusion :1.The data value of NCT reduce statistically significant 1week after SBK surgery,and the intraocular pressure reduce too.2.The data value of CCT、SCC and e-value reduce statistically significant 1week after SBK surgery,the data value of Q increase statistically significant 1week after SBK,but the data value of PCC has no statistical significant change 1week after SBK surgery.3.The data value of ACD、ACV reduce statistically significant 1week after SBK surgery, but the data value of ACS has no statistical significant change 1week after SBK surgery.4.The minus data value of CCT、SCC、ACV before and after SBK surgery have positive correlation with the minus data value of NCT before and after SBK surgery separately.It means,the data value of CCT reduce may cause the data value of NCT reduce; the data value of SCC reduce may cause the data value of NCT reduce;the data value of ACV reduce may cause the data value of NCT reduce.5.Because of the changes of data value of CCT、SCC and ACV,the data value of NCT decreases 1week after SBK surgery.It is incorrectly to rectify the postoperative intraocular pressure only through the independent variable of corneal parameters.6.The changes of CCT and SCC have impact upon the way we measure the IOP through non-contact tonometer.The definite result of IOP needs to be studied further by DCT,which have no error affected by corneal factors as CCT and SCC.