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AIM:To evaluate corrective effect and stability of corneal morphology in patients with moderate to high myopia after 2a treatment of femtosecond laser assisted laser in situ keratomileusis(FS-LASIK)Xtra.METHODS:Retrospective case-control study. A total of 30 cases(58 eyes)Patients with moderate to high myopia combined with astigmatism who planned to undergo refractive surgery in our hospital from August 2019 to August 2020 were included, and different types of surgery were performed respectively based on the relevant index of keratoconus screening in the preoperative corneal topography. They were divided into FS-LASIK group and Xtra group, with 15 cases(29 eyes)in each group. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE)and the corneal curvature of the anterior and posterior surfaces of different diameters(3, 5 and 7 mm)measured by Sirius three-dimensional corneal topography were observed preoperatively and 3 mo, 1 and 2 a postoperatively.RESULTS: The UCVA of the two groups of patients at different time points after surgery was significantly increased compared with preoperatively(both P<0.01), and there was no difference in UCVA and SE between the two groups(P>0.05). After 2 a postoperatively, residual astigmatism was -0.25-0 D in 25 eyes(86%)of the FS-LASIK Xtra group and 24 eyes(83%)of the FS-LASIK group. The actual corrected SE and expected corrected SE of both groups were positively correlated(both P<0.05). There were differences in corneal curvature on the surface of different diameter areas(3, 5, and 7 mm)between the two groups at 3 mo, 1, and 2 a postoperatively compared with preoperatively. After 1 and 2 a postoperatively, the corneal posterior surface curvature of the FS-LASIK Xtra group with corneal diameter of 3 and 5 mm was higher than that of the FS-LASIK group(P<0.05).CONCLUSIONS:FS-LASIK Xtra has good safety, efficacy and predictability in correcting patients with moderate to high myopia.
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Purpose: To compare the visual outcomes in patients undergoing small?incision lenticule extraction (SMILE) for correction of myopic astigmatism (??1.50 D) with or without manual cyclotorsion compensation. Methods: A prospective, double?blinded, randomized, contralateral study was conducted in the refractive services of a tertiary eye care center. Eligible patients with bilateral high myopic astigmatism (?1.5 D) and intraoperative cyclotorsion (?5°) undergoing SMILE between June 2018 and May 2019 were included. Cyclotorsion compensation was performed using triple centration method before femtosecond laser delivery. Uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) measurement, manifest refraction, slit?lamp biomicroscopy, and corneal tomography were performed preoperatively and at 1 and 3 months’ postoperative visit. Astigmatic outcomes were analyzed using Alpins criteria. Results: A total of 30 patients (60 eyes) were included in this study. The patients underwent bilateral SMILE surgery, with manual cyclotorsion compensation in one eye (CC group, n = 30 eyes) and no cyclotorsion compensation in the other eye (NCC group, n = 30 eyes). Preoperative astigmatism and intraoperative cyclotorsion were ?2.0 D and 7.03° ± 1.06° (CC) and ?1.75 D and 7.24° ± 0.98° (NCC) (P = 0.472 and 0.240, respectively). No significant differences were noted in mean refractive spherical equivalent (MRSE), UDVA, CDVA, and refractive error between the two groups at 3 months’ postoperative visit. Astigmatic outcomes measured using Alpins criteria demonstrated no significant difference between the two cohorts. Conclusion: The cyclotorsion compensation technique provided no additional advantage in terms of astigmatic outcomes or postoperative visual quality, in eyes with high preoperative astigmatism and intraoperative cyclotorsion.
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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.
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Objective:To compare the changes in functional optical zone (FOZ) and corneal morphology in myopes between femtosecond small incision laser lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK).Methods:A cohort study was performed.A total of 94 patients (94 eyes) who underwent FS-LASIK or SMILE at Eye Hospital, Wenzhou Medical University from March to December 2021 were enrolled.The selected patients were divided into a SMILE group (46 cases, 46 eyes) and an FS-LASIK group (48 cases, 48 eyes) according to the surgical procedure, and the follow-up period was 6 months.The primary outcome measures were postoperative changes in corneal FOZ and Q-value, and the secondary outcome measures were changes in central corneal thickness (CCT) and mean corneal curvature (Km). Corneal Q-value, horizontal and vertical FOZ diameters, CCT, and Km were recorded before surgery and at 1 day, 1 week, 1 month, and 6 months after surgery using the Pentacam anterior segment analysis system, and the differences in each parameter and the trends of changes between the two groups were compared.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Eye Hospital, Wenzhou Medical University (No.2021-034-k-27). Written informed consent was obtained from each subject.Results:There were statistically significant overall differences in the postoperative horizontal and vertical FOZ diameters between the two groups (horizontal diameter: Fgroup=7.06, P<0.001; Ftime=64.18, P=0.001; vertical diameter: Fgroup=11.08, P<0.001; Ftime=77.14, P<0.001). The horizontal and vertical FOZ diameters were significantly larger in SMILE group than in FS-LASIK group at various postoperative time points, and the differences were statistically significant (all at P<0.001). In the two groups, the postoperative 1-week, 1-month and 6-month horizontal FOZ diameters and the postoperative 1-week and 1-month vertical FOZ diameters were smaller than the postoperative 1-day ones, and the differences were statistically significant (all at P<0.05). There were significant overall differences in Q-values at different postoperative time points between the two groups ( Fgrouup=53.11, P=0.019; Ftime=29.18, P<0.001). The postoperative 1-day, 1-week, and 1-month Q-values of FS-LASIK group were significantly higher than those of SMILE group (all at P<0.05). The postoperative 1-week Q-value was significantly larger than the postoperative 1-day value in SMILE group ( P<0.001). The postoperative Q-values gradually decreased with time in FS-LASIK group, with significant pairwise differences at all adjacent time points (all at P<0.001). There were significant differences in CCT at various postoperative time points between the two groups ( Ftime=21.43, P<0.01). In FS-LASIK group, the CCT was decreased at 1 week than 1 day after surgery and was increased at 6 months than 1 week after surgery, and the differences were statistically significant (all at P<0.05). In SMILE group, the postoperative 1-week, 1-month and 6-month CCT was increased in comparison with the postoperative 1-day value, and the differences were statistically significant (all at P<0.05). There was no significant overall difference in the Km between the two groups ( Fgroup=27.29, P=0.41). There were significant pairwise differences in the Km at different postoperative time points between the two groups (all at P<0.001). The postoperative 6-month Km was smaller than the postoperative 1-day value in SMILE group, and the postoperative 6-month Km was greater than the postoperative 1-day value in FS-LASIK group (both at P<0.05). Conclusions:The FOZ shows a trend of gradual reduction within a month after SMILE and FS-LASIK.The FOZ is larger after SMILE than after FS-LASIK.The morphologic stability of corneal FOZ is better after SMILE than after FS-LASIK.
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Objective:To investigate the status of corneal epithelial remodeling and changes in corneal aberration after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and FS-LASIK combined with corneal collagen cross-linking (FS-LASIK Xtra), and to analyze the relationship between corneal epithelial thickness (CET) and corneal aberration.Methods:A cohort study was conducted.A total of 172 patients (172 eyes) who underwent FS-LASIK at Yinhai Eye Hospital of Chengdu University of Traditional Chinese Medicine were enrolled from June 2021 to February 2022.The 172 eyes were divided into FS-LASIK group (94 eyes) and FS-LASIK Xtra group (78 eyes) according to the surgical procedure, with a total follow-up of 6 months.The cornea was divided into a central 2-mm ring and a ring of 2-5 mm centered on the central cornea.CET at 9 regions in the central 0-5 mm area was measured by OCT before and at 1, 3 and 6 months after surgery, and the corneal higher-order aberration (HOA) was measured by the iTrace visual function analyzer.The main outcomes were the increase in CET (ΔCET), and corneal HOA at 6 months after surgery.The relationship between central corneal ΔCET and corneal aberration was analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Yinhai Eye Hospital of Chengdu University of Traditional Chinese Medicine (No.2021yh-009). Written informed consent was obtained from each subject.Results:At 1, 3 and 6 months after surgery, the central, superior, superior nasal, nasal, inferior nasal, inferior, inferior temporal, temporal and superior temporal ΔCET were significantly smaller in FS-LASIK Xtra group than in FS-LASIK group (all at P<0.05). In FS-LASIK Xtra group, 6-month postoperative central, superior, superior nasal, inferior and inferior temporal ΔCET were significantly larger than those at 1 month after surgery, and 3- and 6-month postoperative temporal ΔCET were significantly larger than that at 1 month after surgery, and 6-month postoperative superior temporal ΔCET was significantly larger than those at 1 and 3 months after surgery (all at P<0.05). In FS-LASIK group, 3- and 6-month postoperative central, superior, inferior and inferior temporal ΔCET were significantly larger than those at 1 month after surgery, and 6-month postoperative superior nasal ΔCET was significantly larger than that at 3 months after surgery, and 6-month postoperative nasal, inferior nasal, temporal, superior temporal ΔCET were significantly larger than those at 1 and 3 months after surgery (all at P<0.05). There was no significant difference in vertical trefoil, vertical and horizontal coma changes at different time points after surgery between both groups (vertical trefoil: χ2group=4.27, P=0.118; χ2time=0.01, P>0.05.vertical coma: χ2group=5.74, P=0.057; χ2time=0.08, P=0.957.horizontal coma: χ2group=3.97, P=0.137; χ2time=0.51, P=0.773). The tilted trefoil changes at 1, 3 and 6 months after surgery of FS-LASIK Xtra group were significantly larger than those of FS-LASIK group (all at P<0.05). The 6-month spherical aberration change in FS-LASIK Xtra group was significantly higher than that at 1 month after surgery, and the 6-month spherical aberration change in FS-LASIK group was significantly higher than that at 1 and 3 months after surgery (all at P<0.05). The 6-month total HOA change in FS-LASIK group was significantly lower than that at 1 and 3 months after surgery (all at P<0.05). In FS-LASIK group, central corneal ΔCET was weakly positively correlated with spherical aberration at 1 and 6 months after surgery ( rs=0.257, P=0.008; rs=0.244, P=0.012), and was weakly positively correlated with total HOA ( rs=0.253, P=0.009; rs=0.279, P=0.004). Conclusions:The postoperative ΔCET after FS-LASIK Xtra is smaller than that after FS-LASIK, but the homogeneity of ΔCET in each region is similar between the two groups.The changes in corneal HOA after surgery are similar in both groups, and there is a certain association between the overall epithelial distribution and corneal aberration.
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AIM: To investigate the short-term visual quality outcomes after femtosecond laser small incision lenticule extraction(SMILE)and evolution implantable collamer lens(EVO-ICL)implantation for the correction of moderate myopia.METHODS: Prospective control study. A total of 51 cases(51 eyes)with moderate myopia who underwent SMILE or EVO-ICL implantation surgery at Weifang Eye Hospital from April 2021 to February 2022 were selected. They were divided into SMILE group(30 patients, 30 eyes)and EVO-ICL group(21 patients, 21 eyes)according to the surgical methods. The changes of visual acuity [uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA)], diopter [spherical equivalent(SE)] and related parameters of optical quality analysis system(OQAS Ⅱ)were observed before surgery and at 1wk, 1 and 3mo after surgery, and the quality of vision(QoV)questionnaire was completed.RESULTS: At 3mo after surgery, the safety index(postoperative CDVA/preoperative CDVA)of SMILE gruop and EVO-ICL group were 1.20(1.00, 1.20)and 1.20(1.00, 1.38), respectively, the efficacy index(postoperative UDVA/preoperative CDVA)were 1.00(1.00, 1.20)and 1.00(1.00, 1.20), respectively, and the percentage of SE within ±0.50D was 87% and 100%, respectively. In SMILE group, the objective scattering index(OSI)was increased after surgery, while modulation transfer function cutoff frequency(MTF cutoff), contrast visual acuity(VA)100%, and VA20% at 1wk and 1mo after surgery, and Strehl ratio(SR)and VA9% at each time point after surgery were all decreased compared with those before surgery(all P&#x003C;0.05). The OSI, MTF cutoff, SR and VA of EVO-ICL group showed no difference at each time point after surgery compared with those before surgery(all P&#x003E;0.05). The most common visual symptoms after SMILE and EVO-ICL implantation were visual haze and halos, respectively.CONCLUSION: Both SMILE and EVO-ICL implantation have good safety, efficacy and predictability in the short term after the correction of moderate myopia. Both groups had visual symptoms after surgery, but the overall satisfaction of patients was high. Furthermore, EVO-ICL implantation has better objective visual quality performance.
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AIM: To measure the indexes including postoperative distance, middle, near visual acuity and near stereopsis vision of patients with high myopia cataract and corneal astigmatism by femtosecond laser, which can quantify the diameter of capsulorhexis opening, and to evaluate the availability and necessity of Toric intraocular lenses(IOL)in high myopia.METHODS: Prospective case-control study. Patients with binocular high myopia cataract and corneal astigmatism who undergone femtosecond laser-assisted cataract surgery in our hospital were selected, and they were divided into two groups, with 20 cases(40 eyes)in group A(Toric IOL)and 20 cases(40 eyes)in group B(IQ IOL). Indexes, including preoperative corneal astigmatism and spherical equivalent and best-corrected distance visual acuity, uncorrected middle visual acuity, uncorrected near visual acuity, residual refractive astigmatism, near stereopsis acuity, total high-order aberration and total spherical aberration, were measured postoperatively at 7d, 1 and 3mo.RESULTS: The uncorrected middle and near visual acuity, Titmus near stereopsis acuity and residual astigmatism at 7d, 1 and 3mo after surgery were significantly improved in the Toric IOL group than the non-Toric group(all P&#x003C;0.05). The dependence on glasses was reduced. The postoperative best-corrected distance visual acuity, total high-order aberration and total spherical aberration of the two groups showed no statistically significant differences(all P&#x003E;0.05).CONCLUSIONS: The implantation of Toric IOL in patients with high myopia cataract and corneal astigmatism can effectively correct corneal astigmatism, improve postoperative uncorrected middle and near visual acuity and near stereopsis visual function, reduce postoperative dependence on glasses and enhance binocular stereopsis visual function.
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AIM: To evaluate the clinical efficacy of femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation.METHODS:The retrospective study enrolled 22 cases(26 eyes)of cataract patients who underwent femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation from August 2020 to August 2021. Follow-up to 3mo after surgery, the changes of far, intermediate and near visual acuity, aberration, Strehl ratio(SR)and modulation transfer function cutoff(MTF-cutoff)frequency were compared. Defocus curve at 1mo postoperatively was made, and the visual quality and satisfaction were evaluated after 3mo of surgery.RESULTS: The visual acuity of all patients was better than 0.1(LogMAR)at the far, intermediate and near distance at 1d, 1wk, 1 and 3mo postoperatively, and it was significantly improved compared with those before surgery(all P&#x003C;0.01). The defocus curve transitioned smoothly between +0.5 and -3.0D at 1mo after surgery, and visual acuity was better than 0.63. The total aberration and spherical aberration in the whole eye were significantly lower after surgery than before, and the SR and MTF-cutoff were significantly improved at 1d and 1wk after surgery(all P&#x003C;0.05). With high satisfaction and good visual quality, patients could watch at far, intermediate and near distance without wearing glasses at 3mo after surgery.CONCLUSION: Femtosecond laser-assisted cataract surgery combined with PanOptix trifocal intraocular lens implantation gave patients a comfortable and satisfactory full-course vision.
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AIM: To investigate the effect of different preoperative corneal curvature on the size of optical deformation area after femtosecond laser small incision lens extraction(SMILE).METHODS:A prospective study was conducted on 108 consecutive patients who underwent SMILE surgery in our hospital from February 2021 to January 2022. Considering the association between both eyes, only the left eye of each patient was studied. According to the average anterior corneal surface curvature in preoperative, the patients were divided into three groups: Km<42.0D group(n=30), Km>47.0D group(n=26)and conventional corneal curvature group(n=52)with 42.0D≤Km≤47.0D. All patients underwent standardized SMILE surgery, and the laser ablation diameter was 6.5mm. The diameters of optical deformation areas in the three groups were compared at 6mo after operation.RESULTS:There was no significant difference in preoperative data among the three groups except for the mean curvature of the anterior corneal surface(all P>0.05), and there was no significant difference in uncorrected distance visual acuity(UDVA)and subjective refraction at 6mo after operation(all P>0.05). The diameters of the optical deformation zone in the Km<42.0D group, Km>47.0D group and the conventional corneal curvature group were 6.54±0.14, 6.32±0.13, 6.45±0.15mm respectively(F=19.238, P<0.05). The optical area diameter of the group with flat corneal curvature was larger than that of the group with conventional corneal curvature and the group with steeper corneal curvature(P<0.05). The diameter of optical zone in the conventional curvature group was larger than that in the Km>47.0D group(P<0.05).CONCLUSION: When the preset laser cutting diameter is the same, the steeper the corneal curvature before operation, the smaller the diameter of the optical deformation area after operation.
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AIM: To compare the changes in corneal densitometry after small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(FS-LASIK)and investigate the effect of corneal interface haze on vision after SMILE.METHODS: Prospective cohort study. A total of 93 patients(186 eyes)who were scheduled to undergo refractive surgery at the Ophthalmic Refractive Surgery Center of the Affiliated Hospital of Nantong University from May 2020 to October 2021 were included in the study, and there were 48 patients(96 eyes)in the SMILE group and 45 patients(90 eyes)in the FS-LASIK group. The changes in corneal densitometry, spherical equivalent(SE), and uncorrected visual acuity(UCVA)were observed and compared between the two groups before and at 1d, 1wk, 1, 3 and 6mo after surgery.RESULTS: The 93 patients all successfully completed the surgery, and there were no related complications during and after the surgery, and there were no lost cases. The UCVA of FS-LASIK group was 0.044±0.064 and -0.001±0.065 respectively at 1d and 1wk after surgery, which was better than that of SMILE group(0.102±0.077 and 0.023±0.064; all P<0.05). There was no statistical difference in the SE between the two groups at the postoperative follow-ups(P>0.05). The corneal densitometry values at 0-2 and 2-6 mm from corneal vertex and total corneal densitometry at 1d postoperatively in the FS-LASIK group were 18.0(17.5, 18.6), 16.2(15.6, 16.7)and 16.7(16.1, 17.3), which were lower than those of SMILE group [18.6(18.1, 19.3), 16.8(16.4, 17.4), 17.2(16.6, 17.8)](all P<0.05); The corneal densitometry values at 0-2 and 2-6 mm from corneal vertex and total corneal densitometry at 1wk postoperatively in the FS-LASIK group were 17.2(16.7, 17.6), 15.5(15.0, 15.9)and 15.9(15.3, 16.7), which were lower than those of SMILE group [17.6(17.1, 18.3), 16.0(15.6, 16.5), 16.6(15.9, 17.1)](all P<0.05).CONCLUSIONS: The transient interface haze after SMILE is responsible for the early higher corneal densitometry than FS-LASIK. The presence of interface haze is probably a factor for the quality of vision.
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AIM: To investigate the clinical efficacy of femtosecond laser-assisted phacoemulsification combined with goniosynechialysis in the treatment of acute angle-closure glaucoma complicated with cataract.METHODS: A total of 53 patients(60 eyes)with primary acute angle closure glaucoma complicated with cataract admitted to our hospital from April 2020 to February 2021 were selected. They were divided into two groups according to the surgical method, with 28 cases(30 eyes)who were treated with femtosecond laser-assisted phacoemulsification combined with goniosynechialysis in group A, and 25 cases(30 eyes)who were treated with traditional cataract phacoemulsification combined with goniosynechialysis in group B. The effective phacoemulsification time(EPT)and cumulative dissipated energy(CDE)during surgery in two groups were recorded. Patients were followed up to 3mo after surgery, and the intraocular pressure, anterior chamber depth(ACD), best corrected visual acuity, corneal endothelial cell loss rate(ECL)and surgical complications were observed in both groups.RESULTS: The postoperative intraocular pressure was significantly decreased and ACD was significantly increased(all P<0.05), and there was no difference between the two groups(all P>0.05). The postoperative best corrected visual acuity of the two groups was significantly better than that before surgery(P<0.05), and group A was significantly better than group B at 1d after surgery(P<0.05). The EPT, CDE, ECL and incidence of complications(7% vs. 27%)in group A were significantly lower than those in group B(all P<0.05).CONCLUSION: Femtosecond laser-assisted cataract phacoemulsification combined with goniosynechialysis in the treatment of primary acute angle-closure glaucoma combined with cataract has a significant therapeutic effect, which can effectively improve surgical safety, reduce the rate of corneal endothelial cell loss, and have fewer complications.
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AIM: To observe the clinical outcomes of femtosecond laser-assisted cataract phacoemulsification combined with anterior vitrectomy in the treatment of pediatric cataracts.METHODS: Retrospective study. A total of 10 patients(17 eyes)diagnosed as pediatric cataract in Foshan Aier Eye Hospital from January 2021 to September 2022 were collected, including 5 males(9 eyes)and 5 females(8 eyes), with an age of 3～9(4.50±1.20)years old. All children underwent femtosecond laser assisted phacoemulsification combined with anterior vitrectomy. The visual acuity, intraocular pressure and pigment deposits of intraocular lens(IOL)surface, synechia and hyperplasia of posterior capsule lens at 1wk, 1 and 6mo postoperatively were observed during the 6mo follow-up.RESULTS: All surgical procedures were successful, and there was no serious complication intraoperatively or postoperatively. BCVA(LogMAR)was 0.63±0.18 preoperatively and 0.42±0.10, 0.32±0.09, and 0.22±0.08 at 1wk, 1 and 6mo postoperatively(all P<0.001). There was no difference in the comparison of intraocular pressure at different times of surgery(P=0.125). There was no statistically significant difference in the incidence of IOL surface pigment deposits, synechia, and posterior capsule lens hyperplasia at different times after surgery(P>0.05). The incidence of IOL surface pigment deposits at 1wk, 1 and 6mo after surgery was 3 eyes(18%), 1 eye(6%), and 1 eye(6%), respectively, the incidence of synechia was 0 eye, 1 eye(6%), 2 eyes(12%), and the incidence of posterior capsule lens hyperplasia was 0 eye, 0 eye, and 2 eyes(12%), respectively.CONCLUSION: Femtosecond laser-assisted cataract phacoemulsification combined with vitrectomy for the removal of the anterior vitreous can effectively prevent anterior capsular tear and the occurrence of posterior capsule opacification.
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AIM: To observe and compare the changes in retinal peripheral refraction and aberrations after femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)versus small incision lenticule extraction(SMILE)for myopia correction.METHODS: A total of 71 patients(71 eyes)with myopia who underwent FS-LASIK from October 2022 to April 2023 in our hospital were selected as the FS-LASIK group, and 80 patients(80 eyes)with myopia who underwent SMILE were selected as the SMILE group. All patients underwent corneal wavefront aberration measurement and multispectral refractive topography preoperatively and 3mo postoperatively, as well as refraction difference value(RDV)in the range of 0°～10°, 10°～20°, 20°～30°, 30°～40°, and 40°～53° in the annulus of the retina, which were recorded as RDV-(0°～10°), RDV-(10°～20°), RDV-(20°～30°), RDV-(30°～40°), and RDV-(40°～53°). The results of two groups of patients were compared.RESULTS: No significant differences were observed in RDV-(0°～10°), RDV-(10°～20°), RDV-(20°～30°), RDV-(30°～40°), RDV-(40°～53°)between the two groups at 3mo post-operation(all P>0.05). Furthermore, the RDV-(20°～30°), RDV-(30°～40°)and RDV-(40°～53°)of the two groups at 3mo postoperatively were all significantly lower than those preoperatively(all P<0.05). The changes in coma(horizontal)and spherical aberration(SA)at 3mo postoperatively were smaller in the SMILE group [0.106(0.056, 0.171)and 0.115(0.081, 0.182)μm] than in the FS-LASIK group [0.206(0.104, 0.355)and 0.197(0.128, 0.254)μm](Z=-4.170, -5.016, all P<0.05). A negative correlation was found between postoperative SA and postoperative RDV-(10°～53°)(rs=-0.205, -0.181, -0.226, -0.244, all P<0.05).CONCLUSION: Both FS-LASIK and SMILE reduced retinal hyperopic defocus in the peripapillary macular range of 20°～53° eccentricity, and the postoperative changes in coma(horizontal)and SA were smaller with SMILE than with FS-LASIK. There was a certain correlation between postoperative SA and postoperative retinal peripheral defocus.
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Femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)and small incision lenticule extraction(SMILE)are the mainstream corneal refractive surgeries at present. Despite efficacy, safety and predictability they have showed in refractive error correction, there are still complications relating to femtosecond laser, such as suction loss and opaque bubble layer(OBL), due to that the production of corneal flap or lenticule is dependent on the femtosecond laser. OBL is a complication that is unique to femtosecond laser surgery and the bubbles are generated from photo-disruptive effect towards corneal tissues which consisted of water vapor and carbon dioxide, and OBL gradually formed when the bubbles are trapped in the stroma. The bubbles can influence the intraoperative manipulation and postoperative visual quality. This review discusses the mechanism, grading, classification, and influencing factors of OBL and its effects on intraoperative manipulations and postoperative recovery, in the hope of providing reference and basis for further clinical studies.
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AIM:To evaluate the changes in corneal biomechanics of patients with moderate refractive error after receiving small-incision lenticule extraction(SMILE)and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)using the corneal visualization Scheimpflug technology(Corvis ST).METHODS:Prospective cohort study. A total of 65 moderate myopia patients(65 eyes)who were scheduled to undergo refractive surgery at the Ophthalmic Refractive Surgery Center of the Ningxia Eye Hospital from November 2020 to November 2021 were included in the study, and there were 30 eyes in the SMILE group and 35 eyes in the FS-LASIK group. The changes in corneal biomechanical parameters, including integrated radius(IR), inverse concave radius(ICR), deformation amplitude ratio 2mm(DAR2), stiffness parameter at first applanation(SP-A1), ambrosio relational thickness(ARTh)and the central curvature radius at highest concavity(HC-Radius)were observed by Corvis ST between both groups preoperatively and 1 and 3mo postoperatively.RESULTS: There were no statistical significance in biomechanical parameters between two groups of patients 1 and 3mo postoperatively(P&#x003E;0.05). IR, ICR and DAR2 of each groups of patients 1 and 3mo postoperatively were significantly increased than those preoperatively, and SP-A1, ARTh and HC-Radius were significantly decreased than those preoperatively(all P&#x003C;0.05). The biomechanical parameters at 1mo and 3mo postoperatively showed no statistical significance(P&#x003E;0.05). In addition, a positive correlation was found between central corneal thickness(CCT)and ARTh and SP-A1 of the two groups of patients at 3mo postoperatively(FS-LASIK group: r=0.727, 0.819, SMLIE group: r=0.683, 0.434, all P&#x003C;0.05), while a negative correlation was found between CCT and IR and ICR at 3mo postoperatively.(FS-LASIK group: r=-0.697, -0.622, SMLIE group: r=-0.447, -0.491, all P&#x003C;0.05).CONCLUSION:For patients with moderate myopia, both SMILE and FS-LASIK can reduce corneal biomechanical stability. Both surgeries showed no significant differences in the effect on biomechanical, and the biomechanical has been stabilized at 1mo postoperatively. A correlation was found between postoperative CCT and ARTh, SP-A1, IR and ICR.
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Objective:To investigate the risk factors of high intraocular pressure (IOP) after femtosecond laser in situ keratomileusis (FS-LASIK) in patients with high myopia, and construct and verify nomogram model.Methods:A retrospective clinical study. From January 2019 to January 2021, 327 patients (654 eyes) with high myopia treated with FS-LASIK in the Department of Ophthalmology of the 910th Hospital of the People's Liberation Army Coalition Security Force were included in the study. The patients were categorized into high IOP group and non-high IOP group according to whether high IOP occurred after surgery, which were 60 cases and 120 eyes (18.35%, 60/327) and 267 cases and 534 eyes (81.65%, 267/327), respectively. The clinical data of patients in the two groups were analyzed and observed, and the indicators with differences were subjected to one-way and multifactorial logistic regression analyses, and the results of the regression analyses were visualized to obtain the column line graphs using R3.5.3 software, and the accuracy of the column line graphs was verified by the consistency index (C-index), the calibration curves, and the subject's work characteristic curves (ROC curves).Results:Comparison of the number of cases of affected corneal thickness ( χ2=7.424), corneal curvature ( χ2=9.849), glucocorticoid treatment ( χ2=7.222), intraoperative IOP fluctuation ( χ2=11.475), corneal hysteresis ( χ2=6.368), and the incidence of intraoperative complications ( χ2=6.673) in the hypertensive IOP group and the nonvisualized IOP group were statistically significant ( P<0.05). Binary logistic regression analysis showed that corneal thickness >450 μm, corneal curvature≤38 D, glucocorticoid treatment, intraoperative IOP fluctuation, corneal hysteresis ≤8.0 mm Hg (1 mm Hg=0.133 kPa), and intraoperative complications were the risk factors for the occurrence of high IOP after FS-LASIK surgery in patients with high myopia ( P<0.05). The C-index of the column-line graph prediction model based on this was 0.722 (95% confidence interval 0.684-0.760), the calibration curve and the ideal curve were basically the same, and the area under the ROC curve was 0.709. Conclusions:Corneal thickness> 450 μm, keratometric curvature ≤38 D, glucocorticoid treatment, intraoperative fluctuation of intraocular pressure, and corneal hysteresis ≤8.0 mm Hg are the risk factors for the development of hyperopic IOP in highly risk factors for the development of high IOP after FS-LASIK surgery in myopic patients. The column-line diagram model constructed on the basis of the risk factors hava good accuracy.
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Purpose: To compare the clinical outcomes of femtosecond laser–assisted cataract surgery (FLACS) versus conventional phacoemulsification (CP) in terms of refractive outcomes, cumulative dissipated energy, and intraoperative complications. Methods: In this retrospective study performed in a tertiary care ophthalmic hospital, we reviewed 2124 eyes that underwent FLACS or CP. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), cumulative dissipated energy (CDE), and intraoperative complications were analyzed in the study. Results: Out of 2124 eyes, 873 underwent FLACS and 1251 underwent CP. The postoperative mean UCVA after one month was 0.05 ± 0.11 logMAR and 0.14 ± 0.23 logMAR for FLACS and CP, respectively (P < 0.00001). Mean CDVA one month post operation was 0.02 ± 0.07 logMAR and 0.06 ± 0.19 logMAR for FLACS and CP, respectively (P < 0.0001). The CDE for the FLACS group was 6.17 ± 3.86 (P < 0.00001) and it was 9.74 ± 6.02 for the CP group. The intraoperative complication for the FLACS group was 1.60% and the CP group was 2.39% (P < 0.00001). Conclusion: The visual outcomes were better in FLACS compared to CP. The CDE was lower for the FLACS group and FLACS had significantly less intraoperative complications
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We aimed to develop a novel and effective technique for creating a smooth deep lamellar dissection of the cornea using a femtosecond (FS) laser for deep anterior lamellar keratoplasty (DALK), we conducted a retrospective eye bank study. Thirteen fresh human corneas were mounted on an artificial anterior chamber, and deep lamellar cuts were made with a 500?kHz VisuMax FS laser at a level of 50–80 ?m anterior to the Descemet’s membrane (DM). A posterior diameter of 8 mm with a side cut angle of 110° was used for the anterior penetrating side cut. The anterior lamellar tissue was bluntly dissected. The residual posterior stromal beds and side cuts were examined with microscopy and intraoperative optical coherence tomography (OCT) and post?cut endothelial cell evaluations. All corneas revealed a smooth residual posterior stromal bed without any visible irregularities or ridges by microscopy and OCT imaging. Six corneas were suitable for post?cut endothelial cell evaluation 2 days after laser cut, with no significant endothelial cell loss post?laser and blunt dissection of the posterior stroma. FS laser deep lamellar keratoplasty utilizing an ultrafast laser to produce a smooth deep stromal dissection followed by blunt dissection and removal of the anterior stromal tissue yields a consistent and smooth residual stromal bed. The creation of a smooth lamellar dissection in the deep posterior cornea may result in more consistent DALK without the need for air bubble or manual baring of DM that has the risk for DM perforation.
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Anterior lamellar keratoplasty (ALK), of late, has gained popularity because of its prolonged graft survivability as a result of reduced endothelial cell loss. A 56-year-old female with bilateral granular corneal dystrophy was taken up for ALK in the left eye. Because of unforeseen errors during the procedure, the surgeon was obliged to customize a novel technique by using a deep stromal lenticule after removal of Descemet’s membrane. Post-op visual recovery was equivalent to conventional ALK with complete epithelization of the graft. This new or adapted technique has an added advantage for surgeons to prevent forfeiture of the valuable donor tissue. In the developing world, manual dissection is still the primary technique of lamellar keratoplasty and many precious corneas get wasted because of intra-operative unintended errors of dissection and trephination. Therefore, this novel technique holds its importance in saving the precious corneal tissue, especially in developing countries, and opens a new area for exploration.
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We propose a technique for combined femto laser?assisted cataract surgery (FLACS) and limited vitrectomy from the pars?plana site for optimization of surgical results in subluxated cataracts. FLACS creates a free?floating, customised capsulotomy, minimizes stress on compromised zonules, and prechops the nucleus, effectively reducing the ultrasonic power as well as the forces required to chop the nucleus. The area of zonular dehiscence creates a direct communication between the irrigation fluid and the anterior vitreous, leading to its hydration. Trans?limbal vitrectomy creates a continuum between the liquefied vitreous and the main wound, leading to further vitreous loss, and exaggeration of the zonular weakness, while pars?plana vitrectomy avoids this by cutting the liquefied vitreous, near its attachment, thereby preventing further hydration and causing lesser stress to the zonules. A combination of these procedures, along with a capsule support device, gives favorable surgical outcomes in moderate to severe subluxations.