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Verma S, Hesser J, Mosquera SA. Cross Sectional Analysis of Impact of Seasonal Changes on Excimer Laser Ablation Performance on Polymethyl Methacrylate (PMMA). Vision (Basel) 2023; 7:50. [PMID: 37489329 PMCID: PMC10366815 DOI: 10.3390/vision7030050] [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: 04/26/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 07/26/2023] Open
Abstract
Seasonal changes and varying degree of corneal hydration has been linked to excimer laser corneal ablation rates. The use of PMMA as a calibration material in refractive lasers is well established. However, PMMA ablation may be equally affected by seasonal variations in temperature and humidity, in turn affecting the calibration process. The aim of this work is to analyze the effect of seasonal changes in PMMA performance using SCHWIND AMARIS laser system. PET and PMMA ablations conducted in climate-controlled environment with 826 consecutive AMARIS systems manufactured over 6 years were retrospectively analyzed. Lasers were stratified depending on seasons and months of the year. Metrics like single laser pulse fluence, nominal number of laser pulses, mean performance, standard deviation, and technical performance of system were compared to global average values. Cyclic winter-summer variation was confirmed with seasons winter and summer showing statistically significant variations with respect to global values. Metric technical performance showed deeper PMMA ablation performance in summertime, with maximum seasonal deviation of 6%. Results were consistently confirmed in seasonal as well as monthly analyses. These findings could help minimize variance among laser systems by implementing compensation factors depending on seasons such that laser systems installed worldwide follow the same trend line of variation.
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Affiliation(s)
- Shwetabh Verma
- Biomedical Engineering Office, Research and Development, SCHWIND Eye-Tech-Solutions, 63801 Kleinostheim, Germany
| | - Juergen Hesser
- Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, 69117 Heidelberg, Germany
- Mannheim Institute for Intelligent Systems in Medicine (MIISM), Heidelberg University, 69117 Heidelberg, Germany
- Central Institute for Computer Engineering (ZITI), Heidelberg University, 69117 Heidelberg, Germany
- CZS Heidelberg Center for Model-Based AI, Heidelberg University, 69117 Heidelberg, Germany
| | - Samuel Arba Mosquera
- Biomedical Engineering Office, Research and Development, SCHWIND Eye-Tech-Solutions, 63801 Kleinostheim, Germany
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Wu Y, Wang Y, Zhang Z, Yu X. Corneal stromal dehydration and optimal stromal exposure time during corneal refractive surgery measured using a three-dimensional optical profiler. Graefes Arch Clin Exp Ophthalmol 2022; 260:4005-4013. [PMID: 35876884 DOI: 10.1007/s00417-022-05764-w] [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: 01/21/2022] [Revised: 05/27/2022] [Accepted: 07/09/2022] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To quantitatively analyze human corneal stromal dehydration and estimate proper corneal stromal exposure time during corneal refractive surgery. METHODS The central thickness changes over time in 34 pieces of human corneal tissue were measured using a white light interferometer. The corneal stromal tissue was obtained by femtosecond laser small incision lenticule extraction. The thickness-time dehydration fitting curves were drawn, and the determination coefficient R2 was calculated. The differences in the fitting curve equation coefficients were compared between the thin and thick lenticule groups. The optimal stromal exposure time was calculated under various conditions, including different optical zones and allowable refractive errors. RESULTS A water loss variation model was successfully established. Linear and quadratic fitting curves were drawn, and the determination coefficient R2 values were significantly close to 1. The average values of R2 for quadratic curves and linear phases 1, 2, and 3 were 0.998 ± 0.002, 0.995 ± 0.007, 0.996 ± 0.003, and 0.984 ± 0.035, respectively. The optimal stromal exposure time varied under different optical zones and allowable diopter error conditions. Taking the allowable error of 0.50 D and the optical zone size of 6.5 mm as an example, the optimal time was approximately 24 s. CONCLUSIONS The dehydration rate of the human corneal stroma is nonlinear, and the quadratic stromal thickness-time dehydration fitting curve is more in line with the actual water loss trend. The length of the stroma exposure time may affect the postoperative refractive accuracy after corneal refractive surgery.
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Affiliation(s)
- Yanan Wu
- Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, No 4. Gansu Road, He-ping District, Tianjin, 300020, China.,Nankai University Affiliated Eye Hospital, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Yan Wang
- Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, No 4. Gansu Road, He-ping District, Tianjin, 300020, China. .,Nankai University Affiliated Eye Hospital, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
| | - Zimiao Zhang
- Tianjin Key Laboratory of High Speed Cutting & Precision Machining, Tianjin University of Technology and Education, Tianjin, China
| | - Xingchen Yu
- The Second Hospital of Tianjin Medical University, Tianjin, China
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Sahay P, Bafna RK, Reddy JC, Vajpayee RB, Sharma N. Complications of laser-assisted in situ keratomileusis. Indian J Ophthalmol 2021; 69:1658-1669. [PMID: 34146007 PMCID: PMC8374806 DOI: 10.4103/ijo.ijo_1872_20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/19/2020] [Accepted: 10/27/2020] [Indexed: 11/25/2022] Open
Abstract
Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.
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Affiliation(s)
- Pranita Sahay
- Department of Ophthalmology, Lady Hardinge Medical College, New Delhi, India
| | - Rahul Kumar Bafna
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Jagadesh C Reddy
- Cataract and Refractive Surgery Services, Cornea Institute, L V Prasad Eye Institute, L V Prasad Marg, Roan No-2, Banjara Hills, Hyderabad, Telangana, India
| | - Rasik B Vajpayee
- Vision Eye Institute, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Australia
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Verma S, Kehrer T, Hesser J, Arba Mosquera S. Analysis of Impact of Humidity and Temperature on Excimer Laser Ablation of Polyethylene Terephthalate, Polymethylmethacrylate, and Porcine Corneal Tissue. Lasers Surg Med 2019; 52:627-638. [PMID: 31758590 DOI: 10.1002/lsm.23190] [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] [Accepted: 11/06/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVES To analyze the impact of humidity and temperature on excimer laser ablation of polyethylene terephthalate (PET), polymethylmethacrylate (PMMA) and porcine corneal tissue, and an ablation model to compensate for the temperature and humidity changes on ablation efficiency. STUDY DESIGN/MATERIALS AND METHODS The study was conducted using an AMARIS 1050RS (Schwind eye-tech-solutions) placed inside a climate chamber at ACTS. Ablations were performed on PET, PMMA, and porcine cornea. The impact of a wide range of temperature (~18°C to ~30°C) and relative humidity (~25% to ~80%) on laser ablation outcomes was tested using nine climate test settings. For porcine eyes, change in defocus was calculated from the difference of post-ablation to pre-ablation average keratometry readings. Laser scanning deflectometry was performed to measure refractive change achieved in PMMA. Multiple linear regression was performed using the least square method with predictive factors: temperature, relative humidity, time stamp. Influence of climate settings was modeled for pulse energy, pulse fluence, ablation efficiency on PMMA and porcine cornea tissue. RESULTS Temperature changes did not affect laser pulse energy, pulse fluence (PET), and ablation efficiency (on PMMA or porcine corneal tissue) significantly. Changes in relative humidity were critical and significantly affected laser pulse energy, high fluence and low fluence. The opposite trend was observed between the ablation performance on PMMA and porcine cornea. CONCLUSIONS The proposed well-fitting multi-linear model can be utilized for compensation of temperature and humidity changes on ablation efficiency. Based on this model, a working window for optimum operation has been found (temperature 18°C to 28°C and relative humidity 25% to 65%) for a maximum deviation of ±2.5% in ablation efficiency in PMMA and porcine corneal tissue. Lasers Surg. Med. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Shwetabh Verma
- Biomedical Engineering Office, Research and Development, SCHWIND eye-tech-solutions, Kleinostheim, D-63801, Germany.,Experimental Radiation Oncology, University Medical Center Mannheim, Heidelberg University, Mannheim, D-68167, Germany.,Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, 69120, Germany.,Central Institute for Computer Engineering (ZITI), Heidelberg University, Heidelberg, 69120, Germany
| | - Tobias Kehrer
- Department of Theoretical Physics III, University of Würzburg, Würzburg, 97074, Germany
| | - Jürgen Hesser
- Experimental Radiation Oncology, University Medical Center Mannheim, Heidelberg University, Mannheim, D-68167, Germany.,Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, 69120, Germany.,Central Institute for Computer Engineering (ZITI), Heidelberg University, Heidelberg, 69120, Germany
| | - Samuel Arba Mosquera
- Biomedical Engineering Office, Research and Development, SCHWIND eye-tech-solutions, Kleinostheim, D-63801, Germany
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Abstract
PURPOSE To identify the potential risk factors that increase the likelihood of requiring retreatment after refractive surgery. METHODS This retrospective study included patients who underwent laser in situ keratomileusis or photorefractive keratectomy between January 2005 and December 2012 at the Care-Vision Laser Centers, Tel-Aviv, Israel. Patients were divided into 2 groups according to whether they underwent additional refractive surgery (retreatment) during the study period. RESULTS Overall, 41,504 eyes (n = 21,313) were included in the final analysis of this study. Throughout the study period, there was a significant reduction in the 2-year annual retreatment rates with a decline from 4.52% for primary surgeries done in 2005 to 0.18% for surgeries performed in 2012 (quadratic R = 0.96, P < 0.001). The retreatment group had significantly higher preoperative age, maximum keratometric power, sphere, cylinder, and better best-corrected visual acuity. They were more likely to have preoperative hyperopia, photorefractive keratectomy as opposed to laser in situ keratomileusis, intraoperative higher humidity conditions and lower temperature, and higher ablation depths. Significant differences in retreatment rates were found between the 5 high-volume surgeons (>1500 procedures performed) ranging from 0.48 to 3.14% (P < 0.0001). Multiple logistic regression analysis demonstrated that age, astigmatism, hyperopia, temperature, and surgeon's experience all significantly affected the need for retreatment. CONCLUSIONS The following factors significantly increase the need for refractive retreatment: older preoperative age, higher degrees of astigmatism, hyperopia, colder operating room temperature, and less surgeon experience. Some of these factors may be incorporated into nomograms to reduce future retreatment rates.
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Hood CT, Shtein RM, Veldheer D, Hussain M, Niziol LM, Musch DC, Mian SI. The effect of humidity and temperature on visual outcomes after myopic corneal laser refractive surgery. Clin Ophthalmol 2016; 10:2231-2236. [PMID: 27853351 PMCID: PMC5104295 DOI: 10.2147/opth.s118503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Objective To determine whether procedure room environmental conditions are associated with outcomes after myopic laser in situ keratomileusis (LASIK) or laser-assisted keratomileusis (LASEK). Design Retrospective chart review. Participants Eight hundred sixty-three eyes of 458 consecutive patients at a university-based academic practice. Methods We reviewed the medical records of consecutive patients who underwent LASIK or LASEK over a 3-year period. Linear mixed regression models were used to investigate the association of laser room temperature and humidity with the outcomes of visual acuity and postoperative manifest spherical equivalent refraction. Repeated measures logistic regression models were used for the outcomes of diffuse lamellar keratitis (DLK) and need for enhancement surgery. Results Subjects were on an average 38.6 years old at the time of surgery (standard deviation [SD] =10.3) and the average spherical equivalent refraction of eyes was 3.8 diopters (SD =2.03). Regression models did not reveal a significant association between temperature and uncorrected distance visual acuity (UDVA) or corrected distance visual acuity (CDVA), or between humidity and UDVA (P>0.05 for all). However, increased humidity was associated with a small but statistically significant improvement in CDVA after LASIK at 1 day, 1 month, 3 months, and 1 year postoperatively (P<0.05 for all). There was no significant association between temperature and humidity and the need for enhancement, the incidence of DLK, or postoperative manifest refraction. Conclusion While increased laser room humidity was consistently associated with small improvements in CDVA after myopic LASIK over time, variations in room temperature and humidity were not associated with UDVA, the need for enhancement, the incidence of DLK, or refraction after myopic LASIK or LASEK.
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Affiliation(s)
- Christopher T Hood
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI
| | - Roni M Shtein
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI
| | - Daniel Veldheer
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI
| | - Munira Hussain
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI
| | - Leslie M Niziol
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI
| | - David C Musch
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI; Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA
| | - Shahzad I Mian
- Department of Ophthalmology and Visual Sciences, University of Michigan W.K. Kellogg Eye Center, Ann Arbor, MI
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Iijima K, Kamiya K, Shimizu K, Igarashi A, Komatsu M. Demographics of patients having cataract surgery after laser in situ keratomileusis. J Cataract Refract Surg 2015; 41:334-8. [PMID: 25661126 DOI: 10.1016/j.jcrs.2014.05.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To retrospectively assess the demographics of patients having cataract surgery in eyes with previous laser in situ keratomileusis (LASIK). SETTING Department of Ophthalmology, Kitasato University, Kanagawa, and Sanno Hospital, Tokyo, Japan. DESIGN Retrospective case series. METHODS This study evaluated eyes of consecutive patients scheduled for cataract surgery after previous LASIK (Group 1). The control groups comprised eyes with axial lengths (ALs) matched with ALS in Group 1 (Group 2) and all eyes scheduled for cataract surgery (Group 3). Assessed were age, sex, corrected distance visual acuity, manifest refraction, keratometry (K) readings, corneal astigmatism, and corneal higher-order aberrations (HOAs). RESULTS Group 1 comprised 40 eyes of 40 patients; Group 2, 606 eyes of 606 patients; and Group 3, 3642 eyes of 3642 patients. The mean age at cataract surgery of patients in Group 1 was 54.6 years ± 8.1 (SD), which was significantly younger than in Group 2 (by approximately 10 years) and Group 3 (by approximately 15 years) (P < .001, Student t test). In Group 1, 70.0% of patients were men, a significantly higher percentage than in Groups 2 and 3 (P < .05, Fisher exact test). The rate of corneal HOAs was significantly higher in Group 1 than in Groups 2 and 3 (P < .05, Student t test). There were no significant differences in other demographics except in K readings. CONCLUSION A long AL and an increase in corneal HOAs might contribute to a tendency for cataract surgery to be performed earlier in eyes in which LASIK has been performed. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Kei Iijima
- From the Department of Ophthalmology (Iijima, Kamiya, Shimizu, Igarashi), University of Kitasato School of Medicine, Kanagawa, and the Department of Ophthalmology (Komatsu), Sanno Hospital, Tokyo, Japan
| | - Kazutaka Kamiya
- From the Department of Ophthalmology (Iijima, Kamiya, Shimizu, Igarashi), University of Kitasato School of Medicine, Kanagawa, and the Department of Ophthalmology (Komatsu), Sanno Hospital, Tokyo, Japan.
| | - Kimiya Shimizu
- From the Department of Ophthalmology (Iijima, Kamiya, Shimizu, Igarashi), University of Kitasato School of Medicine, Kanagawa, and the Department of Ophthalmology (Komatsu), Sanno Hospital, Tokyo, Japan
| | - Akihito Igarashi
- From the Department of Ophthalmology (Iijima, Kamiya, Shimizu, Igarashi), University of Kitasato School of Medicine, Kanagawa, and the Department of Ophthalmology (Komatsu), Sanno Hospital, Tokyo, Japan
| | - Mari Komatsu
- From the Department of Ophthalmology (Iijima, Kamiya, Shimizu, Igarashi), University of Kitasato School of Medicine, Kanagawa, and the Department of Ophthalmology (Komatsu), Sanno Hospital, Tokyo, Japan
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Luger MHA, Ewering T, Arba-Mosquera S. Analysis of seasonal changes in residual refraction 1-year after corneal laser refractive surgery: a retrospective study. JOURNAL OF OPTOMETRY 2014; 7:138-146. [PMID: 25000869 PMCID: PMC4087176 DOI: 10.1016/j.optom.2013.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/05/2013] [Accepted: 12/05/2013] [Indexed: 06/03/2023]
Abstract
PURPOSE To analyze the effect of seasonal changes in residual refraction 1-year after corneal refractive surgery using the SCHWIND AMARIS laser system. METHODS 5740 consecutive treatments have been retrospectively reviewed. For all eyes, aspheric treatments were planned with the Custom Ablation Manager software and the ablations were performed with the SCHWIND AMARIS system (SCHWIND eye-tech-solutions). Seasonal outcomes were evaluated in terms of residual refraction stratified per treatment month, as well as stratified per year season. Student's T test comparing stratified values with global ones was used for the statistical analysis. RESULTS Treatments performed in April, June, August, September, and October showed relative undercorrections of the spherical equivalent (SE) (-0.09D), whereas treatments performed in January, February, and March showed relative overcorrections of the SE (+0.13D). Similarly, treatments performed in spring and summer showed relative undercorrections of the SE (-0.04D), whereas treatments performed in winter showed relative overcorrections of the SE (+0.10D). CONCLUSIONS Seasonal differences in refractive outcomes were observed among a large scale population. The effect of these environmental variables on refractive outcomes warrants further evaluation.
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Neuhaus-Richard I, Frings A, Görsch IC, Druchkiv V, Katz T, Linke SJ, Richard G. Do outside temperature and sunlight duration influence the outcome of laser refractive surgery? Results from the Hamburg Weather Study. Clin Ophthalmol 2014; 8:1129-37. [PMID: 24966665 PMCID: PMC4063864 DOI: 10.2147/opth.s57717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To examine the impact of temperature and sunlight duration on refractive and visual outcome of laser-assisted in situ keratomileusis (LASIK) in myopic eyes. SETTING University Medical Center Hamburg-Eppendorf, Germany, and Care Vision Refractive Centers, Germany. DESIGN Retrospective, cross-sectional data analysis. METHODS This study comprised 1,052 eyes of 1,052 consecutive myopic patients (419 males, 633 females; mean age at surgery 35.0±9.0 years) with a mean preoperative refractive spherical equivalent (SE) of -3.88±1.85 diopters (D). Two subgroups were defined, comprising patients undergoing surgery during either meteorological winter or summer. Manifest refraction, uncorrected, and corrected distant visual acuity (UDVA and CDVA) were assessed pre- and postoperatively. We applied robust regression analysis with efficiency index (EI), safety index (SI), and postoperative SE (in D) as dependent variables. RESULTS At the 1-month (33.0±5.0 days) follow-up, the mean postoperative SE was -0.18±0.44 D. Bivariate comparisons showed that statistically significant better EI was related to days with lower temperature. We obtained a significant difference for SI which suggested that low temperature had a positive influence on SI. No change by more than one line on LogMAR scale was obtained. CONCLUSION Although being statistically significant, there was no clinically relevant difference in the outcome of LASIK, which demonstrates its highly standardized quality. Prospective, longitudinal studies are warranted to address meteorotropic reactions through evaluating defined meteorological parameters.
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Affiliation(s)
- Ines Neuhaus-Richard
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany
| | - Andreas Frings
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany
| | | | - Vasyl Druchkiv
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany
| | - Toam Katz
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany ; Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stephan Johannes Linke
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany ; Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gisbert Richard
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Germany
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Variation in the effectiveness of refractive surgery during the year: results from the Hamburg Weather Study. J Cataract Refract Surg 2014; 40:1139-46. [PMID: 24957434 DOI: 10.1016/j.jcrs.2013.11.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/31/2013] [Accepted: 11/11/2013] [Indexed: 11/23/2022]
Abstract
PURPOSE To examine the impact of seasonality on the refractive and visual outcomes of laser in situ keratomileusis (LASIK) in myopic eyes. SETTING Department of Ophthalmology and Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. DESIGN Retrospective cross-sectional data analysis. METHODS Two subgroups were defined. The first comprised patients having surgery during meteorological winter and the second, patients having surgery during meteorological summer. The manifest refraction and uncorrected and corrected visual acuities were assessed preoperatively and postoperatively. Robust regression analysis was applied with the efficacy index, safety index, and postoperative SE as dependent variables. RESULTS This study comprised 1052 eyes of 1052 consecutive myopic patients (419 men, 633 women; mean age at surgery 35.0 years ± 9.0 [SD]) with a mean preoperative refractive spherical equivalent (SE) of -3.88 ± 1.85 diopters (D). At the 1-month follow-up (mean 33.0 ± 5.0 days), the mean postoperative SE was -0.18 ± 0.44 D. The efficacy index was 0.023 higher in eyes with refractive surgery during summer than in eyes treated during winter (P=.032), indicating less efficacy during winter. The differences in the safety index and postoperative SE between summer and winter were not statistically significant. No eye had a change of more than 1 line on the logMAR scale (corrected distance visual acuity). CONCLUSIONS Although the difference in the efficacy index was statistically significant, the difference in the outcomes of LASIK was not clinically relevant, which shows the procedure's highly standardized reliability. Prospective longitudinal studies are warranted to address meteorotropic reactions by evaluating defined meteorological parameters. FINANCIAL DISCLOSURE(S) No author has a financial or proprietary interest in any material or method mentioned.
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Neuhaus-Richard I, Frings A, Ament F, Görsch IC, Druchkiv V, Katz T, Linke SJ, Richard G. Do air pressure and wind speed influence the outcome of myopic laser refractive surgery? Results from the Hamburg Weather Study. Int Ophthalmol 2014; 34:1249-58. [PMID: 24562594 DOI: 10.1007/s10792-014-9923-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 02/11/2014] [Indexed: 11/30/2022]
Abstract
Laser in situ keratomileusis (LASIK) is one of the dominant procedures for the surgical correction of refractive errors. Meteorotropic reaction has been described regarding the field of ophthalmology. This study was thus initiated to assess the impact of air pressure and wind speed on the refractive and visual outcome of LASIK in myopic eyes. Our study comprised 1,052 eyes of 1,052 consecutive myopic patients (419 males, 633 females; mean age at surgery 35.0 ± 9.0 years) with mean preoperative refractive spherical equivalent (SE) of -3.88 ± 1.85 diopters (D). Two subgroups were defined, which had undergone surgery either during meteorological winter or summer. Manifest refraction, uncorrected and corrected visual acuity were assessed pre- and post-operatively. We applied robust regression analysis with efficiency index (EI), safety index, and postoperative SE (D) as dependent variables. At the 1-month (33.0 ± 5.0 days) follow-up, the mean postoperative SE was -0.18 ± 0.44 D. Bivariate comparisons showed that statistically significant better EI was related to days with low to moderate air-pressure. This was confirmed by robust regression analysis. Moderate to high wind speed was related to more appropriate postoperative SE. No change by more than one line on logMar scale was obtained. Although being statistically significant, there is no clinically relevant difference in outcome of LASIK, which demonstrates its highly standardized quality. Prospective, longitudinal studies are warranted to address meteorotropic reactions through evaluating individual risk profiles.
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Affiliation(s)
- Ines Neuhaus-Richard
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
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