Sub-Bowman keratomileusis versus femtosecond laser in situ keratomileusis on the long-term visual recovery: A comparative study

Purpose: To explore the long?term visual quality of the same subjects after sub?Bowman keratomileusis (SBK) or femtosecond laser in situ keratomileusis (FS?LASIK). Methods: This prospective study included patients screened for corneal refractive surgery at the Refractive Surgery Center of our Hospital between November 2017 and March 2018. One eye underwent SBK, while the other eye underwent FS?LASIK. Total higher?order aberrations, coma aberrations, and clover aberrations were evaluated before and at 1 month and 3 years after the procedure. The visual satisfaction of both eyes was investigated, respectively. The participants completed a surgical satisfaction questionnaire. Results: Thirty?three patients were included. There were no significant differences in total higher?order aberrations, coma aberrations, and clover aberrations between the two procedures before and 1 month and 3 years after surgery (all P > 0.05), except for the total coma aberrations in FS?LASIK were significantly higher compared with the SBK group at 1 month after surgery [0.51 (0.18, 0.93) vs. 0.77 (0.40, 1.22), P = 0.019]. The surgical satisfaction questionnaire scores of the SBK group and the FS?LASIK group were 9.8 ± 0.8 and 9.8 ± 0.8, respectively, at 1 month, and 9.7 ± 0.9 and 9.7 ± 1.0, respectively, at 3 years (all P > 0.05). Conclusion: There were no differences in corneal aberrations and satisfaction between SBK and FS?LASIK procedures at 1 month and 3 years.

Changes of angle Kappa and corneal morphology changes in myopic patients after Sub / 中南大学学报(医学版)

OBJECTIVES@#To investigate angle Kappa and diopter distribution in myopic patients and the changes of angle Kappa and corneal morphology after Sub-Bowman-Keratomileusis (SBK), and to analyze the effects of the surgery on corneal morphologic changes and the patients' near fixation characteristics.@*METHODS@#The clinical data of 134 myopic patients (268 eyes) undergoing SBK from August 2015 to August 2016 were retrospectively analyzed. Angle Kappa, corneal curvature in the central corneal region of 3 mm, and post-corneal Diff value were measured by Orbscan IIz Corneal Topography System before operation, 1 month and 6 months after operation. According to the values of angle Kappa before SBK, the patients were divided into 2 groups: the large K group (angle Kappa≥5°, 71 eyes) and the small K group (angle Kappa<5°, 197 eyes). Correlation analysis of the factors influencing angle Kappa at 6 months after operation was performed.@*RESULTS@#In the large K group, angle Kappa was (5.67±0.65)°, spherical equivalent was (-4.84±2.32) D, and angle Kappa was decreased after operation (both @*CONCLUSIONS@#The angle Kappa is decreased in low-moderate myopia patients with large angle Kappa, while is increased in high myopia patients with small angle Kappa after SBK. Myopia patients after SBK will look for the new balance of the binocular accommodation and vergence function for improving the comfort in the near-work situations.

Changes of anterior segment structure after sub-bowman keratomileusis / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To observe the effect of sub-bowman keratomileusis(SBK)on the posterior corneal curvature, posterior corneal elevation and anterior chamber parameters.<p>METHODS: Prospective self controlled study. Totally 49 patients(97 eyes)with myopia who had planned for SBK were included in this study, mean posterior corneal curvature, central posterior corneal elevation(PCE), anterior chamber volume(ACV), central and peripheral anterior chamber depth(ACD)were measured by Oculyzer before and 1wk, 1y, 3y after surgery. Repeated measure analysis of variance was adopted for data analysis.<p>RESULTS: There were no significant differences in mean posterior corneal curvature at any time point postoperatively compared with that preoperatively(<i>P</i>>0.05). However, central PCE, ACV and central ACD at 1wk, 1y and 3y postoperatively were all decreased(<i>P</i><0.01). Except for the anterior peripheral ACD at 3y after SBK, other peripheral ACD at any time point postoperatively were all decreased(<i>P</i><0.05).<p>CONCLUSION: The posterior corneal curvature remained stable after SBK, while the central PCE shifted slightly backward and the entire anterior chamber became shallow.

Early changes in posterior corneal elevation and related factors after femtosecond laser assisted LASIK and SBK / 中华实验眼科杂志

Objective To compare the early change of posterior corneal elevation with femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) and sub-Bowman keratomileusis (SBK) by Oculyzer and analyze the related factors after FS-LASIK.Methods A longitudinal observational study was designed.Ninety-one eyes of 46 patients with myopia or myopic astigmatism in the First Affiliated Hospital of Anhui Medical University from January to April in 2016 were divided into FS-LASIK group (53 eyes of 27 patients),SBK group (38 eyes of 19 patients)according to the patients' wishes and each part of corneal elevation change values were explored after FS-LASIK and SBK surgeries.The posterior corneal elevation was measured at twenty-seven measuring points along the central,paracentral,midperipheral and peripheral zone (vertex and 1,2 and 3 mm radius) using Oculyzer preoperatively,l day,7 days and 1 month postoperatively,respectively.Written informed consent was obtained from each patient before the surgery.Results In the FS-LASIK group,the posterior corneal elevation difference values in the central zone were (-0.924± 1.859),(-1.151 ± 1.586) and (-0.940 ± 1.994) μm 1 day,7 days and 1 month postoperatively,respectively.In the periphery zone,the elevation difference values were (1.046 ± 1.667),(1.172 ± 1.566) and (1.023±1.622)μm.In the paracentral and midperipheral zone,the cornea displayed slightly backward or forward shift.In SBK group,the posterior corneal elevation difference values of the ve,ex were (-0.684 ± 1.454),(-1.053 ±1.723) and (-0.553 ± 1.572) μm 1 day,7 days and 1 month after operation,respectively.In the paracentral and midperipheral zone displayed the same trend with FS-LASIK group,and in the periphery,the values were (1.207 ±1.317),(1.327 ± 1.529) and (1.208 ± 1.415) μm.There were no statistically significant differences in posterior corneal elevation between the two surgery modes among the three time points (all at P ＞ O.05).At 1 month postoperatively,only two independent variables,which were spherical equivalent (SE) and ablation depth (AD)entered the regression in the central and paracentral zones.Independent variables,such as central thinnest corneal thickness (TCT),SE,AD,residual bed thickness (RBT) and the ratio of AD and TCT (AD/TCT) did not enter the regression in other two areas.Conclusions The posterior corneal elevation in the central 6 mm area shows tiny change in the early stage and the variation is larger 7 days after operation in the two groups,but it does not result in keratectasia.With the increase of SE and AD,the posterior corneal elevation is more likely to be affected.

Study of postoperative visual quality and dry eye and biomechanical stability of patients with myopia and astigmatism treated with different corneal refractive surgeries / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the visual quality, dry eye and biomechanical stability of patients with myopia and astigmatism after different corneal refractive surgeries. ·METHODS: A total of 986 patients with myopia and astigmatism were selected as the research object in our hospital from July 2015 to July 2016, according to the operation mode of the selection of the research object, the 986 patients were randomly divided into small incision lenticule extraction ( SMILE) group, femtosecond laser in situ keratomileusis ( FS-LASIK ) group, sub-bowman-keratomileusis ( SBK ) group and laser-assisted in situ keratomileusis ( LASIK ) group. The postoperative visual quality was determined by comparing the diopter, uncorrected visual acuity ( UCVA ) , best corrected visual acuity ( BCVA) and high-order image difference of 25d, 90d. The postoperative dry eye condition was determined by comparing the postoperative tear secretion test ( Schirmer Ⅰ test ) , tear film rupture time ( BUT ) and fluorescence staining ( FS) . The biomechanical stability of the patients was determined by comparing the corneal hysteresis ( CH ) and corneal resistance factor ( CRF ) values of the four groups. ·RESULTS: The diopter, UCVA, BCVA and high-order aberration comparison of FS-LASIK group, SBK group and LASIK group between before and after surgery, showed no significant difference ( P>0. 05 ); on diopter, BCVA, UCVA, there was no significant difference between before and after surgery in SMILE group (P>0. 05), but statistical significance difference on high order aberration (P<0. 05). The BUT and FS value of the four groups decreased obviously after operation, and the difference was statistically significant (P<0. 05). In LASIK group SIt after operation significantly decreased, with statistically significant compared with that before operation ( P <0. 05). After operation, CH and CRF of the four groups decreased with significant differences (P<0. 05). ·CONCLUSION: SMILE, FS-LASIK, SBK and LASIK are equally safe, effective and stable in the treatment of myopia and astigmatism.

Comparative study of iris location guided SBK and thin-flap LASlK for extremely high myopia / 国际眼科杂志(Guoji Yanke Zazhi)

?AlM:To compare the effect of iris location guided sub-bowman keratomileusis ( SBK ) and iris location guided thin - flap laser in situ keratomileusis ( LASlK ) for extremely high myopia treatment. ?METHODS:lris location guided SBK was performed in 64 eyes of 32 patients with extremely high myopia and 42 eyes of 84 patients were received iris location guided thin-flap LASlK. All the patients’ spherical refraction was-9. 00D ~ - 11. 00D and the age was 22 ~ 35 years. Uncorrected visual acuity ( UCVA) , refraction, split-lamp examination, topography examination, central corneal stroma thickness, thickness of central corneal flap, thickness of peripheral corneal flap and complication was examined in these patients and follow-up was 6mo. ?RESULTS:At 6mo after surgery, 93. 8% of the patients received iris location guided SBK and 92. 9% received iris location guided thin-flap LASlK achieved a UCVA better than 20/20. There was no significant difference between two groups. Refraction between ±0. 5D was 89. 1% of SBK group and 84. 5% of LASlK group. There was no significant difference. Corneal rear surface height of SBK was 0. 046±0. 012μm and LASlK was 0. 056±0. 015μm. Thickness of corneal stroma after surgery was 328. 6±14. 7μm in SBK group, while it was 301. 2±21. 6μm in LASlK group and there was significant difference ( t =3. 127, P=0. 001). BUT was 11. 38±4. 02s and 17. 81±4. 89s in SBK and LASlK group respectively, with no statistical difference. There was no serious complication in two groups.?CONCLUTlON:Both iris location guided SBK and thin-flap LASlK are effective for extremely high myopia, but SBK is safer and more predictive than thin-flap LASlK.

Influence of topical Iotemax on intraocular pressure following excimer laser corneal refractive surgery / 中华实验眼科杂志

Background Excimer laser corneal refractive surgery is widely used because it reduces the dependency of refractive error eye to glasses.However,the adverse effects of anti-inflammatory drugs is a problem after operation.Lotemax eyedrops is a kind of steroidal anti-inflammatory drug,with a good effect on the operative eye.But its influence on intraocular pressure(IOP) after long-term topical administration is less studied.Objective This study was to investigate the influence of lotemax eyedrops on IOP after long-term topical administration in myopic eyes received excimer laser corneal refractive surgery.Methods An one-month retrospective case serial study was adopted.The case history data of 1552 eyes from 1552 Patients who received excimer laser corneal refractive surgery were collected in Tangshan Eye Hospital from 2011 January to 2012 January,including 321 eyes with laser in situ keratomileusis(LASIK),608 eyes with sub-Bowman keratomileusis (SBK) and 623 eyes with femtosecond laser for flap excimer laser in situ keratomileusis(FS-LASIK).Lotemax eyedrops was topically administered after operation 4 times per day initial and then decreased 1 time weekly for 1 month.IOP was measured in before,1 week,2 weeks,3 weeks,4 weeks after operation with non-contact tonometer.The increasing range of IOP was divided into ＜5 mmHg,5-15 mmHg and ＞ 15 mmHg after operation.Optical head parameters were measured by Heidelberg retina tomography when IOP increasing after operation.Results Within 1 month,elevated IOP was found in 47 of 1552 eyes after administration of lotemax eyedrops,including 3.12％ (10/321) in the LASIK group,3.29％ (20/608) in the SBK group and 2.73％ (17/623) in the FS-LASIK group,without significant difference among them(x2 =1.95,P＞0.05).The IOP elevated 1 week after operation and remained normal after that till drug withdrawal in all eyes.There were no significant differences in the disk area (1.65 ±0.44) mm2 vs.(1.66 ±0.44) mm2,disk volume (0.40 ±0.09)mm3 vs.(0.39±0.08) mm3 and mean nerve fiber layer thickness (0.28 ± 0.08) mm vs.(0.29 ± 0.07) mm in IOP elevation duration compared with 1 month after IOP recovery(t =0.34,0.81,0.48,P＞0.05).Conclusions Topical administration of 0.5％ lotemax eyedrops after excimer laser corneal refractive surgery leads to reversible high IOP.It is very important to monitor the IOP during use of the drug.