Analysis Of Changes Of Kappa Angle In Patient With Myopia Of Different Position And Effect Of Adjusted Kappa Angle Of Individual Laser Assisted In-situ Keratomi Leusis On High Level Aberration

Objective: To investigate the change of Kappa angle in patient withmyopia of sitting and supine position during laser assisted in-situ keratomi leusis(LASIK). Method: A total of215patients with myopic included395eyes whounderwent LASIK were divided into low, middle and high myopia groups according todifferent diopters. The horizontal and vertical offsets of kappa angle in sitting positionof preoperative analytical system examination were measured by Oculus Pentacam.During the operation the X and Y axis tracking modulation of ALLEGRETTOWavelight Excimer Laster System were opened for getting horizontal and verticaloffsets of kappa angle in supine position. All data were analyzed respectively. Results:1Kappa angle of223eyes (56.4%) were positive values in sitting position, and343eyes(86.8%) were positive values in supine position.2.The relationship between kappaangle and diopter was analyzed with one-factor analysis of variance.The differences ofhorizontal offsets of kappa angle in different position of1three groups were nostatistically significant (P＞0.05),but the differences of vertical offsets of kappa angleof the three groups were statistically significant (P＜0.05).3.There were significantdifferences in horizontal and vertical kappa angle between sitting and supine position bypaired T test (P＜0.05), and there were positive correlations.4. The offsets of kappaangle in sitting and supine positions had a significantly negative relation with the degreeof myopia (sitting position R=-0.109，supine position R=-0.172; P＜0.05). Conclsions:There was correlation in horizontal and vertical offsets of kappa angle in sitting andsupine positions. With the increase of the myopic degree vertical offset of kappa angleis increased.Clinicians should take into account different postures when refractivesurgery need be performed. Objective To explore the effect of adjusted kappa angle of laser assistedin-situ keratomi leusis (LASIK)on high level r aberration in treatment ofmyopia.Methods: A total of308patients(538eyes) with myopic who underwentLASIK in our hospital from2011July to December were divided into observationgroup and control group according to operative methods. A total198patients (350eyes)in observation group underwent adjusted angle kappa of LASIK,while109patients(188eyes)in control group took traditional LASIK.The vision restoration in twogroups were observed.Results Values of postoperative root mean squarevalue(RMSh),spherical aberration（Z40）and Z3-1in observation group and values ofpostoperative RMSh, Z40, Z31andZ3-1showed significant differences,compared withthose before operation in the two groups(P <0.05);there were significant differences inpostoperative values of Z40, Z31in the two groups Between pre-surgery and1mo aftersurgery in two groups(P <0.05).The differences in postoperative aberration of increasevalues of RMSh and Z40in patients with different levels myopia in the two groups werestatistically significant (P <0.05);there was significant differences in postoperativeincreased value of aberration Z3-1in observation group (P <0.05); there was significantdifferences of postoperative increased values in Z33、Z31in patients with low myopia,Z31andZ3-1in patients with medium myopia and Z31in patients with severe myopia inobservation group,compared with those in control group(P <0.05). Conclusion: Adjustekappa angle of LASIK can cut down postoperative level of comatic aberration andimprove postoperative visual quality.