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As a relatively new procedure, femtosecond laser small incision lenticule extraction (SMIIE) is still in its initial stage.Despite the safety, efficacy, predictability and stability it has showed in refractive error correction, there are still reports of intraoperative complications resulting in different clinical outcomes in SMILE.SMILE includes the production of lenticule by femtosecond laser, the separation and extraction of lenticule, and intraoperative complications may occur in every step.The production of the lenticule is completely dependent on the femtosecond laser, so complications related to femtosecond lasers are inevitable, such as suction loss, opaque bubble layer and black spots.Separation and extraction of the lenticule relies on the experience and surgical skills of surgeon, during which, torn corneal cap, difficult lenticule extraction, lenticule remnants, bleeding and lenticule decentration may occur.In this article, the categories, reasons, management and effects of intraoperative complications on outcome in SMILE were summarized to improve the ability of ophthalmologists to handle intraoperative incidents and enhance surgical safety.
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Objective:To evaluate the effectiveness and safety of transepithelial photorefractive keratectomy (TransPRK) assisted by smart pluse technology (SPT) for the correction of high myopia.Methods:An observational case series study was conducted.Sixty high myopic patients (107 eyes) with spherical equivalent (SE)≥-6.0 D who received TransPRK assisted by SPT from January to December 2016 in Eye Hospital of Wenzhou Medical University were enrolled.Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) of the patients were examined and recorded in logarithm of the minimum angle of resolution (LogMAR) units, and refraction was examined with a subjective refractometer.The healing of corneal epithelium and corneal haze was observed with a slit lamp.Intraocular pressure (IOP) was measured with the non-contact tonometer.Safety index (SI) and efficacy index (EI) were analyzed.The follow-up time was 12 months.This study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Eye Hospital of Wenzhou Medical University (No.2019-197-k-177). Written informed consent was obtained from each patient prior to any medical examination.Results:The mean epithelial healing time was (3.77±1.02) days.There were statistically significant differences in UCVA and BCVA between before and after surgery ( Z=380.812, 267.313; both at P<0.001). And the 7-day, 6-month, and 12-month postoperative BCVA were better than preoperative BCVA, showing statistically significant differences (all at P<0.05). Mean SI was 1.10±0.12, and mean EI was 1.05±0.17 at 12 months after surgery.There was no significant difference between the attempted SE before surgery (-8.02±1.36)D and the achieved SE at 12 months after surgery (-8.04±1.51)D ( P=0.523). SE in the predictive range within ±0.50 D accounted for 79% (85/107) and that within ±1.0 D accounted for 92% (98/107). The IOP was slightly increased in 3 eyes at 7 days and 7 eyes at 1 month after surgery, respectively, which returned to normal after the use of ophthalmic solution for lowing IOP.The incidence of haze severer than grade 1 was less than 1% (1 eye), and haze gradually disappeared after application of drugs. Conclusions:TransPRK assisted by SPT for high myopia shows good safety, effectiveness and predictability.It is an ideal corneal surface surgery to correct high myopia.
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Laser corneal refractive surgery is currently the most mainstream surgery to correct refractive errors.In recent years,the laser corneal refractive surgery has been developed rapidly in China.Femtosecond laser small incision lenticule extraction (SMILE) and the femtosecond laser flap laser in situ keratomileusis (LASIK) are greatly improving the safety of the laser lamellar corneal refractive surgery,and trans-epithelial photorefractive keratectomy (Trans PRK) is also taking the surface ablation of excimer laser to a new level.Compared with traditional excimer laser corneal refractive surgery,the above methods are more safe,stable and reliable.Trans PRK,SMILE and femtosecond flap LASIK combined with riboflavin corneal cross-linking provides a safe guarantee for the myopicpatients with thin cornea and abnormal corneal topography.As rapid progress and upgrading of laser corneal refractive surgery technologies,selection of operation methods is a new challenge.Ophthalmologists should comprehensively evaluate the corneal anatomical characteristics,individual needs of patients,performance of operating equipment andindications of different surgeries to pay more attention to the precise and personalized selection of laser corneal refractive surgery to improve the postoperative visual quality of patients with ametropia.
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Requirements for cataract surgery have gradually increased from the original rehabilitation procedure to personalized refraction surgery.Femtosecond laser-assisted cataract surgery is being widely used because of its precision of incision,accuracy of capsule cutting and high efficiency of nuclear fracturing in recent year.Currently some operating systems of femtosecond laser-assisted cataract surgery include LenSx,Catalys,LenSAR and Victus,and they are different in the design of contact interfaces,video and operating bed and therefore present different working methods.Ophthalmologists should be aware of the differences of these operating systems and accurate assess the clinical findings of patients in order to consider the preciseness,accuracy,efficiency of incision,capsulorhexis and nucleus fragmentation to avoid the intraoperative and postoperative complications.
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Background Recently,small incision lenticule extraction (SMILE) procedure is used to correct myopia.The clinical safety and efficiency of SMILE have been approved,but its predictability to corneal ablation depth is brought into focus.Objective This study was to compare the predictability of ablation depth in central cornea between SMILE and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia.Methods A nonrandomized controlled clinical study was performed.Two hundred and seventy eyes of 135 myopic patients who were going to receive corneal refractive surgery were included in Beijing Tongren Hospital from October 2015 to May 2016.SMILE and FS-LASIK were performed on 138 eyes of 69 patients and 132 eyes of 66 patients matched in demography respectively under the informed consent.Central corneal thickness was measured by RTVue FD-OCT before and 1 week after surgery.The refractive power,actual ablation depth (difference of central corneal thickness before and after surgery) and central corneal cutting error (difference between theoretically expected ablation depth and real ablation depth) were intergrouply compared,and the correlation of real ablation depth with theoretically expected ablation depth was assessed.Results No significant difference was found in spherical power,astigmatic power and spherical equivalent after surgery between SMILE group and FS-LASIK group (t =-1.826,-1.405,-1.420,all at P＞0.05).The actual ablation depth was (76.96± 15.27)μm in the SMILE group,which was significant lower than (96.76± 16.52) μm of theoretically expected ablation depth (t =-23.016,P ＜ 0.01);however,there was no significant difference in the FS-LASIK group between actual and expected ablation depth ([77.92 ± 18.69] μm versus [77.42± 15.60] μm) (t =-0.604,P =0.547).The central corneal cutting error was (20.55 ± 8.51) μm in the SMILE group and (7.17±5.97) μm in the FS-LASIK group,showing a significant difference between them (t=14.950,P＜0.01).The positive linear correlations were seen between actual and expected ablation depth in both SMILE group and FS-LASIK group (r=0.799,0.867,both at P＜0.01).The actual ablation depth was increased over expected ablation depth,with the regression equations of Y=3.892+0.749X in the SMILE group and Y=3.443 + 0.957X in the FS-LASIK group.Conclusions The actual corneal ablation depth is less than expected corneal ablation depth in SMILE procedure,while in FS-LASIK procedure,the actual corneal ablation depth appears to be consistent with the expected one,inferring a good predictability in corneal ablation depth in FS-LASIK surgery.
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In recent years,corneal refractive surgery continues to develop with becoming to be one of the most prevalent utilizations of correction of many patients and brings about better visual quality for ametropic patients.Meanwhile,some patients are subjected to optical complications,and poor night vision is one of the most serious problems which are complained by sufferers after refractive surgery,such as glare,halo and reduce of contrast sensitivity,and the affective factors include age,pupil diameter,high order aberation,scattering,pre-estimated diopter,corneal healing,individual sensitivity to surgery,which are supposed to attract the attention of the majority of clinicians and researchers,at the same time.Ophthalmic clinical doctors and researchers only fully understand the mechanism of the above factors and explore the corresponding measures in order to purposefully treat these complications.In addition,ophthalmologists should be aware of the interaction of these factors and their relationship with individual sensitivity and explore the impact of postoperative visual impairment and the way to avoid them in clinical practice inorder to improve the visual quality by controlling the postoperative optical complications.
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Background The current evaluation of corneal optical quality after small incision lenticule extraction (SMILE) is based on the single factor,such as scattering,diffraction or aberration,and all of them are not comprehensive and objective methods.Modulation transfer function (MTF) and Strehl ratio (ST) are novel parameters of corneal optical quality,which can be used to assess the optical quality comprehensively.Objective This study was to evaluate the change of MTF and SR under the photopic and scotopic environment (3 mm and 6 mm pupil size,respectively) after SMILE procedure.Methods The study protocol was approved by Ethic Committee of Tianjin Eye Hospital,and written informed consent was obtained from each patient before any medical procedure.A series cases-observational study with self-control design was carried out.Sixty-three eyes of 32 myopia or myopic astigmatism patients who underwent SMILE surgery in Tianjin Eye Hospital were included from December 2013 to March 2014.The uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA) (LogMAR),the effective index (postoperative UCVA/preoperative BCVA) and refractive diopter were examined,and the MTF,SR and root mean square (RMS) on the anterior corneal surface were measured under the 3 mm and 6 mm pupil size at different spatial frequencies (10,20,30,40,50 and 60 c/d) by Sirius anterior analyzer before surgery and 1 week,1 month and 3 months after surgery,respectively.Results UCVA was ≥0.8 in 59,62 and 63 eyes in 1 week,1 month and 3 months after SMILE,with the percentage of 93.65％,98.41％ and 100％,and the effective index was 1.104± 0.128,1.126±0.145 and 1.158±0.208,respectively.The refractive diopter was normal in the eyes at postoperative 3 months.The MTFs of various spatial frequencies on the vertical and horizontal meridian under the 3 mm pupil size after SMILE were significantly higher than those before SMILE,while under the 6 mm pupil size,the MTFs were higher only on vertical meridian and 10,20,30 and 40 e/d,and there were not significant differences on the horizontal meridian (all at P＜0.05).The SRs under the 3 mm and 6 mm pupil size showed increasing softly after surgery in comparison with before surgery,and the SRs were higher under the 3 mm pupil size than those under the 6 mm pupil size at various time points (all at P＜0.05).There were not significant differences in RMS among different time points under both 3 mm pupil size and 6 mm pupil size (3 mm pupil size:F =1.348,P =0.184;6 mm pupil size:F=1.990,P=0.137).Conclusions SMILE provides a great improvement in corneal optical quality for myopia or myopic astigmatism patients,which is more distinct in photopic condition than that in scotopic condition.
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Background Corneal reinnervation of subbasal nerve plexus have been found after small incision lenticule extraction(SMILE).However,there were few reports about corneal reinnervation mode and dynamic changes at the corneal cap in different time points postoperation.Objective The aim of this study was to evaluate the corneal reinnervation at the cap margin after SMILE.Methods The clinical data of 32 myopic eyes of 16 patients who received SMILE incision lenticule extraction surgery in Affiliated Eye Hospital of Shandong Medical College from April 2014 to April 2015 were retrospectively analyzed.The following-up was carried in 1 week,1 month,3 months and 6 months after surgery,and in-vivo confocal microscopy was used to acquire images of the central corneal subbasal nerve plexus before and after surgery,with the scan range of 0.4 mm×0.4 mm,from which nerve density and nerve tortuosity were evaluated using Image-Pro Plus imaging analysis software.The overall length of nerve fibers at the central cornea was measured to assess the subbasal nerve density,and the repair of nerve fibers at cap was observed.Results The corneal subbasal nerve density was (19 687.45 ± 1 147.59),(10 500.46 ± 1 056.22),(12 833.40-± 1 047.98),(13 564.04-± 1 173.01) and (14 661.35-±941.92) μm/mm2 in preoperation and postoperative 1 week,1 month,3 months,6 months,respectively,with a significant difference among different time points (F =319.44,P=0.000),and the corneal subbasal nerve densitis in postoperative time points were significantly reduced in comparison with the preoperation,and corneal subbasal nerve densities were gradually increased after surgery as the extending of time,showing significant differences between different time points (all at P＜ 0.01).Abundant corneal subbasal nerve fibers were seen with the near normal morphology after surgery.However,the fragments and disaggregation of nerve fibers were found at the incision of cap margins,and some nerve fibers extended toward the inner cap at the non-incision of cap margins 1 week after surgery.In 3-6 months after SMILE,the continuous extension of nerve fibers was exhibited under the confocal microscope.Conclusions Six months after surgery,less invasive SMILE technique can remain the superficial corneal nerve fibers.Corneal innervation shows a radiate mode from peripheral cornea outside toward inside of the cap.The subbasal never fiber density is gradually increased with the extending of time after SMILE.
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Background Keratectasia after laser in situ keratomileusis (LASIK) is a rare but severe complication,which threatens the visual acuity and corneal strength.Corneal collagen crosslinking (CXL) is a new therapy that increases the security and decreases the risk of complication.However,the effectiveness and safety of LASIK-CXL is still need to be concerned.Objective This study was to evaluate the safety of LASIK-CXL for myopia and astigmatism with thin cornea.Methods A prospective cohort study was designed.A total of 128 eyes of 64 patients with thin corneal and myopic astigmatism enrolled in Beijing Tongren Eye Center from January 2014 to January 2015.The patients were assigned to LASIK group (74 eyes of 37 patients) and LASIK-CXL group (54 eyes of 27 patients).Refractive surgery was performed by Visumax femtosecond lasrer and VISX S4 excimer laser.Eyes of LASIK-CXL group applied accelerated CXL immediately after LASIK.The follow-up was 6 months.Manifest refraction,uncorrected (UDVA) and corrected distance visual acuity (CDVA),average keratometry values (AveK),anterior segment OCT (AS-OCT),corneal hysteresis (CH) and corneal resistance factor (CRF) were examined before and after operation.This research passed through Ethics Committee of Beijing Tongren Hospital.Results The spherical equivalent (SE) of the LASIK group and LASIK-CXL group were (-6.49 ±2.41)D and (-6.97 ±2.41) D before operation and decreased to (-0.68 ±0.88) D and (-0.75 ±0.94) D 6 months after operation.The UDVA (LogMAR) was 1.18±0.28 and 1.05±0.38 before operation and elevated to-0.06±0.09 and-0.03±0.186 months after operation in the LASIK group and LASIK-CXL group.The preoperative AveK values were (44.37 ±1.46) D and (44.47± 1.50)D in the LASIK group and LASIK-CXL group and reduced to postoperative (39.30±2.06) D and (38.66± 1.80) D.The preoperative SRI of LASIK group and LASIK-CXL group were 0.25 ±0.21 and 0.24±0.22,which increased to 0.29±0.24 and 0.28±0.24.The SAI values were 0.36±0.16 and 0.39±0.15 before operation,which increased to 0.57 ±0.31 and 0.75 ±0.376 months after operation,and the SAI value of the LASIK-CXL group was significantly higher than that of LASIK (F =10.220,P--0.002).CRF values of LASIK and LASIK-CXL were (8.44±1.44)mmHg and (8.63±1.35) mmHg in preoperation,which decreased to (5.74±1.31) mmHg and (6.25± 1.24) mmHg in postoperation.The result of LASIK-CXL was higher than that of LASIK (F=8.650,P =0.040).CH values were 8.78 ± 1.51 and 8.69 ± 1.62 in preoperation,which decreased to (7.23 ± 1.08) mmHg and (6.50±1.32)mmHg.The value of LASIK-CXL was lower than that of LASIK (F =5.860,P =0.017).The mean depth of demarcation line was (228.45±28.24) μm (range 165 to 310 μm) on OCT,which was presented in 45 eyes (81.82％) at 1 month in postoperation.Conclusions Accelerated CXL with FS-LASIK is effective and safe in improving visual acuity in myopic astigmatism patients with thin cornea,which also can increase the rigidity of the cornea.
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Safety,efficacy and predictability of corneal refractive surgery have greatly improved as the advancement of the operating technology and equipment.Laser corneal refractive surgeries include excimer laser photorefractive keratectomy (PRK),laser-assisted subepithelial keratomileusis (LASEK),laser in situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE).No matter what kind of operation method,its ultimate goal is to increase the comfort level and improve visual quality.With the surgery skills improving,retinal drug use is a primary factor affecting the safety of laser corneal refractive surgery.Ophthalmologists should strictly master indications and administration of commonly used drugs in postoperative eyes to prevent drug-related eye diseases.In addition,eye doctors also should understand the postoperative complications and topical administration of eye drops.It is important to pay attention to the standard surgical operation and rational drug use after corneal refractive surgery,which can enhance the visual quality and comfort and reduce the complication.
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Background Integrated transepithelial photorefractive keratectomy (TransPRK) is a new kind of surface ablation and has a fast reepithelialization and uncorrective visual acuity (UCVA) recovery as well as slighter postoperative pain,and epipolis laser in situ keratomileusis (Epi-LASIK) has been recognized to be an effective method for myopia.But there have been few studies to evaluate the dynamic change of the corneal biomechanical properties and posterior corneal elevation after TransPRK.Objective This study was to assess and compare the effectiveness and safety between TransPRK and Epi-LASIK for myopia with thin cornea.MethodsThis study was approved by Ethic Committee of Jinan Mingshui Eye Hospital,and written informed consent was obtained from each patient.In this prospective non-randomized controlled study,93 right eyes of 93 myopic patients with the central corneal thickness 460 to 500 μm were included in Jinan Mingshui Eye Hospital from June to December 2013 under the informed consent.The eyes were divided into TransPRK group for 46 eyes and Epi-LASIK group for 47 eyes.UCVA,manifest refraction,haze,corneal biomechanical properties,posterior corneal elevation,Qvalue and corneal high order wavefront aberration were analyzed before and 1 week,1 month,3 months and 6 months after operation,respectively,and the examination results were compared between the two groups.Results There was no statistically significant difference in the eyes of postoperative UCVA and manifest refraction between the TransPRK group and the Epi-LASIK group at various time points (all at P＞0.05).Six months after surgery,the percentage of eyes with UCVA of 1.0 or better was 93.9％,and 90.9％ eyes exhibited the targeted refraction in ± 1.00 D in the TransPRK group.Corneal haze was most obvious 1 month after surgery in both groups,with the incidence of 32.6％ (15/46) in the TransPRK group and 17.4％ (8/47) in the Epi-LASIK group,but no significant difference was found in the eye numbers with haze between the two groups (x2 =2.841,P =0.092).No significant differences were seen in the corneal hysteresis(CH) values and corneal resistance factor(CRF) values between the two groups (CH:Fgroup =0.000,P =0.999;CRF:Fgroup =0.110,P =0.741),however,the postoperative CH values and CRF values were significantly declined in comparison with preoperative ones,with significant differences among various time points (CH:Ftime =103.658,P =0.000;CRF:Ftime =132.008,P =0.000),while there were no remarkable differences between any two time points in postoperation (all at P＞0.05).Posterior corneal surface height shifted rearward 1 week,1 month,3 months and 6 months after surgery,showing remarkable differences in comparison with before surgery in both groups (Ftime =12.868,P =0.001),but no significant differences between the two groups (Fgroup =1.923,P=0.169).No significant differences were found in Q-value between the two groups (Fgroup =0.191,P=0.663).Root mean square (RMS) and spherical aberration values elevated in postoperation compared with preoperation,with significant differences between them(all at P＜0.01),but the comparison between intergroup was insignificant (RMS:Fgroup =0.299,P =0.586;Spherical aberration:Fgroup =1.290,P =0.259).Conclusions TransPRK for myopia with thin cornea is safe and stably effective like Epi-LASIK.TransPRK affects corneal biomecbanical properties early after surgery but the effect gradually lessens over time.The posterior corneal elevation shows a tiny backward displacement,while posterior corneal asphericity has no change.
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Purpose: To compare optical and visual quality of implantable collamer lens (ICL) implantation and femtosecond laser in situ keratomileusis (F-LASIK) for myopia. Methods: The CRX1 adaptive optics visual simulator (Imagine Eyes, Orsay, France) was used to simulate the wavefront aberration pattern after the two surgical procedures for -3-diopter (D) and -6-D myopia. Visual acuity at different contrasts and contrast sensitivities at 10, 20, and 25 cycles/degree (cpd) were measured for 3-mm and 5-mm pupils. The modulation transfer function (MTF) and point spread function (PSF) were calculated for 5-mm pupils. Results: F-LASIK MTF was worse than ICL MTF, which was close to diffraction-limited MTF. ICL cases showed less spread out of PSF than F-LASIK cases. ICL cases showed better visual acuity values than F-LASIK cases for all pupils, contrasts, and myopic treatments (p<0.05). No statistically significant differences were found in contrast sensitivities between ICL and F-LASIK cases with -3-D myopia for both pupils for all evaluated spatial frequencies (p>0.05). For -6-D myopia, however, statistically significant differences in contrast sensitivities were found for both pupils for all evaluated spatial frequencies (p<0.05). Contrast sensitivities were better after ICL implantation than after F-LASIK. Conclusions: ICL implantation and F-LASIK provide good optical and visual quality, although the former provides better outcomes of MTF, PSF, visual acuity, and contrast sensitivity, especially for cases with large refractive errors and pupil sizes. These outcomes are related to the F-LASIK producing larger high-order aberrations. .
Objetivo: Comparar a qualidade óptica e visual da lente implantável de collamer (ICL) e da ceratomileuse in situ com laser de femtosegundo (F-LASIK) na correção de miopia. Métodos: O simulador visual de óptica adaptativa CRX1 (Imagine Eyes, Orsay, França) foi usado para simular o padrão de aberração de frentes de onda, depois de dois procedimentos cirúrgicos: implante de ICL e tratamento F-LASIK para -3 e -6 D. A acuidade visual em diferentes contrastes e sensibilidade ao contraste em 10, 20 e 25 ciclos/grau (cpd) foram medidos para pupilas de 3 e 5 mm. A função de transferência de modulação (MTF) e a função de espalhamento de ponto (PSF) foram calculados para a pupila de 5 mm. Resultados: A MTF do F-LASIK foi pior do que a do ICL, que estava perto da MTF do limite de difração. A ICL apresentou menor espalhamento do PSF do que o F-LASIK. ICL apresentou melhores valores da acuidade visual do que F-LASIK para todas as pupilas, contrastes e tratamentos miópicos (p<0,05). Não foram encontradas diferenças estatisticamente significantes na sensibilidade ao contraste entre ICL e F-LASIK de -3 D, para ambas as pupilas e quaisquer frequências espaciais avaliadas (p>0,05). Por outro lado, para -6 D, diferenças estatisticamente significativas na sensibilidade ao contraste foram encontrados para ambas as pupilas e todas as frequências espaciais avaliadas (p<0,05). Sensibilidade ao contraste foi melhor após o implante da ICL que após o F-LASIK. Conclusões: ICL e F-LASIK proporcionam uma boa qualidade óptica e visual, embora a ICL oferece melhores resultados de MTF, PSF, acuidade visual e sensibilidade ao contraste, especialmente para grandes erros de refração e tamanhos de pupila. Estes resultados estão relacionados ao procedimento F-LASIK que induz maiores aberrações ...