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Wang Z, Li M, Ji H, Chen H, Sang A, Cheng X, Li J, Yu Y. Comparison of risk factors for OBL in FS-LASIK and SMILE correction for myopia and myopia astigmatism. Graefes Arch Clin Exp Ophthalmol 2024; 262:1925-1931. [PMID: 38091059 DOI: 10.1007/s00417-023-06336-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/26/2023] [Accepted: 11/30/2023] [Indexed: 05/22/2024] Open
Abstract
BACKGROUND To find out the incidence and risk factors of opaque bubble layer (OBL) in eyes with myopia and myopic astigmatism following femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE). METHODS A total of 1076 eyes from 569 patients who had FS-LASIK or SMILE were included in the retrospective research. For each kind of surgery, eyes were separated into two groups: "OBL" groups and "no OBL" groups. In the FS-LASIK group, eyes that developed OBL were split into "hard OBL" and "soft OBL" groups. The incidence and size of OBL were analyzed after watching the surgical procedure videotaped during the operation and taking screenshots. Surgical parameters, including sphere, cylinder, keratometry, corneal thickness, flap thickness, cap thickness, lenticule thickness, and visual acuity, were compared. RESULTS In the FS-LASIK surgery, the incidence of OBL was 63.2% (347 eyes). A thicker central corneal thickness (CCT) was the only independent risk factor affecting the OBL area (β = 0.126, P = 0.019). One hundred and thirty of these eyes had hard OBL, and the flap thickness of these eyes was thinner than that of those with soft OBL (P = 0.027). In the SMILE group, 26.6% (140 eyes) developed OBL. A higher flat keratometry (K) and a thicker residual stromal thickness (RST) were risk factors affecting the OBL area (β = 0.195, P = 0.024; β = 0.281, P = 0.001). CONCLUSION The incidence of OBL differs between the FS-LASIK surgery and the SMILE surgery. There are differences in the factors influencing OBL between the two surgeries.
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Affiliation(s)
- Zichen Wang
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China
| | - Mingrui Li
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China
| | - Haixia Ji
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China
| | - Hui Chen
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China
| | - Aimin Sang
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China
| | - Xinliang Cheng
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China
| | - Jun Li
- Department of Dermatology, Nantong First People's Hospital, Second Affiliated Hospital of Nantong University, Nantong, 226001, China
| | - Ying Yu
- Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, No. 20, Xisi Road, Nantong City, 226001, Jiangsu Province, China.
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Zhao Y, Zhao W, Wang J, Zhang Z, Zhou X, Zhao J. Characteristics of disk halo size and its correlation with lenticule quality in small incision lenticule extraction for moderate to high myopia. Graefes Arch Clin Exp Ophthalmol 2024; 262:313-321. [PMID: 37405512 PMCID: PMC10805804 DOI: 10.1007/s00417-023-06133-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 07/06/2023] Open
Abstract
PURPOSE To investigate changes in disk halo size after small incision lenticule extraction (SMILE) and the correlation between halo size and lenticule quality in moderate to high myopia. METHODS Thirty eyes of 30 consecutive patients (mean age, 24.9 ± 4.5 years; mean spherical equivalent, -6.85 ± 1.18 D) undergoing SMILE were included in this prospective study. Lenticule surface quality was accessed with a scanning electron microscopy by a scoring system. Halo size was measured preoperatively and at 1, 3, and 6 months postoperatively. Multiple linear regression analysis was performed to explore associations between halo size and a range of factors, including lenticule quality. RESULTS Disk halo size increased slightly at 1 month and then recovered continually from 3 to 6 months postoperatively, with no difference between halo size during the preoperative period and at 6 months postoperatively (P > 0.05). One month after SMILE, halo size (1 cd/m2, 5 cd/m2) was associated only with uncorrected distance visual acuity (P ≤ 0.004). A halo size of 5 cd/m2 at 3 months postoperatively correlated with the anterior surface quality of the lenticule (P = 0.046). At 6 months postoperatively, a halo size of 1 cd/m2 was associated only with the baseline, accounting for 11.9% of the variability (P = 0.041); no correlations were found for the halo size of 5 cd/m2. CONCLUSIONS Disk halo size after SMILE was enlarged at an early stage postoperatively and subsequently declined to the baseline level during a 6-month follow-up. The quality of the lenticule surface influenced halo size changes in the early phase.
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Affiliation(s)
- Yu Zhao
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Wuxiao Zhao
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Center for Optometry and Visual Science, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Academy of Medical Sciences, Nanning, China
| | - Jifang Wang
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Zhe Zhang
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xingtao Zhou
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
| | - Jing Zhao
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
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Yang S, Wang H, Chen Z, Li Y, Chen Y, Long Q. Possible risk factors of opaque bubble layer and its effect on high-order aberrations after small incision Lenticule extraction. Front Med (Lausanne) 2023; 10:1156677. [PMID: 38179268 PMCID: PMC10765512 DOI: 10.3389/fmed.2023.1156677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 11/30/2023] [Indexed: 01/06/2024] Open
Abstract
Purpose To evaluate the possible risk factors of opaque bubble layer (OBL) formation in small incision lenticule extraction (SMILE) surgery and its effects on visual quality. Methods Fifty-six eyes from 28 patients were included in this study. The preoperative parameters and intraoperative designs were recorded. Corneal high-order aberrations (HOAs), point spread function (PSF), and modulation transfer function (MTF) were measured using iTrace at pre-operation, 1 week, 1 month, and 3 months after SMILE. Generalized Estimating Equation and Linear Mixed Effects Model were employed for statistical analysis. Results The mean OBL area in SMILE surgery was 2.75% ± 1.25%. The patients were divided into groups based on whether the OBL was greater than the mean group or less than the mean group. Compared to the group with a smaller OBL area, the group with the larger OBL area had steeper corneal curvature and thinner cap thickness, the OBL area was positively correlated with the preoperative keratometry (r = 0.21, p = 0.04) and preoperative spherical value (r = 0.47, p = 0.01). The group with the larger OBL area induced more corneal SA and trefoil at 1 week postoperatively, but the difference was not significant at 1 month and 3 months postoperatively. Conclusion A steep corneal curvature, thin cap thickness, and high preoperative spherical value are possible risk factors for OBL formation in SMILE surgery. The OBL increased the ocular and corneal HOAs postoperatively for a short period (1 week), while it did not affect the long-term outcomes.
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Affiliation(s)
| | | | | | | | - Youxin Chen
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qin Long
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Zhou N, Chen X, Yin N. Effect of corneal flap thickness on opaque bubble layer formation in Visumax FS-LASIK using GEE analysis. Heliyon 2023; 9:e21547. [PMID: 37964822 PMCID: PMC10641232 DOI: 10.1016/j.heliyon.2023.e21547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/16/2023] Open
Abstract
Introduction This study aimed to investigate two types of corneal flap thickness on opaque bubble layer (OBL) formation in Visumax femtosecond laser-assisted stromal for situ keratomileusis (FS-LASIK). Methods This retrospective study analyzed 203 eyes of 103 patients (32 men and 71 women) who underwent Visumax FS-LASIK between January 2020 and June 2020, and according to corneal flap thickness, they were divided into the 100-μm group (64 eyes) and the 110-μm group (139 eyes). Anterior-segment examination revealed no abnormal findings. Preoperatively, intraocular pressure (IOP), central corneal thickness (CCT), residual stromal thickness (RST), spherical power, cylindrical power, flat keratometry (K1), steep keratometry (K2), and biomechanical parameters including deformation amplitude (DA) ratio, Integrated Radius, stiffness parameter at first applanation (SP-A1), and Ambrosio relational thickness to the horizontal profile (ARTh) were evaluated. Primary outcomes were the incidence of OBL formation in the two groups compared by the Chi-square test and the correlation between the incidence of OBL and the above preoperative data by Spearman's Rho test. Secondary outcomes were the comparisons corrected by the generalized estimating equation (GEE) model. Results The incidence of OBL formation in the 100-μm group was 59.4 %, which was higher than that in the 110-μm group (23.0 %) with a significant difference (χ2 = 25.635, P < 0.001). The thinner corneal flap thickness (r = -0.355, P < 0.001) and higher spherical power (r = -0.142, P < 0.05) correlated with OBL formation. Higher K1 (r = 0.217, P < 0.01) and K2 (r = 0.198, P < 0.01) also correlated with OBL formation. The results of the GEE correction analysis showed higher rates of OBL formation in the 100-μm group (odds ratio [OR] = 4.704, 95 % CI 1.681-13.161, P < 0.01). Conclusions OBL was more likely to occur with the 100-μm corneal flap than with the 110-μm corneal flap in Visumax FS-LASIK. The risk of OBL formation in the 100-μm group was 4.704 times higher than that in the 110-μm group.
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Affiliation(s)
- Na Zhou
- Department of Refractive Surgery, Dongguan Aier Eye Hospital, China
| | - Xiaobei Chen
- Department of Refractive Surgery, Dongguan Aier Eye Hospital, China
| | - Na Yin
- Department of Refractive Surgery, Dongguan Aier Eye Hospital, China
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Wan Q, Yue S, Tang J, Wei R, Tang J, Ma K, Yin H, Deng YP. Prediction of Early Visual Outcome of Small-Incision Lenticule Extraction (SMILE) Based on Deep Learning. Ophthalmol Ther 2023; 12:1263-1279. [PMID: 36826752 PMCID: PMC10011351 DOI: 10.1007/s40123-023-00680-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/07/2023] [Indexed: 02/25/2023] Open
Abstract
INTRODUCTION Deep learning (DL) has been widely used to estimate clinical images. The objective of this project was to create DL models to predict the early postoperative visual acuity after small-incision lenticule extraction (SMILE) surgery. METHODS We enrolled three independent patient cohorts (a retrospective cohort and two prospective SMILE cohorts) who underwent the SMILE refractive correction procedure at two different refractive surgery centers from July to September 2022. The medical records and surgical videos were collected for further analysis. Based on the uncorrected visual acuity (UCVA) at 24 h postsurgery, the eyes were divided into two groups: those showing good recovery and those showing poor recovery. We then trained a DL model (Resnet50) to predict eyes with early postoperative visual acuity of patients in the retrospective cohort who had undergone SMILE surgery from surgical videos and subsequently validated the model's performance in the two prospective cohorts. Finally, Gradient-weighted Class Activation Mapping (Grad-CAM) was performed for interpretation of the model. RESULTS Among the 318 eyes (159 patients) enrolled in the study, 10,176 good quality femtosecond laser scanning images were obtained from the surgical videos. We observed that the developed DL model achieved a high accuracy of 96% for image prediction. The area under the curve (AUC) value of the DL model in the retrospective cohort was 0.962 and 0.998 in the training and validation datasets, respectively. The AUC values in two prospective cohorts were 0.959 and 0.936. At the video level, the trained machine learning (ML) model (XGBoost) also accurately distinguished patients with good or poor recovery. The AUC value of the ML model was 0.998 and 0.889 in the retrospective cohort (training and test datasets, respectively) and 1.000 and 0.984 in the two prospective cohorts. We also trained a DL model which can accurately distinguish suction loss (100%), black spots (85%), and opaque bubble layer (96%). The Grad-CAM heatmap indicated that our models can recognize the area of scanning and precisely identify intraoperative complications. CONCLUSIONS Our findings suggest that artificial intelligence (DL and ML model) can accurately predict the early postoperative visual acuity and intraoperative complications after SMILE surgery just using surgical videos or images, which may display a great importance for artificial intelligence in application of refractive surgeries.
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Affiliation(s)
- Qi Wan
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Shali Yue
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Jing Tang
- Department of Ophthalmology, The People's Hospital of Leshan, Leshan City, Sichuan Province, China
| | - Ran Wei
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Jing Tang
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Ke Ma
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China.
| | - Hongbo Yin
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Ying-Ping Deng
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China.
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Brar S, Ganesh S, Gautam M, Devi RC. Comparison of Clinical Outcomes and Visual Quality Using a Medium Versus Small Contact Glass in Patients Undergoing SMILE With Large Corneal Diameters. J Refract Surg 2021; 37:150-157. [PMID: 34038297 DOI: 10.3928/1081597x-20201222-02] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the clinical outcomes and visual quality using a small (S) versus medium (M) size contact glass in eyes with large white-to-white (WTW) distance undergoing bilateral small incision lenticule extraction (SMILE) for myopia correction. METHODS This contralateral eye study involved 60 eyes of 30 patients (mean age: 27.20 years) undergoing bilateral SMILE for myopia/myopic astigmatism with a WTW distance of 12 mm or greater in both eyes, which were randomized to receive treatment with an S-contact glass in one eye and an M-contact glass in the fellow eye. Opaque bubble layer (OBL) was graded using a new grading system. On postoperative 1 day, 2 weeks, and 3 months, UDVA, CDVA, contrast sensitivity, Objective Scatter Index, and modulation transfer function cut-off values were compared between the two groups. RESULTS The mean OBL score was significantly lower in the S-contact glass group (28.18%) compared to the M-contact glass group (67.13%) (P < .01). At 1 day postoperatively, the UDVA, Objective Scatter Index score, and contrast sensitivity values for all spatial frequencies were significantly better in eyes treated with the S-contact glass compared to the M-contact glass (P ⩽ .05). At 3 months postoperatively, however, the UDVA, Objective Scatter Index score, modulation transfer function cut-off, and contrast sensitivity values were comparable for both groups. No eye in either group had intraoperative complications such as suction loss, incision/lenticule tears, or lenticule retention. CONCLUSIONS In corneas with a WTW distance of 12 mm or greater, docking with the S-contact glass resulted in significantly better immediate visual results due to less OBL formation and smoother tissue dissection compared to the M-contact glass. [J Refract Surg. 2021;37(3):150-157.].
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Asif MI, Bafna RK, Mehta JS, Reddy J, Titiyal JS, Maharana PK, Sharma N. Complications of small incision lenticule extraction. Indian J Ophthalmol 2020; 68:2711-2722. [PMID: 33229647 PMCID: PMC7856979 DOI: 10.4103/ijo.ijo_3258_20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.
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Affiliation(s)
- Mohamed Ibrahime Asif
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Rahul Kumar Bafna
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Jodhbir Singh Mehta
- Singapore Eye Research Institute; Singapore National Eye Centre, 168751; Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Medical School, Singapore
| | - Jagadesh Reddy
- Cataract and Refractive Services, Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Jeewan Singh Titiyal
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Prafulla K Maharana
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Namrata Sharma
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Freidank S, Vogel A, Linz N. Optical Vortex Beam for Gentle and Ultraprecise Intrastromal Corneal Dissection in Refractive Surgery. Transl Vis Sci Technol 2020; 9:22. [PMID: 33024615 PMCID: PMC7521178 DOI: 10.1167/tvst.9.10.22] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/20/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose We introduce a novel focus shaping concept for intrastromal corneal dissection that facilitates cleavage along corneal lamellae, and we analyze laser-tissue interactions governing cutting effectiveness and mechanical side effects. Methods Focus shaping was achieved by a spiral phase plate that converts an incident Gaussian beam into a Laguerre-Gaussian beam with a helical phase. Such vortex beams have zero intensity at their center, are propagation invariant, and possess a ring focus equal in length to the Gaussian focus but with a larger diameter. Cutting precision and the required absorbed energy for flap dissection were compared for Gaussian and vortex beams on ex vivo porcine corneal specimens at pulse durations between 480 fs and 9 ps. Cutting quality and bubble formation were characterized by scanning electron microscopy and macro photography. Results With the vortex beam, the cuts were much smoother. Bubble formation was markedly reduced because cutting can be performed close to the bubble threshold, whereas with the Gaussian beam energies well above threshold are needed. Although the incident energy at the flap dissection threshold was slightly larger for the vortex beam, the absorbed energy was much smaller and contributed more effectively to cutting. This reduced plasma-induced pressure more than sevenfold. Conclusions The vortex beam approach for corneal dissection is a simple, versatile, and cost-effective way of improving the precision of refractive surgery while reducing bubble formation and pressure-related mechanical side effects. Translational Relevance Phase plates for propagation invariant vortex beams are easily implemented in the beam path of next-generation clinical devices.
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Affiliation(s)
| | - Alfred Vogel
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Norbert Linz
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
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Wu D, Li B, Huang M, Fang X. Influence of Cap Thickness on Opaque Bubble Layer Formation in SMILE: 110 Versus 140 µm. J Refract Surg 2020; 36:592-596. [PMID: 32901826 DOI: 10.3928/1081597x-20200720-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/24/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the impact of cap thickness on the formation of an opaque bubble layer (OBL) during small incision lenticule extraction procedures. METHODS In total, 100 eyes from 50 patients were prospectively examined. One of two corneal cap thicknesses was randomly assigned to each eye and differed in the contralateral eye: 110 µm in one eye and 140 µm in the other. OBL area and density were quantitatively assessed. RESULTS The proportion of OBL areas in the anterior lenticule plane was 11.70% ± 7.35% in the 110-µm group, which was significantly higher than the 140-µm group (6.64% ± 4.68%, P < .001). For OBL areas located in the posterior lenticule plane, mean areas for the 110-µm group were also higher than those for the 140-µm group (1.32% ± 1.20% and 0.94% ± 0.59%, respectively; P = .002). Mean gray values of the OBL in the posterior lenticule plane were slightly different between the two groups (P < .001), but no significant difference in OBL of the anterior lenticule plane was observed (P = .055). Eyes with a 110-µm cap thickness had more focal OBLs, revealed by cap scanning (chi-square = 10.256, P = .001). CONCLUSIONS Corneal cap thickness is predictive of opaque bubble layer during small incision lenticule extraction procedures. [J Refract Surg. 2020;36(9):592-596.].
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Development of low laser energy levels in small-incision lenticule extraction: clinical results, black area, and ultrastructural evaluation. J Cataract Refract Surg 2020; 46:410-418. [PMID: 32050215 DOI: 10.1097/j.jcrs.0000000000000071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the outcomes of 4 low laser energy levels after small-incision lenticule extraction (SMILE) surgery. SETTING Zhongshan Ophthalmic Center, Guangzhou, China. DESIGN Prospective randomized clinical trial. METHODS This study evaluated consecutive patients who had SMILE to correct myopia or myopia with astigmatism. Eyes were placed into groups based on the laser energy used during surgery (ie, 105 nJ, 110 nJ, 115 nJ, or 120 nJ). All patients had a thorough ophthalmic examination preoperative and at 4 timepoints over 3 months postoperatively. Black areas and surface regularity of the extracted lenticules were observed and evaluated qualitatively and quantitatively. RESULTS The study comprised 124 eyes of 62 patients (40 women, 22 men), with 31 eyes in each laser energy group. The incidence of black areas was 45.16% (14 of 31 eyes), 12.90% (4 of 31 eyes), 16.13% (5 of 31 eyes), and 12.90% (4 of 31 eyes) for 105 nJ, 110 nJ, 115 nJ, and 120 nJ, respectively. The mean time for lenticule creation was the longest in the 105 nJ group (P = .015). The greatest increase in corneal thickness postoperatively occurred with 105 nJ (P < .05). Regression was highest in the 105 nJ group at 3 months (P < .01). However, corneal horizontal coma (C8) was lowest in the 105 nJ group at 1 week (P = .032). The lenticular surface in the 110 nJ group was the smoothest (P = .011). All contrast sensitivity values varied with time and recovered to preoperative levels by 1 week or 1 month. In all eyes, the uncorrected distance visual acuity and corrected distance visual acuity were good, with no statistically significant differences between the 4 energy groups. CONCLUSIONS The 105 nJ group, in which the lowest energy was used, had the highest risk for black areas, serious postoperative corneal edema, and a significant healing response.
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Changes in corneal biomechanics during small-incision lenticule extraction (SMILE) and femtosecond-assisted laser in situ keratomileusis (FS-LASIK). Lasers Med Sci 2019; 35:599-609. [DOI: 10.1007/s10103-019-02854-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
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Wei CH, Dai QY, Mei LX, Ge Y, Zhang PF, Song E. Paired eye-control study of unilateral opaque bubble layer in femtosecond laser assisted laser in situ keratomileusis. Int J Ophthalmol 2019; 12:654-659. [PMID: 31024822 DOI: 10.18240/ijo.2019.04.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 10/19/2018] [Indexed: 11/23/2022] Open
Abstract
AIM To investigate the predictive factors of the opaque bubble layer (OBL) compared to the fellow eye of same patients in FS200 femtosecond laser assisted laser in situ keratomileusis (FS-LASIK). METHODS This study consisted of 60 consecutive patients (120 eyes) with unilateral OBL during FS-LASIK. Eyes were divided into OBL (the OBL eyes) and OBL-free groups (the fellow eyes) based on the occurrence of OBL. The preoperative demographic data, refraction, keratometry, corneal astigmatism, pachymetry, intraocular pressure and intraoperative data including the outlet location of gas diffusing canal were collected. Conditional logistic regression analysis was performed to find the associated factors with OBL in the two groups by determining odds ratios (OR) and 95%CI. RESULTS The preoperative demographic data, mean spherical errors, mean K value, suction time, intraocular pressure and central cornea thickness were not significantly different between the two groups. The outlet location of gas diffusing canal (P<0.01, OR 7.16, 95%CI 2.53-20.32) and the corneal astigmatism (P=0.013, OR 0.13, 95%CI 0.03-0.65) were significantly associated with the incidence of OBL by multivariate logistic regression analysis. Visual acuity, efficacy, and safety were comparable between the two groups two months after surgery except for a slightly lower predictability value for the hard OBL eyes. CONCLUSION The reduction of the incidence of OBL is obvious when the outlet of gas diffusing canal located at the posterior border of the corneoscleral limbus. This is probably consequent to more effectiveness of gas diffusing canal. Corneal astigmatism is also an independent protective factor for OBL formation.
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Affiliation(s)
- Cheng-Hua Wei
- Department of Ophthalmology, the Second Affiliated Hospital of Soochow University, Suzhou 215004, Jiangsu Province, China.,Department of Ophthalmology, the First Affiliated Hospital of Wannan Medical College, Wuhu 241000, Anhui Province, China
| | - Qiao-Yun Dai
- Department of Ophthalmology, the First Affiliated Hospital of Wannan Medical College, Wuhu 241000, Anhui Province, China
| | - Li-Xin Mei
- Department of Ophthalmology, the First Affiliated Hospital of Wannan Medical College, Wuhu 241000, Anhui Province, China
| | - Yao Ge
- Department of Ophthalmology, the First Affiliated Hospital of Wannan Medical College, Wuhu 241000, Anhui Province, China
| | - Peng-Fei Zhang
- Department of Ophthalmology, the First Affiliated Hospital of Wannan Medical College, Wuhu 241000, Anhui Province, China
| | - E Song
- Department of Ophthalmology, Lixiang Eye Hospital of Soochow University, Suzhou 215021, Jiangsu Province, China
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Damgaard IB, Riau AK, Liu YC, Tey ML, Yam GHF, Mehta JS. Reshaping and Customization of SMILE-Derived Biological Lenticules for Intrastromal Implantation. Invest Ophthalmol Vis Sci 2019; 59:2555-2563. [PMID: 29847663 DOI: 10.1167/iovs.17-23427] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the feasibility of excimer laser reshaping of biological lenticules available after small incision lenticule extraction (SMILE). Methods Fresh and cryopreserved SMILE-derived human lenticules underwent excimer laser ablation for stromal reshaping. The treatment effects in the lasered group were compared with the nonlasered group with respect to changes in surface functional groups (by Fourier transform infrared spectroscopy [FTIR]) and surface morphology (by scanning electron microscopy [SEM] and atomic force microscopy [AFM]). Ten SMILE-derived porcine lenticules, five nonlasered (107-μm thick, -6 diopter [D] spherical power) and five excimer lasered (50% thickness reduction), were implanted into a 120-μm stromal pocket of 10 porcine eyes. Corneal thickness and topography were assessed before and after implantation. Results FTIR illustrated prominent changes in the lipid profile. The collagen structure was also affected by the laser treatment but to a lesser extent. SEM exhibited a more regular surface for the lasered lenticules, confirmed by the lower mean Rz value (290.1 ± 96.1 nm vs. 380.9 ± 92.6 nm, P = 0.045) on AFM. The lasered porcine lenticules were thinner than the nonlasered controls during overhydration (132 ± 26 μm vs. 233 ± 23 μm, P < 0.001) and after 5 hours in a moist chamber (46 ± 3 μm vs. 57 ± 3 μm, P < 0.001). After implantation, the nonlasered group showed a tendency toward a greater increase in axial keratometry (6.63 ± 2.17 D vs. 5.60 ± 3.79 D, P = 0.613) and elevation (18.6 ± 15.4 vs. 15.2 ± 5.5, P = 0.656) than the lasered group. Conclusions Excimer laser ablation may be feasible for thinning and reshaping of SMILE-derived lenticules before reimplantation or allogenic transplantation. However, controlled lenticule dehydration before ablation is necessary in order to allow stromal thinning.
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Affiliation(s)
- Iben Bach Damgaard
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark.,Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Andri Kartasasmita Riau
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Yu-Chi Liu
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Singapore National Eye Centre, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Graduate Medical School, Singapore
| | - Min Li Tey
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gary Hin-Fai Yam
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Graduate Medical School, Singapore
| | - Jodhbir Singh Mehta
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,School of Materials Science and Engineering, Nanyang Technological University, Singapore.,Singapore National Eye Centre, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Graduate Medical School, Singapore
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Enhancement of refractive outcomes of small-incision lenticule extraction via tear-film control. Graefes Arch Clin Exp Ophthalmol 2018; 256:2259-2268. [PMID: 30056550 DOI: 10.1007/s00417-018-4074-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/16/2018] [Indexed: 10/28/2022] Open
Abstract
PURPOSE To suggest that tear film is a refractive outcome predictor in small-incision lenticule extraction (SMILE) for myopia and describe methods of controlling the tear film and its effects on refractive outcomes. METHODS In this retrospective case-control study, the tear film was kept clear and appropriate in amount during tear-film-controlled SMILE (TFC-SMILE). In contrast, no special care to the tear film was given in direct-docking SMILE (DD-SMILE). Both procedures were performed by the same experienced surgeon, using the same surgical parameters, over defined periods. In select cases, scanning electron microscopy (SEM) of the lenticule and surgical videos of opaque bubble layers (OBLs) were obtained and compared. RESULTS Forty-one eyes had DD-SMILE and 55 eyes had TFC-SMILE. Multivariate analysis showed that TFC-SMILE and the patient's age were significant predictors of refractive outcomes. The refractive predictability of TFC-SMILE was better than that of DD-SMILE, and under-correction of high myopia was evident in the latter patients. The predictive errors of DD-SMILE became more myopic and variable during 1 year than those of TFC-SMILE. The lenticular surface on SEM was more serrated in DD-SMILE. Severe OBLs were evident in four cases of DD-SMILE and the OBL pattern was sporadic at the anterior surface of the lenticule. CONCLUSIONS The presence of a clear and appropriate tear film in SMILE enhanced predictability, minimized variability, and ensured stability of refractive outcomes. An uncontrolled tear film might render cutting imprecise and trigger severe OBL formation. TFC-SMILE had more predictable results than DD-SMILE.
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Abstract
PURPOSE To describe the intraoperative complications observed during the initial learning curve of small incision lenticule extraction (SMILE) and their management. METHODS Prospective evaluation of 100 consecutive eyes (50 patients) undergoing SMILE was performed at an apex tertiary care ophthalmic center. Patients older than 18 years with a stable refractive error ranging from -1.0 to -10.0 D myopia and up to 3.0 D astigmatism were included. Any intraoperative complications and their management were noted. Postoperative examination including visual acuity was performed on day 1, 1 week, and 1 month. RESULTS Intraoperative difficulties observed in the initial 100 eyes included suction loss (2%), black spots (11%), opaque bubble layer (19%), epithelial defect (2%), and difficult lenticule extraction (9%). Difficult lenticule dissection and extraction was the most surgically challenging step and resulted in posterior stromal damage, anterior cap tear (1%), side-cut tears (4%), partially retained lenticule (1%), and completely retained lenticule (2%). Its incidence decreased from 16% (8/50) in the initial 50 cases to 2% (1/50) in the next 50 cases. Two eyes with completely retained lenticule were re-treated with flap-based excimer laser ablation after 3 months. Optimal visual and anatomical outcomes could be achieved, and no sight-threatening complication was observed in any case. CONCLUSIONS The learning curve of SMILE is surgically challenging. Lenticule dissection and extraction is the most difficult step and leads to a multitude of complications. Most complications that result in delayed visual recovery are observed in the initial 50 cases.
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Li L, Schallhorn JM, Ma J, Zhang L, Dou R, Wang Y. Risk Factors for Opaque Bubble Layer in Small Incision Lenticule Extraction (SMILE). J Refract Surg 2017; 33:759-764. [DOI: 10.3928/1081597x-20170821-02] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/07/2017] [Indexed: 11/20/2022]
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Wu N, Christenbury JG, Dishler JG, Bozkurt TK, Duel D, Zhang L, Hamilton DR. A Technique to Reduce Incidence of Opaque Bubble Layer Formation During LASIK Flap Creation Using the VisuMax Femtosecond Laser. J Refract Surg 2017; 33:584-590. [DOI: 10.3928/1081597x-20170621-06] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 06/07/2017] [Indexed: 11/20/2022]
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Ma J, Wang Y, Li L, Zhang J. Corneal thickness, residual stromal thickness, and its effect on opaque bubble layer in small-incision lenticule extraction. Int Ophthalmol 2017; 38:2013-2020. [DOI: 10.1007/s10792-017-0692-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 08/07/2017] [Indexed: 11/24/2022]
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Ji YW, Kim M, Kang DSY, Reinstein DZ, Archer TJ, Choi JY, Kim EK, Lee HK, Seo KY, Kim TI. Lower Laser Energy Levels Lead to Better Visual Recovery After Small-Incision Lenticule Extraction: Prospective Randomized Clinical Trial. Am J Ophthalmol 2017; 179:159-170. [PMID: 28499707 DOI: 10.1016/j.ajo.2017.05.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 04/27/2017] [Accepted: 05/01/2017] [Indexed: 11/24/2022]
Abstract
PURPOSE To determine the effect of lowering laser energy on clinical outcomes in small-incision lenticule extraction (SMILE). DESIGN Prospective randomized clinical trial. METHODS A total of 151 patients (151 eyes) with moderate myopia scheduled for SMILE were included: 58 eyes received SMILE with low energy (100, 105, and 110 nJ; L-SMILE group) and 93 with conventional energy (115-150 nJ; C-SMILE group). Patients received complete ophthalmic examinations preoperatively and over 3 months postoperatively. RESULTS Uncorrected distance visual acuity (logMAR UDVA) 1 day and 1 week postoperatively was significantly better in L-SMILE than in C-SMILE (P < .001 and P = .005, respectively). There was no significant difference between the groups at 1 and 3 months. L-SMILE induced significantly fewer corneal aberrations compared with C-SMILE at 1 week and 1 month postoperatively (both P < .01), but there were no significant differences at 3 months. Though there was no difference in logMAR UDVA over the postoperative period between the 100, 105, and 110 nJ subgroups, there was a significant difference in logMAR UDVA on postoperative day 1 between L-SMILE and each subgroup in which an energy level of 115 nJ or higher was used. Furthermore, logMAR UDVA on postoperative day 1 showed a significant correlation with laser energy (r = 0.451, P < .001) and multiple linear regression analysis revealed that energy level was the only independent factor associated with logMAR UDVA on postoperative day 1 (P < .001). CONCLUSIONS SMILE using femtosecond energy of less than 115 nJ facilitates better visual acuity with less induction of corneal aberrations in the early postoperative period.
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