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AIM:To compare the corneal refractive power and visual quality after three kinds of corneal refractive surgery: laser subepithelial keratomileusis(LASEK), transepithelial photorefractive keratectomy(TransPRK)and femtosecond laser assisted in situ keratomileusis(FS-LASIK).METHODS: Retrospective study. A total of 232 patients(464 eyes)who underwent elective corneal refractive surgery in our hospital from January 2021 to December 2022 were selected as the study subjects. They were divided into the LASEK group of 70 cases(140 eyes), TransPRK group of 76 cases(152 eyes), and FS-LASIK group of 86 cases(172 eyes)according to the different surgical choices made by the patients. Uncorrected visual acuity(UCVA), visual quality, biomechanical stability, tear film break-up time(BUT), Schirmer Ⅰ test(SⅠt)and quality of life were compared among the three groups at 1 and 3 mo postoperatively.RESULTS: The UCVA of the three groups significantly improved at 1 and 3 mo postoperatively, the total high-order aberrations, spherical aberration, horizontal coma, and vertical coma of the entire cornea were significantly increased, while the biomechanical stability in all three groups were significantly reduced(all P<0.05). At 3 mo postoperatively, the biomechanical stability in the TransPRK and LASEK groups were higher than those of the FS-LASIK group(all P<0.05), and the TransPRK group had higher quality of life scores than the LASEK group and FS-LASIK group(P<0.05). Furthermore, there was no significant difference in preoperative or postoperative BUT and SⅠt among the three groups(all P>0.05).CONCLUSION:In the treatment of ametropia, LASEK, TransPRK and FS-LASIK all have certain effects, and have similar results in improving UCVA and increasing visual quality. However, TransPRK and LASEK have more stable biomechanical properties than FS-LASIK, and have better efficacy in improving patients' quality of life.
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AIM: To investigate the risk factors of refractive regression after correction of moderate and high myopia by femtosecond laser assisted in situ keratomileusis(FS-LASIK)for 1 a, and construct prediction model.METHODS: A retrospective analysis was performed on the clinical data of 400 patients(800 eyes)with moderate and high myopia undergoing FS-LASIK correction in Xi'an Gaoxin Hospital from June 2017 to November 2018, and the patients were randomly divided into modeling group(n=300)and verification group(n=100)according to a ratio of 3:1. The modeling group was divided into regression group and non-regression group according to the occurrence of refractive regression at 1 a after surgery. The changes of corneal curvature and corneal thickness were observed. Logistic regression analysis was used to screen the risk factors of refractive regression in patients with moderate and high myopia at 1 a after FS-LASIK correction, and the prediction model was built based on the regression coefficient. Receiver operating curve(ROC)was used to evaluate model differentiation.RESULTS:Refractive regression occurred in 44 eyes of the modeling group and 15 eyes of the verification group at 1 a after surgery. The anterior corneal surface curvature in the modeling group was lower than that in the regression group at 6 and 12 mo after surgery(all P<0.05). The degree of corneal hyperplasia in the regression group was greater than that in the non-regression group at 1, 3, 6 and 12 mo after surgery(all P<0.05). The regression equation of the probability value of refractive regression in patients with moderate and high myopia corrected by FS-LASIK at 1 a after surgery is as follows:P=1/[1+e-(-5.989+0.127×age+2.019×preoperative diopter-0.022×preoperative central corneal thickness+0.043×depth of cutting-1.569×diameter of cutting optical region)], Hosmer-Lemeshow detected the goodness of fit of the regression equation(P=0.818). Internal verification using the modeling group data showed that the area under ROC curve was 0.890(95%CI: 0.843-0.937), the sensitivity was 81.82%, and the specificity was 84.71%. The area under ROC curve was 0.838(95%CI: 0.717-0.959), the sensitivity was 80.00%, and the specificity was 87.57%.CONCLUSIONS:The established risk model has good discriminating validity and can be used to identify the high-risk group of refractive regression at 1 a after FS-LASIK in patients with moderate and high myopia.
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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&#x003C;0.01), and there was no difference in UCVA and SE between the two groups(P&#x003E;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&#x003C;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&#x003C;0.05).CONCLUSIONS:FS-LASIK Xtra has good safety, efficacy and predictability in correcting patients with moderate to high myopia.
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AIM: To explore the effects of femtosecond laser-assisted cataract surgery combined with intraocular lens implantation(FLACS-IOL)on postoperative deviation rate of multifocal intraocular lens(MIOL)and visual quality in cataract patients.METHODS: In the prospective study, 95 patients with cataract(108 eyes)who underwent MIOL implantation in the hospital between January 2021 and December 2022 were enrolled. According to different surgical methods, they were divided into FLACS group(51 cases, 56 eyes)and Phaco group(44 cases, 52 eyes). The operation time, incision diameter of anterior capsule, effective phaco time(EPT), cumulative dissipated energy(CDE), uncorrected distance visual acuity(UCDVA), best corrected distance visual acuity(BCDVA), eccentricity distance of IOL and deviation rate at 3 mo after surgery, total high order aberration(HOA), Trefoil and coma under 3 mm pupil were compared between the two groups.RESULTS: The operation time in the FLACS group was significantly shorter than that in the Phaco group, EPT and CDE were significantly lower than those in the Phaco group(all P<0.05). There was no significant difference in incision diameter of anterior capsule between the two groups(P>0.05). At 1 wk, 3 mo after surgery, UCDVA in the FLACS group was better than that in the Phaco group(all P<0.05). There were significant difference in UCDVA at 1 wk, 3 mo after surgery or BCDVA at 3 mo after surgery between the two groups(P<0.05). At 3 mo after surgery, eccentricity distance of IOL in the FLACS group was shorter than that in the Phaco group, and deviation rate was significantly lower than that in the Phaco group(all P<0.05). Under pupil diameter of 3 mm, HOA, trefoil and coma of whole eyes were decreased in both groups at 3 mo after surgery(P<0.05). At 3 mo after surgery, there were significant differences in HOA and trefoil of whole eyes between the FLACS group and Phaco group(P<0.05), but there was no significant difference in coma at 3 mo after surgery(P>0.05).CONCLUSION: FLACS-IOL can effectively reduce deviation rate of IOL and obtain better visual quality in cataract patients.
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Femtosecond laser-assisted cataract surgery(FLACS)has been used for more than 10 years, with its safety and precision well-verified. In recent years, FLACS has been gradually applied to patients with glaucoma and cataracts, especially those patients with primary angle closure glaucoma(PACG). The unique anatomical characteristics of PACG increase the difficulty of lens extraction and potential complications in conventional phacoemulsification surgery, highlighting the distinct advantages of FLACS in these patients. Recently, the application of FLACS combined with minimally invasive glaucoma surgery(MIGS)in patients with open angle glaucoma, and goniosynechialysis(GSL)in patients with angle-closure glaucoma, and even in patients with filtering blebs after anti-glaucoma surgery, has been reported. The indications for FLACS are increasingly expanding. FLACS can cause a transient intraoperative increase in intraocular pressure(IOP), and ocular parameters can have a certain impact on IOP. The long-term effects on IOP require further research. More attention should be paid to the impact of FLACS on visual function in glaucoma patients and the related complications that may arise. This article reviews the application of FLACS in different types of glaucoma, its effects on IOP and visual function, specific complications, and application prospects.
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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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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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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 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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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 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 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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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.
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AIM: To compare the postoperative efficacy of corneal wavefront-guided femtosecond laser-assisted excimer in situ keratomileusis(FS-LASIK)in the treatment of myopia patients with different degrees of astigmatism and the changes of corneal higher order aberration.METHODS: A total of 133 patients(265 eyes)with myopia and astigmatism were enrolled in this retrospective study. All of them underwent corneal wavefront-guided FS-LASIK surgery for the first time in Aier Eye Hospital(Kunming)from April to October 2020. The patients were divided into three groups according to the different astigmatism: Low astigmatism group: astigmatism ≤1.0D, 62 cases(124 eyes), medium astigmatism group: a total of 54 cases(107 eyes)with astigmatism was 1.25-2.0D, high astigmatism group: a total of 17 cases(34 eyes)with astigmatism ≥2.25D. Visual acuity and refraction were recorded before surgery and 3mo after the surgery and the cornea of the patients was measured by Pentacam three-dimensional corneal topography. Record total higher order aberrations(root mean square), spherical aberration, horizontal coma, vertical coma, horizontal clover and oblique clover in the 6mm diameter range of the cornea. The postoperative effects of the three groups of patients were observed and the changes of corneal high order aberration before and after surgery were compared. RESULTS: The validity index of visual acuity in the three groups of patients was all greater than 1.1 and the residual diopter was all within ±0.30D. The residual diopter in the low astigmatism group was the least than that of the other two groups(P<0.05). At 3mo after surgery, the corneal total higher order aberration, spherical aberration and vertical coma of the three groups were all increased compared with those before surgery(P<0.05). The spherical aberration increase in the high astigmatism group was less than that in the other two groups(P<0.05).CONCLUSION: Corneal wavefront-guided FS-LASIK surgery is safe and effective in the treatment of myopia with different degrees of astigmatism, and the effect is also accurate for patients with high astigmatism. The degree of of preoperative astigmatism is not responsible for increased corneal higher order aberration after the surgery.
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@#AIM:To analyze satisfaction on night vision and its related factors after FS-LASIK in patients with high and low-to-moderate myopia.<p>METHODS:This was a retrospective study. Totally 75 patients(150 eyes)who underwent FS-LASIK in Xi'an No.1 Hospital from June 2018 to September 2019 were included. All subjects were divided into two groups based on spherical equivalent(SE): high myopia group(SE≥-6.00D)and low-to-moderate myopia group(<-6.00D). Six months after surgery, corneal topography and corneal higher-order aberrations(total HOAs, spherical aberrations, coma and trefoil)under 7mm pupil diameter was investigated by Sirius. Patients were required to complete a questionnaire to evaluate satisfaction and night vision symptoms.<p>RESULTS:For the high myopia group and low-to-moderate myopia group, preoperative SE was -7.85±1.27D and -4.57±1.01D respectively. There were significant differences in total HOAs, spherical aberrations and coma(all <i>P</i><0.001)except for the trefoil(<i>P</i>>0.05)between the two groups. Overall satisfaction was 95.3% and 100.0% in high and low-to-moderate myopia group. 18.8% and 9.3% experienced worsen night vision, 51.2% and 40.6% experienced halo, 41.9% and 43.8% experienced starburst, and 18.6% and 15.6% experienced double vision, respectively. Except that there was significant differences in night vision between the two groups(<i>P</i>=0.010), the occurrence of other night vision symptoms were similar and there were no significant differences in any of them(all <i>P</i>>0.05). For all patients, the satisfaction was correlated with preoperative astigmatism and ablation zone(all<i> P</i><0.05), night vision was correlated with preoperative SE, ablation depth, corneal curvature, total HOAs, spherical aberrations and coma postoperatively(all<i> P</i><0.05), star burst was correlated with preoperative total HOAs, coma and postoperative trefoil(all<i> P</i><0.05), double vision was correlated with preoperative astigmatism(<i>P</i><0.05).<p>CONCLUSION: High myopic patient experienced worsen night vision mainly because of increased total HOAs, spherical aberration and coma. However, symptoms such as halo, starburst and double vision were similar in both groups and did not affect overall satisfaction.
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@#In recent years, with the extensive development of phacoemulsification and the gradual application of femtosecond laser technology in the field of cataract surgery, femtosecond laser-assisted cataract surgery(FLACS)has become popular year by year, and has been recognized and promoted by more and more doctors. Femtosecond laser technology has high accuracy, automation and repeatability, so it is quite suitable for cataract surgery characterized by precision operation, it can be used in cataract surgery for corneal incision and limbal incision, anterior capsule incision, lens fragmentation and other key operations. FLACS has broad application prospects and can greatly improve the predictability and safety of surgery. The emergence of FLACS is one of the most important developments in modern cataract surgery. With the continuous development of FLACS, cataract surgery will usher in new technological innovations. However, FLACS are relatively new, and longer term, more comprehensive data are still needed to better demonstrate their effectiveness in the future. We review the current research progress of FLACS.
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Objective:To investigate and compare the changes of modulation transfer function (MTF) after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK).Methods:A cohort study was conducted.One hundred and two myopic patients (102 eyes) who underwent SMILE and FS-LASIK in Tianjin Eye Hospital from December 2015 to June 2016 were enrolled and divided into SMILE group with 53 eyes and FS-LASIK group with 49 eyes according to different surgical methods.The ocular aberrations and corneal morphology of all patients were measured by the Hartman-Shack wave-front analyzer and Pentacam topography before surgery and 1, 3 and 6 months postoperatively.MTF of optic system was calculated and analyzed.The changes of MTF values were compared between the two groups at different time points under different spatial frequencies, after removal of low-order aberrations at postoperative 6 months, and after removal of vertical coma aberration, horizontal coma aberration and spherical aberration in the SMILE group at postoperative 6 months.The study protocol complied with the Declaration of Helsinki and was approved by an Ethics Committee of Tianjin Eye Hospital (No.TJYYLL-2014-17). Written informed consent was obtained from each patient before surgery.Results:Compared with the preoperative MTF, there were significant increases in postoperative 1-, 3- and 6-month MTF at all spatial frequencies in the SMILE group and FS-LASIK group (all at P<0.05). MTF values at all spatial frequencies in the SMILE group were significantly higher than those in the FS-LASIK group at 1, 3, and 6 months after surgery (all at P<0.05), except at 55 c/d and 60 c/d at 6 months postoperatively.The postoperative 6-month MTF values at all spatial frequencies without low-order aberration were higher in the SMILE group than those in the FS-LASIK group, showing significant differences between the two groups (all at P<0.05). In the SMILE group, the postoperative 6-month MTF values at 1 c/d spatial frequency without the horizontal coma aberration and spherical aberration were significantly higher than the preoperative MTF values (both at P<0.01); the postoperative 6-month MTF values at 1 c/d and 3 c/d spatial frequency without vertical coma aberration were significantly higher than the preoperative MTF values (both at P<0.05), and there were no statistically significant differences between the postoperative 6-month MTF values at the other spatial frequencies with and without single high-order aberrations (all at P>0.05). Conclusions:Optic quality has been obviously improved after SMILE and FS-LASIK, and the SMILE is superior to FS-LASIK in the MTF value.
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@#AIM: To investigate the early changes of corneal higher-order aberrations(HOAs)of the anterior surface, posterior surface, and total cornea after femtosecond laser-assisted <i>in situ</i> keratomileusis(FS-LASIK)in mild to moderate myopic and high myopic patients. <p>METHODS: This retrospective study included 129 patients(129 eyes)underwent FS-LASIK surgery from December 2018 to December 2019. Treated eyes were divided into two groups, according to the preoperative spherical equivalent(SE): mild to moderate myopic group(<-6.0D, 76 eyes)and high myopic group(≥-6.0D, 53 eyes). Corneal HOAs of the anterior surface, posterior surface, and total cornea were measured by Pentacam anterior segment analysis system preoperatively and 6mo postoperatively. <p>RESULTS: The tHOAs, spherical aberrations and horizontal coma of the anterior surface and total cornea, significantly increased in both groups 6mo postoperatively(all <i>P</i><0.01). And more tHOAs, spherical aberrations and horizontal coma of the anterior surface and total cornea were induced in high myopic group than mild to moderate myopic group postoperatively(all <i>P</i><0.01). The horizontal coma of the posterior surface, significantly increased in both groups 6mo after operation(all <i>P</i><0.01). And more horizontal coma of the posterior surface were induced in high myopic group than mild to moderate myopic group postoperatively(<i>P</i><0.01). Changes in anterior surface and total corneal tHOAs, spherical aberrations and horizontal coma were related to the SE(all <i>P</i><0.01).<p>CONCLUSION:Anterior and total corneal tHOAs, spherical aberrations and horizontal coma, significantly increased after FS-LASIK, and aberration changes were related to SE. Whereas posterior corneal HOAs remained stable except horizontal coma. The long-term effect should be investigated in the future.
ABSTRACT
@#AIM: To study the effects of small-incision lenticule extraction(SMILE)and femtosecond laser-assisted excimer laser <i>in situ</i> keratomileusis(FS-LASIK)on early postoperative corneal higher order aberrations(HOAs)and visual quality in patients with high myopia. <p>METHODS:Totally 102 patients(204 eyes)with high myopia who underwent corneal refractive surgery between August 2018 and August 2020 in the hospital were selected as study subjects for the prospective study, and they were randomly divided into SMILE group(51 cases, 102 eyes)and FS-LASIK group(51 cases, 102 eyes). The postoperative visual acuity, corneal HOAs and objective visual quality were compared between the two groups, and the correlation between corneal HOAs and objective visual quality was analyzed. <p>RESULTS: At 1mo after surgery, the spherical equivalent degrees in SMILE group and FS-LASIK group were significantly reduced(<i>P</i><0.05), and there was no statistically significant difference in the proportion of patients with postoperative uncorrected visual acuity≥preoperative best corrected visual acuity between the two groups(95.1% <i>vs</i> 92.2%, <i>P</i>>0.05). The corneal HOAs in the two groups were significantly increased(<i>P</i><0.05), and the overall spherical aberration(SA), trefoil and higher HOAs in SMILE group were lower than those in FS-LASIK group(all <i>P</i><0.05). The objective scattering index(OSI)was significantly increased in the two groups while the MTF cutoff frequency(MTF<sub>cutoff</sub>), Strehl Ratio(SR)and contrast visual acuity(VA100%, VA20%, VA9%)were significantly decreased(all <i>P</i><0.05). The OSI of SMILE group was lower than that of FS-LASIK group while MTF<sub>cutoff</sub> and VA9% were higher than those of FS-LASIK group(all <i>P</i><0.05). The corneal HOAs in patients with high myopia were negatively correlated with MTF<sub>cutoff</sub> and were positively correlated with OSI(<i>P</i><0.05).<p>CONCLUSION:Both SMILE and FS-LASIK can effectively correct high myopia, and SMILE has a smaller increase in early postoperative corneal HOAs, and it is of great significance to relieve visual quality impairment.