| As the development of the excimer laser instrument and the improvement of the operation, with its advantages of good efficacy、predictability,and safety, LASIK has gained wide acceptance among doctors and patients. However, in addition to the improvement of the naked eye eyesight, people are in the pursuit of better visual quality further. But the surgery increase high-order aberration inevitably as a result of lowering the retinal imaging, some patients postoperative visual quality decline with physical symptoms of night vision decline,halo,glare. Traditional corneal refractive surgery can just correct the low-order aberrations,but it can not correct eye high-order aberrations and it also increases new aberrations. To improve visual quality of these patients, there are corneal refractive surgery for different individuals, namely individul excimer. It includes aberration-free excimer laser aberration, corneal wavefront-guided excimer laser aberration and corneal topography guided excimer laser aberration and Q value guided excimer laser aberration,these customized patterns are in order to reduce postoperative high-order aberrations. Aberration-free LASIK is based on aberration elimination program,the target is correcting the low order aberrations(spherical equivalent and cylindrical equivalent) at the same time,with less inducing of additional new higher-order aberrations, to keep the corneal’s asphericity and recover postoperative visual acuity faster. At present domestic report about this model of invidual excimer are rare. This study is to analysis the preoperative and postoperative corneal aberration through the application of aberration elimination program,and to discuss the effect for myopia or myopic astigmatism and changes of postoperative high-order aberrations,total higher-order aberrations. MethodsChoose 76 eyes(76 cases) undergoing aberration-free LASIK of myopia and myopic astigmatism between December 2013 and August 2014 in our hospital excimer laser room.All 76 patients’ right eyes were selected as the research object, male 44 eyes(44 cases), the female 32 eyes(32 cases).Aged 18~38, average(22.80±4.50).Patients preoperative are tested by preoperative computer optometry, main optometry, comprehensive optometry, Orbscan Ⅱcorneal topography, intraocular pressure, corneal wavefront aberration Optikon 2000 analyzer examination.Using Wavelight FS 200 femtosecond laser, Amaris 500 s excimer laser machine for excimer laser. Recording aberration values of preoperative and postoperative, including total root mean square value of Coma, Spab and total higher-order aberrations by Optikon 2000 corneal wavefront aberration analyze. Statistical analysisSPSS 17.0 statistical software for data statistics analysis, using independent sample t-test, as well as inspection level alpha 0.05, with P < 0.05 difference was statistically significant. Results 1 postoperative three months naked eyesight and residual diopterAfter three months,76 eyes all meet best corrected vision.Preoperative and postoperative naked eye vision acuity are all over 0.8, 11 eyes(14.47%) of the naked eye eyesight below 1.0;33 eyes(43.42%) of the naked visual acuity are over 1.0,but VII less than 1.2; 32 eyes(42.11%) of the naked eye eyesight are 1.2 or above.All 76 eye diopter residual within ±1.00 D postoperative three months, the average residual diopter was(0.14±0.56) D, 63 eyes(83.30%) of the residual diopter within ±0.50 D. 2 Preoperative and postoperative three months the comparison of comatic aberration, spherical aberration, total higher-order aberration RMS value.After three months, 76 eyes’ coma, spherical aberration and total higher-order aberration of root mean square value are compared with preoperative, it showed a trend of increase over all, but there was no statistically significant difference.Coma. preoperatively,coma,spherical aberration and total higher-order aberrations were(0.116 ±0.053)μm,(0.050 ±0.025)μm,(0.050 ±0.058)μm;After 3 months, on average, coma, spherical aberration and total higher-order aberrations were(0.161 ±0.097)μm,(0.075 ±0.039)μm,(0.075 ±0.182)μm. postoperative 3 months,coma, spherical aberration and total higher-order aberrations, respectively, compared with preoperative, there was no statistically significant difference(t = 1.508, P = 0.080; t = 1.999, P = 0.053; t = 1.435, P = 0.075).26 eyes(34.21%)of the postoperative coma delined, 50 eyes(65.79%) of the postoperative coma increased;21 eyes(27.63%)of the postoperative spherical aberration is reduced, 55 eyes(72.37%) of the postoperative spherical aberration increased;24 eyes(31.58%), postoperative total higher-order aberration is reduced, 52 eyes(68.42%), postoperative total higher-order aberrations increased. 3 Corneal aberration changes relationship with preoperative spherical equivalent(1) According to the preoperative spherical equivalent, compare the preoperative and postoperative corneal aberration:moderate myopia: preoperative and postoperative three months coma(0.110±0.046,0.133±0.079)μm, the spherical aberration(0.047±0.059, 0.059±0.037) μmand total higher-order aberrations(0.161±0.047,0.211±0.156)μm,respectively, there was no statistically significant difference(t = 1.530, P = 0.120; t = 1.774, P = 0.080, t = 2.053, P = 0.052).Highly myopia: preoperative and postoperative three months coma(0.122± 0.060,0.188±0.105)μm, the spherical aberration(0.053±0.025, 0.090±0.035) μm and total higher-order aberrations(0.169±0.067,0.265±0.201)μm were compared, the difference was statistically significant(t = 3.408, P = 0.005; t = 5.372, P = 0.0001, t = 2.829, P = 0.005).(2) Moderate group all kinds of corneal aberration changesModerate group coma, spherical aberration, total higher-order aberrations average variation were(0.023 ±0.091)μm,(0.011 ±0.042)μm,( 0.011 ±0.157)μm.Postoperative three months coma compared with preoperative 15 eyes(40.54%) reduced, which is 0.56 times lower, the increase of coma has 22 eyes(59.46%), the average increase is 0.74 times; compared with preoperative.postoperative three months spherical aberration 15 eyes(40.54%) decreased, which was 0.44 times lower, the spherical aberration increase with 22 eyes(59.46%), the average increase 0.69 times.Postoperative three months total higher-order aberrations 14 eyes(37.84%) reduced, which was 0.30 times lower, total higher-order aberrations 23 eyes(62.16%) increased, the average increase by 0.68 times.(3) Height groups of all kinds of corneal aberration changesAfter three months, height groups coma, spherical aberration, total higher-order aberrations average and variation were(0.066 ±0.119)μm,( 0.037 ±0.041)μm,( 0.037 ±0.207)μm.Postoperative three months coma compared with preoperative 11 eyes(28.21%) reduced, which is 0.52 times lower, the increase of coma has 28 eyes(71.79%), the average increased 0.92 times,Compared with preoperative.Postoperative three months 6 eyes(15.38%) spherical aberration decreased, which is 0.42 times lower, the spherical aberration increase with 33 eyes(84.62%), the average increase by 0.89 times.Postoperative three months total higher-order aberrations compared with preoperative 10 eyes(25.64%) reduced, which is 0.22 times lower, total higher-order aberrations increased 29 eyes(74.36%), the average increase by 0.84 times. ConclusionAberration-free LASIK treatment can effectively reduce the increase of higher-order aberrations for myopia and myopic astigmatism, especially in moderate myopia and myopic astigmatism. |
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