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Teo ZL, Ang M. Femtosecond laser-assisted in situ keratomileusis versus small-incision lenticule extraction: current approach based on evidence. Curr Opin Ophthalmol 2024; 35:278-283. [PMID: 38700941 DOI: 10.1097/icu.0000000000001060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
PURPOSE OF REVIEW Laser keratorefractive surgery achieves excellent visual outcomes for refractive error correction. With femtosecond laser, small incision lenticule extraction (SMILE) is an increasingly viable alternative to laser-assisted in situ keratomileusis (LASIK). Comparative studies demonstrate similar efficacy and predictability between SMILE and LASIK, making it difficult for clinicians to choose which to use. This review thus compares femtosecond-LASIK (FS-LASK) and SMILE in various scenarios, to assist clinicians in deciding which refractive surgery procedure to recommend. RECENT FINDINGS SMILE may be superior for highly myopic eyes due to a smaller decrease in functional optical zone. SMILE further induces less spherical aberration and less overall higher order aberrations in mesopic conditions. SMIILE also has less postoperative dry eye, making it suitable those with preexisting dry eye. For low to moderate myopic astigmatism correction, FS-LASIK has less undercorrection compared to SMILE. Lastly, SMILE has not yet received Food and Drug Administration or Conformité Européenne approval for hyperopic correction, rendering FS-LASIK the choice of procedure for hyperopic correction. SUMMARY Both FS-LASIK and SMILE demonstrate good efficacy and predictability. Understanding specific clinical scenarios where one may be superior to the other will aid clinicians in choosing the most suitable procedure for personalized care.
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Affiliation(s)
- Zhen Ling Teo
- Singapore National Eye Centre, Singapore Eye Research Institute
| | - Marcus Ang
- Singapore National Eye Centre, Singapore Eye Research Institute
- Department of Cornea and External Eye Disease, Refractive Surgery, Singapore National Eye Centre
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
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2
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Lin SH, Fang YH, Jia FL, Li YJ. Neurogenic dry eye associated with intravitreal injection of anti-VEGF agents. Eur J Ophthalmol 2024; 34:NP35-NP40. [PMID: 37350417 DOI: 10.1177/11206721231177475] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
PURPOSE To report a case of neurogenic dry eye (NDE) that developed after intravitreal ranibizumab injection (IVR). CASE REPORT A 71-year-old woman had a history of cataract phacoemulsification and intraocular lens (IOL) implantation, Nd:YAG laser posterior capsulotomy and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Aneurysmal dilatation of the inferior temporal retina was found in the left fundus, which was diagnosed as retinal aneurysm, and intravitreal ranibizumab injection was administered. Dry eye was found in the left eye after the first injection. After the second injection, the patient developed severe dry eye with left eye dryness, photophobia, irritation, and blurred vision. The tear film breakup time (TBUT) value was 3 s, the Schirmer test value was 2 mm/5 min, corneal fluorescein staining (CFS) showed diffuse patellar staining of the corneal epithelium with a staining area of >50% and irregular staining at the edge of the corneal flap, and the corneal touch threshold value in the filament length was 1.5 cm in the left eye. CONCLUSIONS Patients with a history of intraocular lens implantation, Nd:YAG laser posterior capsulotomy, and femtosecond laser-assisted laser in situ keratomileusis surgery may have increased drug permeability due to an increased concentration of anti-VEGF drugs in the aqueous layer and thinning of the stromal layer of the cornea. The corneal subepithelial nerve repair mechanism was destroyed, causing neurogenic dry eye.
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Affiliation(s)
- Shu-Hua Lin
- Department of Ophthalmology, Fuyang People's Hospital of Anhui Medical University, Fuyang, Anhui, China
- Department of Ophthalmology, Affiliated Hospital of Yanbian University, Yanji, Jilin, China
| | - Yu-Hui Fang
- Department of Dermatology, Fuyang People's Hospital of Anhui Medical University, Fuyang, Anhui, China
| | - Fa-Li Jia
- Department of Ophthalmology, Affiliated Hospital of Yanbian University, Yanji, Jilin, China
| | - Ying-Jun Li
- Department of Ophthalmology, Fuyang People's Hospital of Anhui Medical University, Fuyang, Anhui, China
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3
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Lu X, Chen Z, Lu J, Watsky MA. Effects of 1,25-Vitamin D3 and 24,25-Vitamin D3 on Corneal Nerve Regeneration in Diabetic Mice. Biomolecules 2023; 13:1754. [PMID: 38136625 PMCID: PMC10742127 DOI: 10.3390/biom13121754] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/30/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023] Open
Abstract
Corneal nerve homeostasis is essential for the functional integrity of the ocular surface. Vitamin D deficiency (VDD) and vitamin D receptor knockout (VDR KO) have been found to reduce corneal nerve density in diabetic mice. This is the first study to comprehensively examine the influence of vitamin D on nerve regeneration following corneal epithelial injury in diabetic mice. Corneal nerve regeneration was significantly retarded by diabetes, VDR KO, and VDD, and it was accelerated following topical 1,25 Vit D and 24,25 Vit D administration. Furthermore, topical 1,25 Vit D and 24,25 Vit D increased nerve growth factor, glial cell line-derived neurotropic factor, and neurotropin-3 protein expression, and it increased secretion of GDNF protein from human corneal epithelial cells. CD45+ cells and macrophage numbers were significantly decreased, and vitamin D increased CD45+ cell and macrophage recruitment in these wounded diabetic mouse corneas. The accelerated nerve regeneration observed in these corneas following topical 1,25 Vit D and 24,25 Vit D administration may be related to the vitamin D-stimulated expression, secretion of neurotrophic factors, and recruitment of immune cells.
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Affiliation(s)
- Xiaowen Lu
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1120 15th Street, CB-2901, Augusta, GA 30912, USA
| | | | | | - Mitchell A. Watsky
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1120 15th Street, CB-2901, Augusta, GA 30912, USA
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4
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Gomes JAP, Azar DT, Baudouin C, Bitton E, Chen W, Hafezi F, Hamrah P, Hogg RE, Horwath-Winter J, Kontadakis GA, Mehta JS, Messmer EM, Perez VL, Zadok D, Willcox MDP. TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface. Ocul Surf 2023; 29:331-385. [PMID: 37087043 DOI: 10.1016/j.jtos.2023.04.011] [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: 04/07/2023] [Accepted: 04/10/2023] [Indexed: 04/24/2023]
Abstract
The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.
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Affiliation(s)
- José Alvaro P Gomes
- Dept. of Ophthalmology and Visual Sciences, Federal University of Sao Paulo/Paulista School of Medicine (UNIFESP/EPM), Sao Paulo, SP, Brazil.
| | - Dimitri T Azar
- University of Illinois College of Medicine, Chicago, IL, USA
| | - Christophe Baudouin
- Quinze-Vingts National Eye Hospital & Vision Institute, IHU FOReSIGHT, Paris, France
| | - Etty Bitton
- Ecole d'optométrie, Université de Montréal, Montréal, Canada
| | - Wei Chen
- Eye Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | | | - Pedram Hamrah
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Ruth E Hogg
- Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Belfast, UK
| | | | | | | | | | - Victor L Perez
- Foster Center for Ocular Immunology, Duke University Eye Center, Durham, NC, USA
| | - David Zadok
- Shaare Zedek Medical Center, Affiliated to the Hebrew University, School of Medicine, Jerusalem, Israel
| | - Mark D P Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Liu M, Jin C, Lu L, Yuan Y, Chen C, Zhao T, Ke B. The Impact of Corneal Epithelial Thickening and Inhomogeneity on Corneal Aberrations After Small Incision Lenticule Extraction. J Refract Surg 2023; 39:23-32. [PMID: 36630428 DOI: 10.3928/1081597x-20221109-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE To investigate the corneal epithelial remodeling profile after small incision lenticule extraction (SMILE), the correlated explanatory variables, and its potential impact on corneal higher order aberrations (HOAs). METHODS This single-center study prospectively evaluated 75 right eyes of 75 patients scheduled for SMILE. An anterior segment optical coherence tomography device was used to automatically obtain central 6-mm corneal epithelial thickness (ET), total corneal HOAs, and individual Zernike components before and after surgery. The ET inhomogeneity over the central 3- and 6-mm cornea was quantified with coefficient of variance (CV). RESULTS Both ET and CV significantly increased 1 month postoperatively (all P < .05). The stepwise multiple regression analysis showed that ET and CV were significantly correlated with preoperative ET and CV, respectively (all P < .01). The corrected spherical equivalent also significantly influenced ET and CV (all P < .01). Over the central 6-mm zone, the alterations of total corneal HOAs and individual Zernike components such as vertical coma (Z7) and spherical aberration (Z12, Z24) were significantly correlated with ET and CV (all P < .05). CONCLUSIONS The SMILE-induced epithelial remodeling involved both ET and ET inhomogeneity. The modulation was associated with preoperative and treatment parameters, and exerted a significant impact on corneal HOA alterations especially over the central 6-mm cornea. Together with the amount of correction and corneal curvature gradient change, preoperative assessment of ET and ET inhomogeneity might help predict postoperative epithelial remodeling. [J Refract Surg. 2023;39(1):23-32.].
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Reinstein DZ, Carp GI, Archer TJ, Vida RS, Yammouni R. Large Population Outcomes of Small Incision Lenticule Extraction in Young Myopic Patients. J Refract Surg 2022; 38:488-496. [PMID: 35947004 DOI: 10.3928/1081597x-20220623-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the outcomes of small incision lenticule extraction (SMILE) for myopia in a large population of young adults. METHODS In this retrospective case series, the patient population consisted of the first 4,138 consecutive SMILE treatments using the VisuMax femtosecond laser (Carl Zeiss Meditec) between 2012 and 2018 at the London Vision Clinic. Inclusion criteria were myopic spherical equivalent up to -9.00 diopters (D), cylinder up to 6.00 D, corrected distance visual acuity of 20/20 or better, age younger than 40 years, and follow-up of 12 months. Outcomes analysis was performed using the Standard Graphs for Reporting Refractive Surgery. RESULTS Data were available at 12 months in 3,722 eyes (90%), and 416 eyes (10%) were lost to follow-up. Mean attempted spherical equivalent refraction (SEQ) was -4.61 ± 1.84 D (range: -1.12 to -9.00 D). Mean cylinder was -0.78 ± 0.66 D (range: 0.00 to -6.00 D). Postoperatively, the mean SEQ relative to target was -0.13 ± 0.30 D (range: -1.35 to +1.25 D) and was within ±0.50 D in 88.1% and ±1.00 D in 99.6% of eyes. Uncorrected distance visual acuity was 20/20 or better in 95.4% of eyes and 20/25 or better in 98.7% of eyes. One line of CDVA was lost in 3.0% of eyes, and 0.08% (n = 3) lost two or more lines of CDVA, for which CDVA was restored following phototherapeutic keratectomy treatment. There was a statistically significant improvement of 0.05, 0.06, 0.07, and 0.07 log units for contrast sensitivity at 3, 6, 12, and 18 cycles per degree, respectively (P < .001). CONCLUSIONS SMILE achieved excellent outcomes for myopia up to -9.00 D with cylinder up to -5.50 D for a large population in patients without presbyopia. [J Refract Surg. 2022;38(8):488-496.].
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7
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Corneal Sensitivity and Patient-Reported Dry Eye Symptoms in a Prospective Randomized Contralateral-Eye Trial Comparing LASIK and SMILE. Am J Ophthalmol 2022; 241:248-253. [PMID: 35594919 DOI: 10.1016/j.ajo.2022.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/28/2022] [Accepted: 05/13/2022] [Indexed: 11/23/2022]
Abstract
PURPOSE To prospectively compare corneal sensation and patient-reported symptoms of dry eye in individuals undergoing laser-assisted in situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE). DESIGN Prospective randomized contralateral-eye clinical trial. METHODS 80 eyes of 40 patients with myopia at Byers Eye Institute at Stanford University were randomized to receive wavefront-guided femtosecond LASIK in one eye and SMILE in the fellow eye. Cochet-Bonnet esthesiometry was performed to assess corneal sensitivity preoperatively and at the 1-month, 3-month, 6-month, and 12-month postoperative visits. Participants also completed questionnaires at each visit to determine the Ocular Surface Disease Index (OSDI). RESULTS Eyes that underwent LASIK compared to SMILE demonstrated more cornea denervation at the postoperative 1-month (mean 2.1 vs 3.6 cm, p < 0.001), 3-month (3.5 vs 5.4 cm, p < 0.001) and 6-month (4.7 vs 5.7 cm, p < 0.001) visits. At the 12-month visit, both groups had returned to baseline corneal sensitivity (5.9 vs 5.9 cm, p = 0.908). There was no difference in OSDI between the two groups at any visit. Mean OSDI improved from the preoperative to the postoperative 12-month visit in both LASIK (15.3 to 8.6, p = 0.020) and SMILE (15.1 to 9.5, p = 0.029) groups. CONCLUSIONS LASIK resulted in greater corneal denervation compared to SMILE in the early postoperative period, though this difference was no longer apparent after 12 months. Despite this, there was no difference in self-reported dry eye symptoms between the two groups. Patient-reported dry eye symptoms improved after both LASIK and SMILE procedures.
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8
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Fuest M, Mehta JS. Advances in refractive corneal lenticule extraction. Taiwan J Ophthalmol 2021; 11:113-121. [PMID: 34295616 PMCID: PMC8259523 DOI: 10.4103/tjo.tjo_12_21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 03/16/2021] [Indexed: 01/31/2023] Open
Abstract
Refractive errors are the leading cause of reversible visual impairment worldwide. In addition to the desired spectacle independence, refractive procedures can improve quality of life, working ability, and daily working performance. Refractive corneal lenticule extraction (RCLE) is a relatively new technique, dependent only on a femtosecond laser (FS). This leads to potential benefits over laser-assisted in situ keratomileusis (LASIK) including a quicker recovery of dry eye disease, a larger functional optical zone, and no flap-related complications. SMILE, available with the VisuMax FS (Carl Zeiss Meditec AG, Jena, Germany), is the most established RCLE application, offering visual and refractive outcomes comparable to LASIK. SmartSight (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany) and CLEAR (Ziemer Ophthalmic Systems AG, Port, Switzerland) are two new RCLE applications that received Conformité Européenne (CE) approval in 2020. In this article, we review refractive and visual outcomes, advantages, and disadvantages of RCLE and also report on the latest advances in RCLE systems.
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Affiliation(s)
- Matthias Fuest
- Department of Ophthalmology, RWTH Aachen University, Aachen, Germany
| | - Jodhbir S Mehta
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Singapore National Eye Centre, Singapore.,Eye-Academic Clinical Program, Duke-National University of Singapore Graduate Medical School, Singapore.,School of Material Science and Engineering, Nanyang Technological University, Singapore
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9
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Sioufi K, Zheleznyak L, MacRae S, Rocha KM. Femtosecond Lasers in Cornea & Refractive Surgery. Exp Eye Res 2021; 205:108477. [PMID: 33516763 DOI: 10.1016/j.exer.2021.108477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 11/18/2022]
Abstract
Since the introduction of femtosecond laser (FS) systems for corneal flap creation in laser-assisted in-situ keratomileusis there have been numerous applications for FS laser in corneal surgery. This manuscript details the utility of FS lasers in corneal surgical procedures including refractive laser surgeries, intracorneal ring segment tunnels, presbyopic treatments, and FS-assisted keratoplasty. We also review the role of FS lasers in diagnostic procedures such as two photon excitation fluorescence and second harmonic generation.
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Affiliation(s)
- Kareem Sioufi
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | | | - Scott MacRae
- Flaum Eye Institute and the Institute of Optics, University of Rochester, Rochester, NY, USA
| | - Karolinne M Rocha
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA.
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10
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Gong Q, Zhang S, Jiang L, Lin M, Xu Z, Yu Y, Wang Q, Lu F, Hu L. The effect of nerve growth factor on corneal nerve regeneration and dry eye after LASIK. Exp Eye Res 2021; 203:108428. [PMID: 33400926 DOI: 10.1016/j.exer.2020.108428] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 12/15/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
Dry eye is the most common complication after refractive surgery, especially after laser in situ keratomileusis (LASIK), in which nerves may be cut when making the corneal flap. Nerve growth factor (NGF) has been demonstrated to stimulate corneal sensitivity and nerve regeneration and NGF has been suggested as a potential treatment for dry eye disease (DED). Hence, this study aimed to investigate the effect of NGF on corneal nerve regeneration, sensitivity and dry eye symptoms after LASIK, compared to hycosan and normal saline (NS) treatments. Thirty-eight New Zealand white rabbits that underwent LASIK procedures were randomly assigned to three groups. Each group underwent NGF, hycosan, and NS treatment. The nerve densities and the number of corneal sub-basal and superficial stromal nerves were measured with confocal microscopy, and the results were compared before surgery and at one month and three months postoperatively. Corneal sensitivity was assessed with an esthesiometer. The tear breakup time (TBUT) was recorded to check for signs of dry eye. The whole corneas of the experimental animals were excised at three months after the surgery for immunohistochemically analysis. After LASIK, treatment with NGF significantly accelerated the recovery of sub-basal and superficial stromal nerve densities and the numbers, compared to hycosan and NS treatments at one month and three months postoperatively (NGF vs. hycosan, P < 0.01 each; NGF vs. NS, P < 0.01 each). The recovery of corneal sensitivity was significantly enhanced in the NGF group compared to the hycosan or NS treatment groups after surgery (P < 0.05). Also, the TBUT data showed a statistically significant longer time in the NGF group at one month, and three months postoperatively (P < 0.05). Immunofluorescence analysis showed the nerve fiber quantity of the NGF group was larger than in the hycosan and NS groups. Taken together, the experimental results suggested that mNGF had an obvious effect on promoting corneal nerve repairing and the potential to improve dry eye in different periods following LASIK.
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Affiliation(s)
- Qianwen Gong
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Shasha Zhang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Ophthalmology, The Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, Shanxi, China
| | - Lu Jiang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Hankou Aier Eye Hospital, Wuhan, Hubei, China
| | - Meng Lin
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhiqiang Xu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ye Yu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qinmei Wang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Fan Lu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
| | - Liang Hu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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11
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Medeiros CS, Santhiago MR. Corneal nerves anatomy, function, injury and regeneration. Exp Eye Res 2020; 200:108243. [PMID: 32926895 DOI: 10.1016/j.exer.2020.108243] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 12/29/2022]
Abstract
The cornea is a highly innervated tissue, exhibiting a complex nerve architecture, distribution, and structural organization. Significant contributions over the years have allowed us to come to the current understanding about the corneal nerves. Mechanical or chemical trauma, infections, surgical wounds, ocular or systemic comorbidities, can induce corneal neuroplastic changes. Consequently, a cascade of events involving the corneal wound healing, trophic functions, neural circuits, and the lacrimal products may interfere in the corneal homeostasis. Nerve physiology drew the attention of investigators due to the popularization of modern laser refractive surgery and the perception of the destructive potential of the excimer laser to the corneal nerve population. Nerve fiber loss can lead to symptoms that may impact the patient's quality of life, and impair the best-corrected vision, leading to patient and physician dissatisfaction. Therefore, there is a need to better understand preoperative signs of corneal nerve dysfunction, the postoperative mechanisms of nerve degeneration and recovery, aiming to achieve the most efficient way of treating nerve disorders related to diseases and refractive surgery.
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Affiliation(s)
| | - Marcony R Santhiago
- University of São Paulo, São Paulo, SP, Brazil; University of Southern California, Los Angeles, CA, United States
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12
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Ahmed AA, Hatch KM. Advantages of Small Incision Lenticule Extraction (SMILE) for Mass Eye and Ear Special Issue. Semin Ophthalmol 2020; 35:224-231. [PMID: 32892680 DOI: 10.1080/08820538.2020.1807028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This review summarizes the advantages of Small-incision lenticule extraction (SMILE), including improved patient intraoperative experience, improved postoperative ocular surface, low incidence of regression, low re-treatment rates, and advantageous biomechanical corneal stability. Visual and refractive outcomes are similar to those achieved with LASIK, notably in large population studies. Since the inception of SMILE almost 10 years ago, the procedure has been rapidly growing in popularity. With the implementation of the novel SMILE technology in their practice, refractive surgeons generate excitement and potential for expanding the refractive market. Other parts of the world, including Asia, Europe, and Russia, SMILE has become the most popular refractive procedure performed. It is speculated that as SMILE continues to grow in popularity in the US since FDA approval in 2016 and more refractive surgeons implement this technology into their practice, it will drive an increase in the refractive market similar to what is seen in other countries.
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Affiliation(s)
- Amani A Ahmed
- Anterior Segment - Cornea and Refractive Surgery, Mass Eye and Ear Main Campus , Boston, MA, USA.,Anterior Segment - Cornea and Refractive Surgery, Harvard University , Boston, MA, USA
| | - Kathryn M Hatch
- Anterior Segment - Cornea and Refractive Surgery, Mass Eye and Ear Main Campus , Boston, MA, USA.,Anterior Segment - Cornea and Refractive Surgery, Harvard University , Boston, MA, USA
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13
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Ang M, Gatinel D, Reinstein DZ, Mertens E, Alió Del Barrio JL, Alió JL. Refractive surgery beyond 2020. Eye (Lond) 2020; 35:362-382. [PMID: 32709958 DOI: 10.1038/s41433-020-1096-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/19/2020] [Accepted: 07/08/2020] [Indexed: 02/07/2023] Open
Abstract
Refractive surgery refers to any procedure that corrects or minimizes refractive errors. Today, refractive surgery has evolved beyond the traditional laser refractive surgery, embodied by the popular laser in situ keratomileusis or 'LASIK'. New keratorefractive techniques such as small incision lenticule extraction (SMILE) avoids corneal flap creation and uses a single laser device, while advances in surface ablation techniques have seen a resurgence in its popularity. Presbyopic treatment options have also expanded to include new ablation profiles, intracorneal implants, and phakic intraocular implants. With the improved safety and efficacy of refractive lens exchange, a wider variety of intraocular lens implants with advanced optics provide more options for refractive correction in carefully selected patients. In this review, we also discuss possible developments in refractive surgery beyond 2020, such as preoperative evaluation of refractive patients using machine learning and artificial intelligence, potential use of stromal lenticules harvested from SMILE for presbyopic treatments, and various advances in intraocular lens implants that may provide a closer to 'physiological correction' of refractive errors.
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Affiliation(s)
- Marcus Ang
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore. .,Department of Ophthalmology and Visual Science, Duke-NUS Graduate Medical School, Singapore, Singapore.
| | | | - Dan Z Reinstein
- London Vision Clinic, London, UK.,Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Sorbonne Université, Paris, France.,Biomedical Science Research Institute, Ulster University, Belfast, UK
| | - Erik Mertens
- Medipolis-Antwerp Private Clinic, Antwerp, Belgium
| | - Jorge L Alió Del Barrio
- Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain.,Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
| | - Jorge L Alió
- Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain.,Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
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14
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Liu L, Cheng W, Wu D, Chen L, Yu S, Zuo T, Zhang L, Yang K, Li H, Zhang H, Wei P, Ng ALK, Cheng GPM, Woo VCP, Yin J, Chiu K, Wang Y. The Differential Expression of Cytokines and Growth Factors After SMILE Compared With FS-LASIK in Rabbits. Invest Ophthalmol Vis Sci 2020; 61:55. [PMID: 32460319 PMCID: PMC7405797 DOI: 10.1167/iovs.61.5.55] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the differential expression of cytokines and growth factors in the cornea and aqueous humor after small incision lenticule extraction (SMILE) compared with femtosecond LASIK (FS-LASIK) using rabbit model. Methods Sixteen eyes of 16 rabbits in each group underwent SMILE or FS-LASIK with refractive correction of −6.00 DS/−1.00 DC. Eight additional rabbits served as controls. Pre- and 24 hours, 1 week, 1 month, and 3 months postoperatively, slit-lamp and anterior segment optical coherence tomography were performed, followed by cornea and aqueous humor collection. Apoptosis and proliferation were evaluated with TUNEL assay and Ki-67 immunostaining, respectively. The mRNA and protein expression of cytokines and growth factors was determined by RT-qPCR and Western blotting, respectively. Cytokine levels in the aqueous humor were detected with ELISA. Results Compared with FS-LASIK, SMILE induced less apoptosis and proliferation in the cornea within 1 week postoperatively. Levels of IL-1β, TNF-α, and EGFR in the cornea were significantly increased after FS-LASIK compared with SMILE within 24 hours. Levels of IL-8 in the aqueous humor remained elevated until 1 week after FS-LASIK but not SMILE. TGF-β1 level was elevated up to 1 month after both procedures, while BFGF level was kept high within 1 month after SMILE but not FS-LASIK. Conclusions SMILE could induce significantly less acute inflammation than FS-LASIK in the cornea and aqueous humor. The differential expression of TGF-β1 and BFGF between two procedures until 1 month might contribute to the post-SMILE delayed recovery and underline the importance of continued treatment postoperatively.
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Shah R. History and Results; Indications and Contraindications of SMILE Compared With LASIK. Asia Pac J Ophthalmol (Phila) 2019; 8:371-376. [PMID: 31567264 PMCID: PMC6784775 DOI: 10.1097/01.apo.0000580132.98159.fa] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/30/2019] [Indexed: 11/26/2022] Open
Abstract
Small incision lenticule extraction (SMILE) is a new paradigm for refractive surgery, and was first performed by Sekundo and Blum in 2008. It uses only a femtosecond laser to carve out a lenticule within the corneal stroma, and then achieves refractive correction by extracting the lenticule through a small incision. A number of studies have shown that SMILE leads to stable and efficacious outcomes, combined with high safety. Long-term studies also indicate that SMILE has excellent outcomes combined with high safety. Although relatively safe, SMILE can have some intraoperative and postoperative complications, including suction loss during the procedure, lenticule tears, incision tears, epithelial ingrowth, diffuse lamellar keratitis, and residual refractive error. Studies indicate that SMILE leads to less postoperative dry eyes. It is thus preferred over laser-assisted in-situ keratomileusis (LASIK) in cases wherein there is mild dry eye preoperatively. It is also preferred over LASIK in cases wherein the patient is likely to engage in contact sports. LASIK may be preferred over SMILE for the treatment of hyperopia, and in cases of significant higher order wavefront aberrations or topographic irregularities.
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Zhao J, Shang J, Niu L, Xu H, Yang D, Zhao Y, Fu D, Zhou X. Two-year outcome of an eye that underwent hyperopic LASIK following inadvertent myopic SMILE lenticule in situ implantation. BMC Ophthalmol 2019; 19:176. [PMID: 31395052 PMCID: PMC6686401 DOI: 10.1186/s12886-019-1188-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 07/31/2019] [Indexed: 01/09/2023] Open
Abstract
Background This report describes a case in which hyperopic femtosecond laser-assisted in situ keratomileusis (FS-LASIK) was performed following small incision lenticule extraction (SMILE) lenticule in situ implantation. Case presentation The hyperopic left eye of a 46-year-old patient with refraction of + 7.75 diopters sphere (DS)/− 1.25 diopters cylinder (DC) × 5° and corrected distance visual acuity (CDVA) of 20/50 mistakenly underwent the SMILE procedure for myopic astigmatism (− 8.50 DS/− 1.50 DC × 175°) due to medical negligence. The extracted lenticule was subsequently re-implanted in situ. After 8 months, the left eye underwent FS-LASIK to correct hyperopia and astigmatism (+ 5.0 DS/− 0.75 DC × 100°). Two years after FS-LASIK, corneal tomography showed no ectasia and microscopy revealed transparent cornea. The left eye exhibited CDVA of 20/50 with refraction of − 0.75 DS/− 0.25 DC × 165°. Conclusions SMILE lenticule in situ implantation offers a solution for corneal volume and thickness restoration. FS-LASIK provides feasible correction of refractive error following lenticule re-implantation. Future studies are needed for determining the effectiveness of the treatment.
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Affiliation(s)
- Jing Zhao
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Jianmin Shang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Lingling Niu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Haipeng Xu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Dong Yang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Yu Zhao
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Dan Fu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China
| | - Xingtao Zhou
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Key NHC Key Laboratory of Myopia; Laboratory of Myopia, Chinese Academy of Medical Sciences, 83 FenYang Road, Shanghai, 200031, China.
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Reinstein DZ, Carp GI, Archer TJ, Vida RS. Outcomes of Re-treatment by LASIK After SMILE. J Refract Surg 2018; 34:578-588. [PMID: 30199561 DOI: 10.3928/1081597x-20180717-02] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 07/03/2018] [Indexed: 11/20/2022]
Abstract
PURPOSE To report the outcomes of LASIK re-treatments after small incision lenticule extraction (SMILE). METHODS Retrospective review of all eyes to have undergone a re-treatment by LASIK after primary SMILE between September 2013 and January 2016. Thin-flap LASIK was used in most cases as long as sufficient tissue was available for safe flap creation between the maximum epithelial thickness and minimum cap thickness. Otherwise, the SMILE interface was converted into a LASIK flap by the Circle technique or side cut only. The multivariate nomogram for LASIK re-treatments was used, including sphere, cylinder, age, and primary spherical equivalent (SEQ) as variables. Patients were observed for 1 year after surgery and standard outcomes analysis was performed. RESULTS A total of 116 LASIK re-treatments were performed in a population of 2,643 consecutive SMILE procedures, indicating a re-treatment rate of 4.39%. Mean attempted SEQ was -0.05 ± 0.99 diopters (D) (range: -1.88 to +1.50 D). Mean cylinder was -0.70 ± 0.55 D (range: 0.00 to -2.25 D). Postoperative uncorrected distance visual acuity was 20/20 or better in 81% of eyes, for a population with corrected distance visual acuity (CDVA) of 20/20 or better in 95% before re-treatment. Mean postoperative SEQ relative to the target was +0.19 ± 0.49 D (range: -0.88 to +2.13 D), with 74% within ±0.50 D. Mean postoperative cylinder was -0.29 ± 0.24 D (range: 0.00 to -1.25 D). There was one line loss of CDVA in 15% of eyes, but no eyes lost two or more lines. There was a small increase in contrast sensitivity (P < .05). Overcorrection was identified in myopic re-treatments (n = 20) of -1.00 D or more; mean postoperative SEQ was +0.59 ± 0.64 D (range: -0.63 to +2.13 D). CONCLUSIONS Re-treatment after SMILE by LASIK achieved excellent visual and refractive outcomes, although these results indicate that myopic LASIK retreatment after primary myopic SMILE requires a different nomogram than for myopic LASIK re-treatment after primary myopic LASIK. [J Refract Surg. 2018;34(9):578-588.].
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Reinstein DZ, Carp GI, Archer TJ, Vida RS. Inferior pseudo-hinge fulcrum technique and intraoperative complications of laser in situ keratomileusis retreatment after small-incision lenticule extraction. J Cataract Refract Surg 2018; 44:1355-1362. [PMID: 30287159 DOI: 10.1016/j.jcrs.2018.07.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/05/2018] [Accepted: 07/17/2018] [Indexed: 11/28/2022]
Abstract
PURPOSE To describe the evolution of a flap-lift technique for laser in situ keratomileusis (LASIK) retreatment after small-incision lenticule extraction (SMILE) and report the incidence of complications. SETTING London Vision Clinic, London, United Kingdom. DESIGN Retrospective case series. METHODS All retreatments between September 2013 and January 2017 were included. A bimanual inferior pseudo-hinge fulcrum flap-lift technique was developed to minimize the chance of tearing or entering the small incision. A flap lifter and a McPherson forceps were inserted into the inferior one third of the flap, slightly angled up to avoid perforating the small-incision lenticule extraction interface. One instrument provided countertraction, and the second separated the interface superiorly, keeping the tip away from the incision. One instrument was held against the hinge for the second instrument to separate the inferior one third. The incidence of intraoperative complications was analyzed. RESULTS The study evaluated 162 retreatments (4.12%) for 3933 small-incision lenticule extraction treatments (1-year maturity). The retreatment was LASIK (n = 135), side-cut only (n = 1), cap-to-flap procedure (CIRCLE) (n = 3), or photorefractive keratectomy (n = 23). Two eyes (1.4%) had a tear to the small incision. The small-incision lenticule extraction interface was accessed in 8 eyes (5.8%), 1 (0.7%) centrally, and the interface was lifted in 1 eye (0.7%). There were no complications in the last 84 consecutive procedures (60%) using the finalized technique. CONCLUSION The bimanual inferior pseudo-hinge fulcrum decreased the risk for accessing the small-incision lenticule extraction interface or tearing the small incision.
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Affiliation(s)
- Dan Z Reinstein
- From the London Vision Clinic (Reinstein, Carp, Archer, Vida), London, and Biomedical Science Research Institute (Reinstein, Archer), University of Ulster, Coleraine, United Kingdom; Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France; Northern Ireland.
| | - Glenn I Carp
- From the London Vision Clinic (Reinstein, Carp, Archer, Vida), London, and Biomedical Science Research Institute (Reinstein, Archer), University of Ulster, Coleraine, United Kingdom; Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France; Northern Ireland
| | - Timothy J Archer
- From the London Vision Clinic (Reinstein, Carp, Archer, Vida), London, and Biomedical Science Research Institute (Reinstein, Archer), University of Ulster, Coleraine, United Kingdom; Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France; Northern Ireland
| | - Ryan S Vida
- From the London Vision Clinic (Reinstein, Carp, Archer, Vida), London, and Biomedical Science Research Institute (Reinstein, Archer), University of Ulster, Coleraine, United Kingdom; Department of Ophthalmology (Reinstein), Columbia University Medical Center, New York, New York, USA; Centre Hospitalier National d'Ophtalmologie (Reinstein), Paris, France; Northern Ireland
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Damgaard IB, Ang M, Farook M, Htoon HM, Mehta JS. Intraoperative Patient Experience and Postoperative Visual Quality After SMILE and LASIK in a Randomized, Paired-Eye, Controlled Study. J Refract Surg 2018; 34:92-99. [PMID: 29425387 DOI: 10.3928/1081597x-20171218-01] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 12/08/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare intraoperative and postoperative subjective patient experience after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK. METHODS In a prospective, randomized, paired-eye, single-masked clinical trial at Singapore National Eye Centre, 70 patients were randomly treated with SMILE and LASIK in each eye. The intraoperative questionnaire was completed immediately after surgery and included light perception and levels of anxiety, fear, and discomfort. The postoperative 1- and 3-month questionnaires evaluated severity of light sensitivity, eye discomfort, eye dryness, excessive tearing, gritty sensation, glare, halos, blurring, and fluctuations in vision. RESULTS Average discomfort scores were higher during tissue manipulation in SMILE (1.9 ± 0.9) than flap lifting in LASIK (1.59 ± 0.8) (P = .020) but comparable during docking and laser application (P > .249). Fear scores were lower in SMILE than LASIK during docking (2.6 ± 1.6 vs 3.4 ± 1.9, P = .024) but similar during occasional blackout, laser application, and lenticule/flap manipulation (P > .364). Fear scores were generally higher in patients with intraoperative suction loss (n = 3). For SMILE, light sensitivity, eye discomfort, blurring, and fluctuations in vision improved from 1 to 3 months (P < .039). For LASIK, improvements were reported for light sensitivity, eye discomfort, eye dryness, gritty sensation, and fluctuations in vision from 1 to 3 months (P < .046). At 1 month, patients experienced more blurring after SMILE than LASIK (2.1 ± 0.8 vs 1.8 ± 0.7, P = .025), but with no differences in any of the visual symptoms at 3 months. CONCLUSIONS Tissue manipulation may be more uncomfortable during SMILE than LASIK, but not more frightening. Subjective visual symptoms were comparable after 3 months. [J Refract Surg. 2018;34(2):92-99.].
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Ganesh S, Brar S, Arra RR. Refractive lenticule extraction small incision lenticule extraction: A new refractive surgery paradigm. Indian J Ophthalmol 2018; 66:10-19. [PMID: 29283117 PMCID: PMC5778540 DOI: 10.4103/ijo.ijo_761_17] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Small incision lenticule extraction (SMILE), a variant of refractive lenticule extraction technology is becoming increasingly popular, as a flapless and minimally invasive form of laser vision correction (LVC) for the treatment of myopia and myopic astigmatism. This review aims at summarizing the principles, surgical technique, and clinical outcomes in terms of visual and refractive results, safety, efficacy, postoperative dry eye, aberrations, and biomechanics of SMILE and its comparison with other conventional techniques of LVC, such as laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Recent advancements in the laser frequency and energy delivery patterns, instrumentation, and surgical techniques have shown significant improvement in the visual recovery and outcomes after SMILE, compared to the initial results published by Sekundo and Shah et al. Most of the recently published literature on long-term outcomes of SMILE shows excellent stability of the procedure, especially for higher myopia. In terms of the postoperative dry eye, SMILE shows a clear advantage over LASIK as numerous studies have shown significant differences about the Schirmer's, Tear film break up time, corneal sensitivity, and corneal nerve regeneration to be better following SMILE compared to LASIK. There is some evidence that since the Bowman's membrane (BM) and the anterior lamellae remain intact after SMILE, this may be a potential advantage for corneal biomechanics over LASIK and PRK where the BM is either severed or ablated, respectively, however, the data on biomechanics are inconclusive at present. Overall, this procedure has proved to be promising, delivering equivalent, or better visual and refractive results to LASIK and providing clear advantage in terms of being a flapless, minimally invasive procedure with minimal pain and postoperative discomfort thus offering high patient satisfaction.
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Affiliation(s)
- Sri Ganesh
- Department of Phaco-Refractive, Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
| | - Sheetal Brar
- Department of Phaco-Refractive, Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
| | - Raghavender Reddy Arra
- Department of Phaco-Refractive, Nethradhama Superspeciality Eye Hospital, Bengaluru, Karnataka, India
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Shajari M, Wanner E, Rusev V, Mir Mohi Sefat S, Mayer WJ, Kohnen T, Priglinger S, Kook D. Corneal Densitometry after Femtosecond Laser-Assisted In Situ Keratomileusis (Fs-LASIK) and Small Incision Lenticule Extraction (SMILE). Curr Eye Res 2018. [PMID: 29537886 DOI: 10.1080/02713683.2018.1431288] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To compare corneal densitometry values after Femtosecond Laser-Assisted In Situ Keratomileusis (Fs-LASIK) and Small Incision Lenticule Extraction (SMILE) using Scheimpflug Imaging. METHODS Our retrospective clinical trial included a total of 146 eyes where 57 eyes underwent Fs-LASIK and 89 eyes underwent SMILE. Examinations with a Pentacam Scheimpflug device (Oculus, Wetzlar, Germany) were performed before surgery, 1 week, 1 month, 3 months, 6 months, and 1 year after surgery. Detailed data of all four concentric optical zones were acquired - central 0-2 mm, 2-6 mm, 6-10 mm and 10-12 mm. The cornea was divided into anterior 120 µm, middle and posterior 60 µm sections. Values were analyzed during follow-up comparing Fs-LASIK and SMILE. RESULTS No statistically significant differences in corneal density were detected. The central 0-2 mm anterior area demonstrated a mean 1-year value of 17.99 grayscale units (GSU) ± 0.89 (range 16.60-19.50) after Fs-LASIK versus 17.96 GSU ± 0.98 (range 16.40-20.00) after SMILE. Three months after surgery there was a slight temporary density increase in the 6-10 mm anterior annulus in the LASIK group - 22.19 (SD = 3.99, range: 15.60-30.50) compared to SMILE - 20.39 (SD = 3.79, range 14.70-36.30). CONCLUSION There were no statistically significant short or long-term differences in postoperative corneal densitometry after LASIK and SMILE, demonstrating SMILE is not inferior in this regard. Known delayed visual acuity recovery after SMILE in relation to LASIK could not be correlated with changes in corneal density.
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Affiliation(s)
- Mehdi Shajari
- a Department of Ophthalmology , Goethe University , Frankfurt , Germany
| | - Emanuel Wanner
- b Department of Ophthalmology , Ludwig Maximilians University , Munich , Germany
| | - Vladimir Rusev
- a Department of Ophthalmology , Goethe University , Frankfurt , Germany
| | | | - Wolfgang J Mayer
- b Department of Ophthalmology , Ludwig Maximilians University , Munich , Germany
| | - Thomas Kohnen
- a Department of Ophthalmology , Goethe University , Frankfurt , Germany
| | - Siegfried Priglinger
- b Department of Ophthalmology , Ludwig Maximilians University , Munich , Germany
| | - Daniel Kook
- c Smile Eyes Eye Clinic Munich Airport , Munich , Germany
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Torky MA, Alzafiri YA. Visual and refractive outcomes of small-incision lenticule extraction in mild, moderate, and high myopia: Six-month results. J Cataract Refract Surg 2017; 43:459-465. [DOI: 10.1016/j.jcrs.2017.01.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 12/13/2016] [Accepted: 01/03/2017] [Indexed: 11/25/2022]
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Comparison of femtosecond and excimer laser platforms available for corneal refractive surgery. Curr Opin Ophthalmol 2016; 27:316-22. [PMID: 27031540 DOI: 10.1097/icu.0000000000000268] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW The evolution of laser technology has left today's refractive surgeon with a choice between multiple laser platforms. The purpose of this review is to compare currently available femtosecond and excimer laser platforms, providing a summary of current evidence. RECENT FINDINGS Femtosecond lasers create LASIK flaps with better accuracy, uniformity, and predictability than mechanical microkeratomes. Newer higher-frequency femtosecond platforms elicit less inflammation, producing better visual outcomes. SMILE achieved similar safety, efficacy, and predictability as LASIK with greater preservation of corneal nerves and biomechanical strength. The emergence of wavefront technology has resulted in improved excimer laser treatments. Comparisons of wavefront-guided and wavefront-optimized treatments suggest that there is an advantage to using wavefront-guided platforms in terms of visual acuity and quality of vision. Topography-guided ablations are another well tolerated and effective option, especially in eyes with highly irregular corneas. SUMMARY Advances in femtosecond and excimer laser technology have not only improved the safety and efficacy of refractive procedures, but have also led to the development of promising new treatment modalities, such as SMILE and the use of wavefront-guided and topography-guided ablation. Future studies and continued technological progress will help to better define the optimal use of these treatment platforms.
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Son GS, Lee SC, Lim TH. Clinical Outcome of Small Incision Lenticule Extraction including Visual Quality Analysis. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2016. [DOI: 10.3341/jkos.2016.57.4.562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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