Comparison of clinical outcomes following small incision lenticule extraction performed with the Visumax 800 versus Visumax 500 femtosecond laser

Comparison of clinical outcomes following small incision lenticule extraction performed with the Visumax 800 versus Visumax 500 femtosecond laser | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Comparison of clinical outcomes following small incision lenticule extraction performed with the Visumax 800 versus Visumax 500 femtosecond laser Bu Ki Kim, Young Taek Chung This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5385801/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 15 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract This study compared clinical outcomes between small incision lenticule extraction (SMILE) procedures performed with the Visumax 800 and Visumax 500 femtosecond lasers. We compared the clinical outcomes of 100 eyes of 50 patients who underwent SMILE using the Visumax 800 (SMILE Pro group) and 100 eyes of 50 patients who underwent SMILE using the Visumax 500 femtosecond laser (SMILE group). Outcomes were assessed at a 3-month follow-up, including standard visual outcomes, optic zone decentration, and corneal higher-order aberrations (HOAs). The mean lenticule creation time was significantly shorter in the SMILE Pro group (10.33 ± 0.82 seconds) than the SMILE group (28.27 ± 2.34 seconds, P < 0.001). At 3 months postoperatively, the groups had no significant differences in uncorrected or corrected distance visual acuity, residual refractive errors, or corneal HOAs. However, the optic zone decentration was significantly smaller in the SMILE Pro group than in the SMILE group ( P < 0.001), and the vertical coma induction was significantly lower in the SMILE Pro group compared with the SMILE group ( P = 0.034), suggesting that the Visumax 800 provides enhanced centration accuracy, reduced vertical coma induction, and faster lenticule creation, demonstrating comparable efficacy, safety, and predictability to the Visumax 500. Health sciences/Diseases/Eye diseases/Refractive errors Health sciences/Diseases/Eye diseases/Vision disorders SMILE Small incision lenticule extraction Visumax 800 SMILE Pro Figures Figure 1 Figure 2 Figure 3 INTRODUCTION It has been more than 10 years since small incision lenticule extraction (SMILE) for refractive correction was first performed using the Visumax 500 femtosecond laser (Carl Zeiss Meditec, Dublin, CA). 1 Although SMILE is a relatively new procedure compared with LASIK, it has been widely accepted given its good efficacy, safety, predictability, lack of flap-related complications, and rapid postoperative recovery. 2 , 3 Many studies have evaluated the efficacy of SMILE, including the long-term clinical results, complications, nomograms, and characteristics of the lenticular surface via electron microscopy. 2 – 6 However, SMILE conducted using the Visumax 500 has some limitations, including the risk of suction loss, the absence of an active eye tracking system, and the inability to adjust for cyclotorsion. 4 The second-generation Visumax 800, introduced in 2021, improves on the limitations of the first-generation Visumax 500. The SMILE procedure conducted using the Visumax 800 was named SMILE Pro, and it includes software to assist with centration and cyclotorsion adjustments as well as a faster laser speed. Reinstein et al. 7 reported good early outcomes of SMILE with Visumax 800 for treating myopia. However, to the best of our knowledge, only a few studies have compared SMILE outcomes using the Visumax 500 and Visumax 800 lasers, and none have examined decentration. In the current study, we aimed to compare the visual and refractive outcomes between SMILE conducted using the Visumax 500 versus the Visumax 800. Furthermore, we compared the optic zone decentration and corneal higher-order aberration (HOAs) induction between the two surgical methods. METHODS Study Participants This was a retrospective, comparative study that included patients with myopia or myopic astigmatism who underwent SMILE using the Visumax 500 (SMILE group) or Visumax 800 (SMILE Pro group) at the Onnuri Smile Eye Clinic, Seoul, Republic of Korea, between August 2023 and October 2023. The inclusion criteria were aged 19 years or older, corrected distance visual acuity (CDVA) of 20/30 or better, myopia from − 0.5 to -8.0 diopters (D), astigmatism up to -4.0 D, stable refraction over 2 years, central corneal thickness (CCT) > 480 µm, and calculated postoperative residual bed thickness > 300 µm. The exclusion criteria were active or residual ocular disease, a prior history of ocular surgery or trauma, and topographic evidence of keratoconus. Clinical records were included in the analysis if the patients had completed a 3-month postoperative follow-up assessment. The study protocol was approved by the Public Internal Regulatory Board of the Ministry of Health and Welfare, Korea (P01-202402-01-020). All participants were thoroughly notified about the potential surgical complications and provided informed consent. This study was conducted in accordance with the tenets of the Declaration of Helsinki. Surgical Protocol In all cases, the procedural target was emmetropia, and the same surgeon (KBK) performed the surgery. The same nomogram was applied in both groups, as previously described. 8 In the SMILE group, the Visumax 500 (500 kHz) was used during the procedure. The laser parameters, lenticule, cap, and incision geometry were as previously described. 8 During the SMILE procedure, the centration target was set as the corneal vertex via the tear film mark technique. The patient was asked to focus on a green dot. Then, the bed was slowly raised to enlarge the tear film generated by the cone and cornea to approximately 80%. The suction ports were activated to keep the patient’s eye fixated in the correct position. In the SMILE Pro group, the Visumax 800 (2,000 kHz) was used during the procedure. The laser parameters, lenticule, cap, and incision geometry were the same as in the SMILE group. The lenticule was centered using the CentraLign system, which enabled the (x,y) location of the corneal vertex from the dual-rotating Scheimpflug (DRS) analyzer (Galilei, Ziemer Ophthalmology, Port, Switzerland) to be manually entered in advance into the software. The surgeon was then guided in aligning the cornea via visual overlays displayed on the treatment monitor. As the cornea contacted the contact glass, the treatment monitor displayed the distance between the corneal vertex and the lenticule center. The surgeon used a joystick to adjust the two points until they matched and then initiated the suction when the distance between them was ≤ 0.1 mm. The lenticule extraction and postoperative management for both groups were the same as previously described. 8 Postoperative evaluation The patients were assessed at 1 day, 1 week, 1 month, and 3 months postoperatively. At each visit, we assessed the uncorrected distance visual acuity (UDVA), CDVA, and manifest refraction, and we also performed the slit-lamp examination. The optic zone decentration and corneal HOAs were assessed at 3 months using a DRS analyzer. The decentration was measured using a difference map of the tangential curvature from the preoperative and 3-month postoperative examinations. The corneal HOAs were analyzed over a 6-mm central diameter, and the root mean square (RMS) values of HOAs including the oblique trefoil (OT), vertical coma (VC), horizontal coma (HC), horizontal trefoil (HT), spherical aberration (SA), and total HOAs were calculated. All postoperative complications were noted. Statistical analysis Statistical analysis was performed using SPSS (version 20.0; IBM Corporation). All data were subjected to the Kolmogorov-Smirnov test and were normally distributed. The values are expressed as means ± standard deviation. For statistical analyses of visual acuity, the logarithm of the minimum angle of resolution (logMAR) was used. For the comparison between the two groups, independent sample t -test or chi-square test was used. For comparison between the preoperative and postoperative values, paired t -test was used. P value ≤ 0.05 was regarded as statistically significant. RESULTS The SMILE and SMILE Pro groups each contained data from 100 eyes. There were no significant differences between the two groups in age, refractive errors, CCT, optic zone, preoperative pupillary offset, or corneal HOAs (Table 1 ). Table 1 Patient demographics. SMILE SMILE Pro P value Patients, eyes (N) 50, 100 50, 100 N/A Age (years) 26.14 ± 4.27 26.24 ± 5.56 0.920* Gender (M/F) 54/46 60/40 0.294† Refractive errors (D) Spherical Cylindrical SE -4.06 ± 1.68 -1.18 ± 0.85 -4.65 ± 1.86 -3.87 ± 1.54 -1.4 ± 0.95 -4.57 ± 1.6 0.383* 0.079* 0.724* CCT (µm) 564.6 ± 31.27 562.9 ± 25.88 0.676* Optic zone (mm) 6.42 ± 0.3 6.43 ± 0.23 0.749* Preoperative pupillary offset (mm) X-axis Y-axis 0.13 ± 0.1 0.15 ± 0.12 0.13 ± 0.09 0.14 ± 0.11 0.594* 0.445* Pupil diameter (mm) 6.92 ± 0.52 6.75 ± 0.66 0.087* HOAs (µm) Oblique trefoil Vertical coma Horizontal coma Horizontal trefoil Spherical aberration Total HOAs 0.12 ± 0.08 0.16 ± 0.1 0.15 ± 0.11 0.09 ± 0.07 0.2 ± 0.07 0.45 ± 0.1 0.11 ± 0.09 0.17 ± 0.13 0.14 ± 0.11 0.11 ± 0.08 0.22 ± 0.06 0.48 ± 0.14 0.474* 0.425* 0.745* 0.164* 0.160* 0.082* N = number; N/A = not applicable; M/F = male/female; D = diopters; SE = spherical equivalent; CCT = central corneal thickness; HOAs = higher-order aberrations. *Independent sample t -test; †chi-square test. No intraoperative complications were detected in either group. The time required for lenticule creation in the SMILE Pro group was 10.33 ± 0.82 seconds, which was significantly shorter than that in the SMILE group (28.27 ± 2.34 seconds; P < 0.001). There was no significant difference in the time required for lenticule separation and extraction between the two groups. The optic zone decentration was significantly smaller in the SMILE Pro group compared with the SMILE group in terms of the x-axis, y-axis, and total (Table 2 ). Table 2 Comparison of intraoperative findings between the two surgical procedures SMILE SMILE pro P value* Intraoperative complication 0 0 N/A Time for lenticule creation (seconds) 28.27 ± 2.34 10.33 ± 0.82 < 0.001 Time for lenticule removal (seconds) 35.33 ± 13.5 30.73 ± 9.55 0.101 Optic zone decentration (mm) X-axis Y-axis Total 0.21 ± 0.19 0.32 ± 0.21 0.38 ± 0.26 0.16 ± 0.15 0.13 ± 0.1 0.22 ± 0.15 0.021 < 0.001 < 0.001 N/A = not applicable. *Independent-sample t -test. Table 3 shows the postoperative results of both groups. There were no significant differences between the two groups in postoperative UDVA, CDVA, residual refractive errors, CCT, efficacy index, and safety index. Table 3 Comparison of postoperative findings between the two surgical procedures at 3 months SMILE SMILE Pro P value* UDVA (logMAR) -0.08 ± 0.04 -0.07 ± 0.05 0.539 CDVA (logMAR) -0.1 ± 0.06 -0.09 ± 0.05 0.957 Refractive errors (D) Spherical Cylindrical SE -0.09 ± 0.38 -0.36 ± 0.23 -0.27 ± 0.36 -0.05 ± 0.39 -0.32 ± 0.23 -0.21 ± 0.39 0.552 0.250 0.337 CCT (µm) 473.6 ± 35.4 469.8 ± 29.6 0.408 Efficacy index 1.06 ± 1.07 1.04 ± 0.15 0.292 Safety index 1.12 ± 0.21 1.09 ± 0.19 0.417 HOAs (µm) Oblique trefoil Vertical coma Horizontal coma Horizontal trefoil Spherical aberration Total HOAs 0.16 ± 0.12 0.24 ± 0.18 0.18 ± 0.13 0.11 ± 0.09 0.3 ± 0.16 0.64 ± 0.21 0.14 ± 0.11 0.2 ± 0.14 0.18 ± 0.13 0.12 ± 0.1 0.29 ± 0.12 0.63 ± 0.17 0.235 0.383 0.983 0.266 0.853 0.766 UDVA = uncorrected distance visual acuity; logMAR = logarithm of the minimum angle of resolution; CDVA = corrected distance visual acuity; D = diopters; SE = spherical equivalent; CCT = central corneal thickness; HOAs = higher-order aberrations. *Independent-sample t -test. Figures 1 and 2 show the nine standard graphs used for reporting the outcomes of refractive surgery for the SMILE and SMILE Pro groups, respectively. The postoperative UDVA was ≥ 20/20 in 100% of eyes in both groups, and the postoperative CDVA was the same or better than the preoperative CDVA in 90% and 92% of eyes in the SMILE and SMILE Pro groups, respectively. The spherical equivalent was within ± 0.5 D in 76% and 80% of eyes in the SMILE and SMILE Pro groups, respectively, and it was ± 1.0 D in 99% of eyes in both groups. Residual astigmatism was ≤ 0.5 D in 83% and 90% of eyes in the SMILE and SMILE Pro groups, respectively, and it was ≤ 1.0 D in 100% of eyes in both groups. A scatter plot between target induced astigmatism (TIA) and surgically induced astigmatism (SIA) showed that astigmatic correction tended to have a linear relationship in both groups. However, the trend line for the SMILE Pro group was more closely aligned with direct proportionality than that for the SMILE group (the slope of the trend line was 0.845 vs. 0.899, with an R 2 of 0.8857 vs. 0.9095 for the SMILE and SMILE Pro groups, respectively). The angle of error (AE) ≤ 0.5° was 58% and 62% for the SMILE and SMILE Pro groups, respectively. After the surgery, both groups showed significant increases in OT, VC, HC, SA, and total HOAs ( P = 0.04, < 0.001, 0.002, < 0.001, and < 0.001, respectively in the SMILE group, 0.027, 0.045, < 0.001, < 0.001, and < 0.001, respectively in the SMILE Pro group). The increase in VC was significantly lower in the SMILE pro group than in the SMILE group ( P = 0.034), whereas there was no significant difference in the increase of OT, HC, HT, SA, or total HOA between the two groups ( P = 0.535, 0.680, 0.967, 0.395, and 0.238, respectively) (Fig. 3 ). There were no significant differences between the two groups in any postoperative HOAs (Table 3 ). Additionally, no visually threatening complications such as infection, corneal ectasia, and severe diffuse lamellar keratitis during the follow-up period in either group. DISCUSSION Centration of the lenticule during SMILE with the Visumax 500 is performed manually, and a standardized method for determining the center of the optic zone has not yet been established. Therefore, methods for centration during SMILE with the Visumax 500 have been introduced based on various reference points such as the pupil center, corneal center, and coaxial corneal light reflex. 9 , 10 It is widely accepted that centration to the visual axis is a key factor in optimal visual outcomes in terms of the maintenance of functional corneal morphology after refractive surgeries. 11 Many studies have shown the corneal vertex to be the closest corneal intercept to the ideal visual axis, 9 – 12 and various techniques for determining the corneal vertex during SMILE have been introduced, such as the topographic comparison technique, tear film mark technique, and triple marking technique. 13 , 14 However, since centration in these techniques is not performed by looking directly at the corneal vertex, there is a possibility that decentration could occur especially when the patient’s cooperation is poor or the operator lacks expertise enough. Optic zone decentration may not only cause complications such as halo, glare, and diplopia, but it can also induce irregular astigmatism and HOAs. 9 , 11 In this study, we set the corneal vertex as the target for the lenticule center using the tear film mark technique in the SMILE group. Several studies have shown that the tear film mark technique during SMILE leads to less optic zone decentration compared with SMILE performed based on the pupil center or FS-LASIK. 12 – 14 In the present study, the mean optic zone decentration in the SMILE group was 0.38 ± 0.26 mm. This was not higher than the optic zone decentration in several previous studies (i.e., 0.14–0.7 mm) during SMILE with the Visumax 500 centered on the corneal vertex. 14 In the present study, the mean optic zone decentration in the SMILE Pro group was 0.22 ± 0.15 mm, which was significantly smaller than that in the SMILE group. This could be a consequence of using the CentraLign software (included in the Visumax 800 package), which displays the vector difference between the corneal vertex and the treatment center on the monitor in real-time during docking. This system may help the surgeon meticulously control the centration process and prevent optic zone decentration. Despite the high efficacy, safety, and predictability of SMILE, surgical treatments for astigmatism tend toward undercorrection relative to the degree of preoperative astigmatism. 15 – 17 The degree of astigmatism undercorrection is reported to be 11–16%, and although the cause has not yet been clearly identified, decentration has been suggested as one of the reasons. 15 – 17 However, several studies have reported that small degrees of decentration is not associated with low astigmatism correction. For instance, Huang et al. 18 reported no significant association between decentration during SMILE and postoperative astigmatism in patients with high astigmatism. In our study, we found no significant difference in postoperative astigmatism between the two groups, although the SMILE group had significantly more decentration than the SMILE Pro group. Nonetheless, the SMILE pro group tended to have superior astigmatism correction according to the vector analysis. Specifically, 83% and 90% of eyes had ≤ 0.5 D of residual astigmatism in the SMILE and SMILE Pro groups respectively (Fig. 1 G and 2 G), and the slopes of the trend lines between TIA and SIA were 0.845 and 0.899 for the SMILE and SMILE Pro groups, respectively (Fig. 1 H and 2 H). Furthermore, 58% and 62% of eyes in the SMILE and SMILE Pro groups, respectively, had an AE ≤ 5° (Fig. 1 I and 2 I). However, we did not include many eyes with high astigmatism in the present study, and to the best of our knowledge, no studies have examined the relationship between decentration and astigmatism correction in SMILE. More detailed comparative studies on astigmatism correction are needed. Although many studies have reported favorable clinical results of SMILE, significant corneal HOAs inductions have also been reported. 9 – 12 This aberrometric phenomenon has been associated with several factors, such as changes in corneal morphology, postoperative corneal remodeling, and optic zone decentration. 9 , 19 In our study, both groups showed significant increases in OT, VC, HC, SA, and total HOAs after surgery. The increase in VC was significantly lower in the SMILE pro group than in the SMILE group, and there were no significant differences in the degree to which the other variables increased between the two groups. Coma aberrations represent the characteristics of eye asymmetry and reflect irregular, tilt, and decentration. 20 Because the optics and laser delivery systems in the Visumax 800 system are identical to those of the Visumax 500, and because we used the same laser parameters in both groups, the significantly lower degree of VC induction in the SMILE Pro group might reflect the decreased decentration of the optic zone. Lee et al. 9 reported that eyes with decentration ≤ 0.335 mm showed significantly less VC induction compared with eyes with decentration > 0.335 mm after SMILE, and a significant relationship was observed between decentration and VC induction in eyes with decentration > 0.335 mm. In our study, the time required for lenticule creation was significantly different between the SMILE and SMILE Pro groups (28.27 ± 2.34 and 10.33 ± 0.82 seconds, respectively). This is because the Visumax 800 has a faster laser pulse frequency (2,000 kHz) than the Visumax 500 (500 kHz). In general, lenticule creation takes 25–30 seconds with the Visumax 500. 21 If the patient moves their eye or head during the laser treatment, suction loss occurs. However, this can be managed depending on the stage at which it occurs. There is no consensus regarding the optimal management of suction loss, and the reported outcomes vary among literature studies. 22 Large studies have demonstrated that the incidence of suction loss during SMILE using Visumax 500 ranges from 0.17–5.06% of patients. 23 , 24 Reinstein et al. 25 reported that 65% of cases of suction loss occurred 10 seconds after the creation of the lenticule during SMILE using Visumax 500. Therefore, we may expect more than half of the suction loss incidence reduction in SMILE with Visumax 800 compared to SMILE with Visumax 500; large sample studies would be required to verify this. Our study has some limitations. First, it included only 3 months of follow-up data. However, refractive outcomes have been found to change during the 10 years after SMILE with the Visumax 500. 2 , 3 Additionally, although the femtosecond laser cutting sequence of the Visumax 800 is identical to that of the Visumax 500, there could be differences in long-term changes in clinical results. Another limitation is the small sample size. Studies including larger sample sizes and longer follow-up periods are needed for a more accurate comparison. This study showed that the efficacy, safety, and predictability of SMILE procedures are comparable between the Visumax 500 and Visumax 800. However, the lenticule creation time was significantly shorter when using the Visumax 800 versus the Visumax 500, and SMILE with the Visumax 800 was superior to SMILE with the Visumax 500 in terms of centration accuracy and VC induction. These differences might be due to the use of the CentraLign software and the faster repetition rate of the Visumax 800. Further studies are warranted to confirm our findings. Declarations Competing interests The authors declare no competing interests. Author Contribution B.K.K. contributed to the conceptualization, methodology, data collection, writing a manuscript. Y.T.C. provided all technical and material support, and critically revised the manuscript. Data Availability B.K.K. had comprehensive access to all data in this study and accepts full responsibility for its integrity and the accuracy of the data analysis. References Sekundo, W. et al. Blum M. First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results. J. Cataract Refract. Surg. 34 , 1513–1520 (2008). Blum, M., Lauer, A. S., Kunert, K. S. & Sekundo, W. 10-year results of small incision lenticule extraction. J. Refract. Surg. 35 , 618–623 (2019). Xia, F. et al. Ten-year outcomes following small incision lenticule extraction for up to -10 dioptres myopia. Clin. Exp. Optom. 107 , 285–290 (2024). Asif, M. I. et al. Complications of small incision lenticule extraction. Indian J. Ophthalmol. 68 , 2711–2722 (2020). Cui, T. et al. Applying machine learning techniques in nomogram prediction and analysis for SMILE treatment. Am. J. Ophthalmol. 210 , 71–77 (2020). Ziebarth, N. M. et al. Surface quality of human corneal lenticules after SMILE assessed using environmental scanning electron microscopy. J. Refract. Surg. 30 , 388–393 (2014). Reinstein, D. Z., Archer, T. J., Potter, J. G., Gupta, R. & Wiltfang, R. Refractive and visual outcomes of SMILE for compound myopic astigmatism with the VISUMAX 800. J. Refract. Surg. 39 , 294–301 (2023). Kim, B. K. & Chung, Y. T. Comparison of changes in corneal thickness and curvature after myopia correction between SMILE and FS-LASIK. J. Refract. Surg. 39 , 15–22 (2023). Lee, H. et al. Relationship between decentration and induced corneal higher-order aberrations following small-incision lenticule extraction procedure. Invest. Ophthalmol. Vis. Sci. 59 , 2316–2324 (2018). Chan, T. C. Y. et al. Effect of corneal curvature on optical zone decentration and its impact on astigmatism and higher-order aberrations in SMILE and LASIK. Graefes Arch. Clin. Exp. Ophthalmol. 257 , 233–240 (2019). Liu, Q. et al. Review on centration, astigmatic axis alignment, pupil size and optical zone in SMILE. Asia Pac. J. Ophthalmol. (Phila) . 8 , 385–390 (2019). Liu, M. et al. Decentration of optical zone center and its impact on visual outcomes following SMILE. Cornea 34 , 392–397 (2015). Liu, S., Zhang, X., You, Z. & Zhou, X. Comparison of the distribution of lenticule decentration following SMILE by pupil center or tear film mark centration. J. Refract. Surg. 36 , 239–246 (2020). Liang, C. & Yan, H. Methods of corneal vertex centration and evaluation of effective optical zone in small incision lenticule extraction. Ophthalmic Res. 66 , 717–726 (2023). Pedersen, I. B., Ivarsen, A. & Hjortdal, J. Changes in astigmatism, densitometry, and aberrations after SMILE for low to high myopic astigmatism: A 12-month prospective study. J. Refract. Surg. 33 , 11–17 (2017). Ivarsen, A. & Hjortdal, J. Correction of myopic astigmatism with small incision lenticule extraction. J. Refract. Surg. 30 , 240–247 (2014). Kanellopoulos, A. J. Topography-guided LASIK versus small incision lenticule extraction (SMILE) for myopia and myopic astigmatism: a randomized, prospective, contralateral eye study. J. Refract. Surg. 33 , 306–312 (2017). Huang, J., Zhou, X. & Qian, Y. Decentration following femtosecond laser small incision lenticule extraction (SMILE) in eyes with high astigmatism and its impact on visual quality. BMC Ophthalmol. 19 , 151 (2019). Zhao, P. F. et al. Comparison of correcting myopia and astigmatism with SMILE or FS-LASIK and postoperative higher-order aberrations. Int. J. Ophthalmol. 14 , 523–528 (2021). Lombardo, M. & Lombardo, G. Wave aberration of human eyes and new descriptors of image optical quality and visual performance. J. Cataract Refract. Surg. 36 , 313–331 (2010). Wong, C. W., Chan, C., Tan, D. & Mehta, J. S. Incidence and management of suction loss in refractive lenticule extraction. J. Cataract Refract. Surg. 40 , 2002–2010 (2014). Wan, K. H., Lin, T. P. H., Lai, K. H. W., Liu, S. & Lam, D. S. C. Options and results in managing suction loss during small-incision lenticule extraction. J. Cataract Refract. Surg. 47 , 933–941 (2021). Pradhan, K. R. et al. Quality control outcomes analysis of small-incision lenticule extraction for myopia by a novice surgeon at the first refractive surgery unit in Nepal during the first 2 years of operation. J. Cataract Refract. Surg. 42 , 267–274 (2016). Osman, I. M., Awad, R., Shi, W. & Abou Shousha, M. Suction loss during femtosecond laser-assisted small-incision lenticule extraction: Incidence and analysis of risk factors. J. Cataract Refract. Surg. 42 , 246–250 (2016). Reinstein, D. Z., Archer, T. J., Vida, R. S. & Carp, G. I. Suction stability management in small incision lenticule extraction: incidence and outcomes of suction loss in 4000 consecutive procedures. Acta Ophthalmol. 98 , e72–e80 (2020). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 15 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 17 Mar, 2025 Reviews received at journal 16 Mar, 2025 Reviews received at journal 28 Feb, 2025 Reviewers agreed at journal 26 Feb, 2025 Reviewers agreed at journal 20 Feb, 2025 Reviewers invited by journal 19 Feb, 2025 Editor assigned by journal 06 Feb, 2025 Editor invited by journal 18 Nov, 2024 Submission checks completed at journal 16 Nov, 2024 First submitted to journal 04 Nov, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5385801","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":389408455,"identity":"8fada5fb-1098-48c0-94dd-8fe142fc720b","order_by":0,"name":"Bu Ki Kim","email":"","orcid":"","institution":"Onnuri Smile Eye Clinic","correspondingAuthor":false,"prefix":"","firstName":"Bu","middleName":"Ki","lastName":"Kim","suffix":""},{"id":389408456,"identity":"9bdd3bc7-2c64-4dc4-8990-fa835d1b0777","order_by":1,"name":"Young Taek Chung","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAv0lEQVRIiWNgGAWjYHACNjDJz5BAvAaIFskGqBYeorUYHCBWi8H95mePeXfUyhsfT34mdYPhjpw9QS3H2MyNec8cN9x25pmZdA7DM2PCthzjYZPmbTuWYHYjAaTlcGIP0VqMZ6R/A2mpJ1ZLTYKBRA7YlgSCDpM8lmYmObftgOGMM2+KrXMMDhv2HCCghe/w4WcSb9vq5Pnb0zfezqk4LM/eQECLAsTMwzB3EnIVEMhDzKwjQukoGAWjYBSMWAAARxw8xlOo5SwAAAAASUVORK5CYII=","orcid":"","institution":"Onnuri Eye Hosipital","correspondingAuthor":true,"prefix":"","firstName":"Young","middleName":"Taek","lastName":"Chung","suffix":""}],"badges":[],"createdAt":"2024-11-04 07:38:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5385801/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5385801/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-98041-9","type":"published","date":"2025-07-15T15:57:27+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":71874743,"identity":"a90ce691-832c-44f3-9a29-2fdc3cc6b3db","added_by":"auto","created_at":"2024-12-19 10:51:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1554897,"visible":true,"origin":"","legend":"\u003cp\u003eNine standard graphs showing the visual and refractive outcomes of SMILE with the Visumax 500 femtosecond laser (Carl Zeiss Meditec AG) at 3 months postoperatively. CDVA = corrected distance visual acuity; D = diopters; Postop = postoperative; Preop = preoperative; SEQ = spherical equivalent refraction; SIA = surgically induced astigmatism; TIA = target induced astigmatism; UDVA = uncorrected distance visual acuity.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5385801/v1/c27124490e61bfdd8ec3d980.png"},{"id":71874754,"identity":"bf9bc204-b203-42c1-b48d-3b705d4fb070","added_by":"auto","created_at":"2024-12-19 10:51:20","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1535511,"visible":true,"origin":"","legend":"\u003cp\u003eNine standard graphs showing the visual and refractive outcomes of SMILE with the Visumax 800 femtosecond laser (Carl Zeiss Meditec AG) at 3 months postoperatively. CDVA = corrected distance visual acuity; D = diopters; Postop = postoperative; Preop = preoperative; SEQ = spherical equivalent refraction; SIA = surgically induced astigmatism; TIA = target induced astigmatism; UDVA = uncorrected distance visual acuity.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5385801/v1/06b825f05c287e6d59bcb459.png"},{"id":71876386,"identity":"e6665264-6d7c-4d69-9d87-a9e1f6f4c0a7","added_by":"auto","created_at":"2024-12-19 10:59:19","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":105711,"visible":true,"origin":"","legend":"\u003cp\u003eRMS of total HOAs and individual Zernike coefficients in the SMILE and SMILE Pro groups at 3 months postoperatively. Error bars indicate standard errors and * indicates \u003cem\u003eP\u003c/em\u003e \u0026lt; .05. RMS = root mean square; HOAs = higher-order aberrations; HC = horizontal coma; HT = horizontal trefoil; OT = oblique trefoil; SA = spherical aberration; VC = vertical coma.\u003c/p\u003e\n\u003cp\u003eChanges after surgery were calculated via paired \u003cem\u003et\u003c/em\u003e-test.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5385801/v1/1673a77774ba50055defd723.jpg"},{"id":87219733,"identity":"0a3b3e5e-2294-4705-b374-8539759b3d46","added_by":"auto","created_at":"2025-07-21 16:05:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3771493,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5385801/v1/5b36b9bd-4035-4ce6-a2db-e81bf09530fa.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparison of clinical outcomes following small incision lenticule extraction performed with the Visumax 800 versus Visumax 500 femtosecond laser","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eIt has been more than 10 years since small incision lenticule extraction (SMILE) for refractive correction was first performed using the Visumax 500 femtosecond laser (Carl Zeiss Meditec, Dublin, CA).\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e Although SMILE is a relatively new procedure compared with LASIK, it has been widely accepted given its good efficacy, safety, predictability, lack of flap-related complications, and rapid postoperative recovery.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e Many studies have evaluated the efficacy of SMILE, including the long-term clinical results, complications, nomograms, and characteristics of the lenticular surface via electron microscopy.\u003csup\u003e\u003cspan additionalcitationids=\"CR3 CR4 CR5\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e However, SMILE conducted using the Visumax 500 has some limitations, including the risk of suction loss, the absence of an active eye tracking system, and the inability to adjust for cyclotorsion.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe second-generation Visumax 800, introduced in 2021, improves on the limitations of the first-generation Visumax 500. The SMILE procedure conducted using the Visumax 800 was named SMILE Pro, and it includes software to assist with centration and cyclotorsion adjustments as well as a faster laser speed. Reinstein et al.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e reported good early outcomes of SMILE with Visumax 800 for treating myopia. However, to the best of our knowledge, only a few studies have compared SMILE outcomes using the Visumax 500 and Visumax 800 lasers, and none have examined decentration.\u003c/p\u003e \u003cp\u003eIn the current study, we aimed to compare the visual and refractive outcomes between SMILE conducted using the Visumax 500 versus the Visumax 800. Furthermore, we compared the optic zone decentration and corneal higher-order aberration (HOAs) induction between the two surgical methods.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Participants\u003c/h2\u003e \u003cp\u003eThis was a retrospective, comparative study that included patients with myopia or myopic astigmatism who underwent SMILE using the Visumax 500 (SMILE group) or Visumax 800 (SMILE Pro group) at the Onnuri Smile Eye Clinic, Seoul, Republic of Korea, between August 2023 and October 2023. The inclusion criteria were aged 19 years or older, corrected distance visual acuity (CDVA) of 20/30 or better, myopia from \u0026minus;\u0026thinsp;0.5 to -8.0 diopters (D), astigmatism up to -4.0 D, stable refraction over 2 years, central corneal thickness (CCT)\u0026thinsp;\u0026gt;\u0026thinsp;480 \u0026micro;m, and calculated postoperative residual bed thickness\u0026thinsp;\u0026gt;\u0026thinsp;300 \u0026micro;m. The exclusion criteria were active or residual ocular disease, a prior history of ocular surgery or trauma, and topographic evidence of keratoconus. Clinical records were included in the analysis if the patients had completed a 3-month postoperative follow-up assessment. The study protocol was approved by the Public Internal Regulatory Board of the Ministry of Health and Welfare, Korea (P01-202402-01-020). All participants were thoroughly notified about the potential surgical complications and provided informed consent. This study was conducted in accordance with the tenets of the Declaration of Helsinki.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgical Protocol\u003c/h3\u003e\n\u003cp\u003eIn all cases, the procedural target was emmetropia, and the same surgeon (KBK) performed the surgery. The same nomogram was applied in both groups, as previously described.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn the SMILE group, the Visumax 500 (500 kHz) was used during the procedure. The laser parameters, lenticule, cap, and incision geometry were as previously described.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e During the SMILE procedure, the centration target was set as the corneal vertex via the tear film mark technique. The patient was asked to focus on a green dot. Then, the bed was slowly raised to enlarge the tear film generated by the cone and cornea to approximately 80%. The suction ports were activated to keep the patient\u0026rsquo;s eye fixated in the correct position.\u003c/p\u003e \u003cp\u003eIn the SMILE Pro group, the Visumax 800 (2,000 kHz) was used during the procedure. The laser parameters, lenticule, cap, and incision geometry were the same as in the SMILE group. The lenticule was centered using the CentraLign system, which enabled the (x,y) location of the corneal vertex from the dual-rotating Scheimpflug (DRS) analyzer (Galilei, Ziemer Ophthalmology, Port, Switzerland) to be manually entered in advance into the software. The surgeon was then guided in aligning the cornea via visual overlays displayed on the treatment monitor. As the cornea contacted the contact glass, the treatment monitor displayed the distance between the corneal vertex and the lenticule center. The surgeon used a joystick to adjust the two points until they matched and then initiated the suction when the distance between them was \u0026le;\u0026thinsp;0.1 mm.\u003c/p\u003e \u003cp\u003eThe lenticule extraction and postoperative management for both groups were the same as previously described.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\n\u003ch3\u003ePostoperative evaluation\u003c/h3\u003e\n\u003cp\u003eThe patients were assessed at 1 day, 1 week, 1 month, and 3 months postoperatively. At each visit, we assessed the uncorrected distance visual acuity (UDVA), CDVA, and manifest refraction, and we also performed the slit-lamp examination. The optic zone decentration and corneal HOAs were assessed at 3 months using a DRS analyzer. The decentration was measured using a difference map of the tangential curvature from the preoperative and 3-month postoperative examinations. The corneal HOAs were analyzed over a 6-mm central diameter, and the root mean square (RMS) values of HOAs including the oblique trefoil (OT), vertical coma (VC), horizontal coma (HC), horizontal trefoil (HT), spherical aberration (SA), and total HOAs were calculated. All postoperative complications were noted.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using SPSS (version 20.0; IBM Corporation). All data were subjected to the Kolmogorov-Smirnov test and were normally distributed. The values are expressed as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. For statistical analyses of visual acuity, the logarithm of the minimum angle of resolution (logMAR) was used. For the comparison between the two groups, independent sample \u003cem\u003et\u003c/em\u003e-test or chi-square test was used. For comparison between the preoperative and postoperative values, paired \u003cem\u003et\u003c/em\u003e-test was used. \u003cem\u003eP\u003c/em\u003e value\u0026thinsp;\u0026le;\u0026thinsp;0.05 was regarded as statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe SMILE and SMILE Pro groups each contained data from 100 eyes. There were no significant differences between the two groups in age, refractive errors, CCT, optic zone, preoperative pupillary offset, or corneal HOAs (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003ePatient demographics.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSMILE\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSMILE Pro\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePatients, eyes (N)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50, 100\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50, 100\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eN/A\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eAge (years)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26.14\u0026thinsp;\u0026plusmn;\u0026thinsp;4.27\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26.24\u0026thinsp;\u0026plusmn;\u0026thinsp;5.56\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.920*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eGender (M/F)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e54/46\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e60/40\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.294\u0026dagger;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eRefractive errors (D)\u003c/p\u003e\n\u003cp\u003eSpherical\u003c/p\u003e\n\u003cp\u003eCylindrical\u003c/p\u003e\n\u003cp\u003eSE\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-4.06\u0026thinsp;\u0026plusmn;\u0026thinsp;1.68\u003c/p\u003e\n\u003cp\u003e-1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85\u003c/p\u003e\n\u003cp\u003e-4.65\u0026thinsp;\u0026plusmn;\u0026thinsp;1.86\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-3.87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.54\u003c/p\u003e\n\u003cp\u003e-1.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.95\u003c/p\u003e\n\u003cp\u003e-4.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.383*\u003c/p\u003e\n\u003cp\u003e0.079*\u003c/p\u003e\n\u003cp\u003e0.724*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCCT (\u0026micro;m)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e564.6\u0026thinsp;\u0026plusmn;\u0026thinsp;31.27\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e562.9\u0026thinsp;\u0026plusmn;\u0026thinsp;25.88\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.676*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eOptic zone (mm)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.749*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePreoperative pupillary offset (mm)\u003c/p\u003e\n\u003cp\u003eX-axis\u003c/p\u003e\n\u003cp\u003eY-axis\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e\n\u003cp\u003e0.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e\n\u003cp\u003e0.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.594*\u003c/p\u003e\n\u003cp\u003e0.445*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePupil diameter (mm)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.92\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.66\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.087*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eHOAs (\u0026micro;m)\u003c/p\u003e\n\u003cp\u003eOblique trefoil\u003c/p\u003e\n\u003cp\u003eVertical coma\u003c/p\u003e\n\u003cp\u003eHorizontal coma\u003c/p\u003e\n\u003cp\u003eHorizontal trefoil\u003c/p\u003e\n\u003cp\u003eSpherical aberration\u003c/p\u003e\n\u003cp\u003eTotal HOAs\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e\n\u003cp\u003e0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e\n\u003cp\u003e0.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e\n\u003cp\u003e0.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e\n\u003cp\u003e0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e\n\u003cp\u003e0.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e\n\u003cp\u003e0.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003c/p\u003e\n\u003cp\u003e0.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e\n\u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e\n\u003cp\u003e0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e\n\u003cp\u003e0.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.474*\u003c/p\u003e\n\u003cp\u003e0.425*\u003c/p\u003e\n\u003cp\u003e0.745*\u003c/p\u003e\n\u003cp\u003e0.164*\u003c/p\u003e\n\u003cp\u003e0.160*\u003c/p\u003e\n\u003cp\u003e0.082*\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003eN\u0026thinsp;=\u0026thinsp;number; N/A\u0026thinsp;=\u0026thinsp;not applicable; M/F\u0026thinsp;=\u0026thinsp;male/female; D\u0026thinsp;=\u0026thinsp;diopters; SE\u0026thinsp;=\u0026thinsp;spherical equivalent; CCT\u0026thinsp;=\u0026thinsp;central corneal thickness; HOAs\u0026thinsp;=\u0026thinsp;higher-order aberrations.\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e*Independent sample \u003cem\u003et\u003c/em\u003e-test; \u0026dagger;chi-square test.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eNo intraoperative complications were detected in either group. The time required for lenticule creation in the SMILE Pro group was 10.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.82 seconds, which was significantly shorter than that in the SMILE group (28.27\u0026thinsp;\u0026plusmn;\u0026thinsp;2.34 seconds; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There was no significant difference in the time required for lenticule separation and extraction between the two groups. The optic zone decentration was significantly smaller in the SMILE Pro group compared with the SMILE group in terms of the x-axis, y-axis, and total (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparison of intraoperative findings between the two surgical procedures\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSMILE\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSMILE pro\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value*\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eIntraoperative complication\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eN/A\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTime for lenticule creation (seconds)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e28.27\u0026thinsp;\u0026plusmn;\u0026thinsp;2.34\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.82\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTime for lenticule removal (seconds)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e35.33\u0026thinsp;\u0026plusmn;\u0026thinsp;13.5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e30.73\u0026thinsp;\u0026plusmn;\u0026thinsp;9.55\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.101\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eOptic zone decentration (mm)\u003c/p\u003e\n\u003cp\u003eX-axis\u003c/p\u003e\n\u003cp\u003eY-axis\u003c/p\u003e\n\u003cp\u003eTotal\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19\u003c/p\u003e\n\u003cp\u003e0.32\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003c/p\u003e\n\u003cp\u003e0.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003c/p\u003e\n\u003cp\u003e0.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e\n\u003cp\u003e0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.021\u003c/p\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003eN/A\u0026thinsp;=\u0026thinsp;not applicable.\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e*Independent-sample \u003cem\u003et\u003c/em\u003e-test.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows the postoperative results of both groups. There were no significant differences between the two groups in postoperative UDVA, CDVA, residual refractive errors, CCT, efficacy index, and safety index.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparison of postoperative findings between the two surgical procedures at 3 months\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSMILE\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSMILE Pro\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value*\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eUDVA (logMAR)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e-0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e-0.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.539\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCDVA (logMAR)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e-0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e-0.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.957\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eRefractive errors (D)\u003c/p\u003e\n\u003cp\u003eSpherical\u003c/p\u003e\n\u003cp\u003eCylindrical\u003c/p\u003e\n\u003cp\u003eSE\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-0.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.38\u003c/p\u003e\n\u003cp\u003e-0.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003c/p\u003e\n\u003cp\u003e-0.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.36\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e-0.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e\n\u003cp\u003e-0.32\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003c/p\u003e\n\u003cp\u003e-0.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.552\u003c/p\u003e\n\u003cp\u003e0.250\u003c/p\u003e\n\u003cp\u003e0.337\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCCT (\u0026micro;m)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e473.6\u0026thinsp;\u0026plusmn;\u0026thinsp;35.4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e469.8\u0026thinsp;\u0026plusmn;\u0026thinsp;29.6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.408\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eEfficacy index\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e1.06\u0026thinsp;\u0026plusmn;\u0026thinsp;1.07\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e1.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.292\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSafety index\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e1.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\"\u0026plusmn;\"\u003e\n\u003cp\u003e1.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.417\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eHOAs (\u0026micro;m)\u003c/p\u003e\n\u003cp\u003eOblique trefoil\u003c/p\u003e\n\u003cp\u003eVertical coma\u003c/p\u003e\n\u003cp\u003eHorizontal coma\u003c/p\u003e\n\u003cp\u003eHorizontal trefoil\u003c/p\u003e\n\u003cp\u003eSpherical aberration\u003c/p\u003e\n\u003cp\u003eTotal HOAs\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e\n\u003cp\u003e0.24\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003c/p\u003e\n\u003cp\u003e0.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003c/p\u003e\n\u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e\n\u003cp\u003e0.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/p\u003e\n\u003cp\u003e0.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e\n\u003cp\u003e0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003c/p\u003e\n\u003cp\u003e0.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003c/p\u003e\n\u003cp\u003e0.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e\n\u003cp\u003e0.29\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e\n\u003cp\u003e0.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e0.235\u003c/p\u003e\n\u003cp\u003e0.383\u003c/p\u003e\n\u003cp\u003e0.983\u003c/p\u003e\n\u003cp\u003e0.266\u003c/p\u003e\n\u003cp\u003e0.853\u003c/p\u003e\n\u003cp\u003e0.766\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003eUDVA\u0026thinsp;=\u0026thinsp;uncorrected distance visual acuity; logMAR\u0026thinsp;=\u0026thinsp;logarithm of the minimum angle of resolution; CDVA\u0026thinsp;=\u0026thinsp;corrected distance visual acuity; D\u0026thinsp;=\u0026thinsp;diopters; SE\u0026thinsp;=\u0026thinsp;spherical equivalent; CCT\u0026thinsp;=\u0026thinsp;central corneal thickness; HOAs\u0026thinsp;=\u0026thinsp;higher-order aberrations.\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e*Independent-sample \u003cem\u003et\u003c/em\u003e-test.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eFigures \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e show the nine standard graphs used for reporting the outcomes of refractive surgery for the SMILE and SMILE Pro groups, respectively. The postoperative UDVA was \u0026ge;\u0026thinsp;20/20 in 100% of eyes in both groups, and the postoperative CDVA was the same or better than the preoperative CDVA in 90% and 92% of eyes in the SMILE and SMILE Pro groups, respectively. The spherical equivalent was within \u0026plusmn;\u0026thinsp;0.5 D in 76% and 80% of eyes in the SMILE and SMILE Pro groups, respectively, and it was \u0026plusmn;\u0026thinsp;1.0 D in 99% of eyes in both groups. Residual astigmatism was \u0026le;\u0026thinsp;0.5 D in 83% and 90% of eyes in the SMILE and SMILE Pro groups, respectively, and it was \u0026le;\u0026thinsp;1.0 D in 100% of eyes in both groups. A scatter plot between target induced astigmatism (TIA) and surgically induced astigmatism (SIA) showed that astigmatic correction tended to have a linear relationship in both groups. However, the trend line for the SMILE Pro group was more closely aligned with direct proportionality than that for the SMILE group (the slope of the trend line was 0.845 vs. 0.899, with an R\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e of 0.8857 vs. 0.9095 for the SMILE and SMILE Pro groups, respectively). The angle of error (AE)\u0026thinsp;\u0026le;\u0026thinsp;0.5\u0026deg; was 58% and 62% for the SMILE and SMILE Pro groups, respectively.\u003c/p\u003e\n\u003cp\u003eAfter the surgery, both groups showed significant increases in OT, VC, HC, SA, and total HOAs (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.04, \u0026lt;\u0026thinsp;0.001, 0.002, \u0026lt;\u0026thinsp;0.001, and \u0026lt;\u0026thinsp;0.001, respectively in the SMILE group, 0.027, 0.045, \u0026lt;\u0026thinsp;0.001, \u0026lt;\u0026thinsp;0.001, and \u0026lt;\u0026thinsp;0.001, respectively in the SMILE Pro group). The increase in VC was significantly lower in the SMILE pro group than in the SMILE group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.034), whereas there was no significant difference in the increase of OT, HC, HT, SA, or total HOA between the two groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.535, 0.680, 0.967, 0.395, and 0.238, respectively) (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). There were no significant differences between the two groups in any postoperative HOAs (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eAdditionally, no visually threatening complications such as infection, corneal ectasia, and severe diffuse lamellar keratitis during the follow-up period in either group.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eCentration of the lenticule during SMILE with the Visumax 500 is performed manually, and a standardized method for determining the center of the optic zone has not yet been established. Therefore, methods for centration during SMILE with the Visumax 500 have been introduced based on various reference points such as the pupil center, corneal center, and coaxial corneal light reflex.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e It is widely accepted that centration to the visual axis is a key factor in optimal visual outcomes in terms of the maintenance of functional corneal morphology after refractive surgeries.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e Many studies have shown the corneal vertex to be the closest corneal intercept to the ideal visual axis,\u003csup\u003e\u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e and various techniques for determining the corneal vertex during SMILE have been introduced, such as the topographic comparison technique, tear film mark technique, and triple marking technique.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e However, since centration in these techniques is not performed by looking directly at the corneal vertex, there is a possibility that decentration could occur especially when the patient\u0026rsquo;s cooperation is poor or the operator lacks expertise enough. Optic zone decentration may not only cause complications such as halo, glare, and diplopia, but it can also induce irregular astigmatism and HOAs.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e In this study, we set the corneal vertex as the target for the lenticule center using the tear film mark technique in the SMILE group. Several studies have shown that the tear film mark technique during SMILE leads to less optic zone decentration compared with SMILE performed based on the pupil center or FS-LASIK.\u003csup\u003e\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e In the present study, the mean optic zone decentration in the SMILE group was 0.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26 mm. This was not higher than the optic zone decentration in several previous studies (i.e., 0.14\u0026ndash;0.7 mm) during SMILE with the Visumax 500 centered on the corneal vertex.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e In the present study, the mean optic zone decentration in the SMILE Pro group was 0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 mm, which was significantly smaller than that in the SMILE group. This could be a consequence of using the CentraLign software (included in the Visumax 800 package), which displays the vector difference between the corneal vertex and the treatment center on the monitor in real-time during docking. This system may help the surgeon meticulously control the centration process and prevent optic zone decentration.\u003c/p\u003e \u003cp\u003eDespite the high efficacy, safety, and predictability of SMILE, surgical treatments for astigmatism tend toward undercorrection relative to the degree of preoperative astigmatism.\u003csup\u003e\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e The degree of astigmatism undercorrection is reported to be 11\u0026ndash;16%, and although the cause has not yet been clearly identified, decentration has been suggested as one of the reasons.\u003csup\u003e\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e However, several studies have reported that small degrees of decentration is not associated with low astigmatism correction. For instance, Huang et al.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e reported no significant association between decentration during SMILE and postoperative astigmatism in patients with high astigmatism. In our study, we found no significant difference in postoperative astigmatism between the two groups, although the SMILE group had significantly more decentration than the SMILE Pro group. Nonetheless, the SMILE pro group tended to have superior astigmatism correction according to the vector analysis. Specifically, 83% and 90% of eyes had\u0026thinsp;\u0026le;\u0026thinsp;0.5 D of residual astigmatism in the SMILE and SMILE Pro groups respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eG and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eG), and the slopes of the trend lines between TIA and SIA were 0.845 and 0.899 for the SMILE and SMILE Pro groups, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eH and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eH). Furthermore, 58% and 62% of eyes in the SMILE and SMILE Pro groups, respectively, had an AE\u0026thinsp;\u0026le;\u0026thinsp;5\u0026deg; (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eI and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eI). However, we did not include many eyes with high astigmatism in the present study, and to the best of our knowledge, no studies have examined the relationship between decentration and astigmatism correction in SMILE. More detailed comparative studies on astigmatism correction are needed.\u003c/p\u003e \u003cp\u003eAlthough many studies have reported favorable clinical results of SMILE, significant corneal HOAs inductions have also been reported.\u003csup\u003e\u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e This aberrometric phenomenon has been associated with several factors, such as changes in corneal morphology, postoperative corneal remodeling, and optic zone decentration.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e In our study, both groups showed significant increases in OT, VC, HC, SA, and total HOAs after surgery. The increase in VC was significantly lower in the SMILE pro group than in the SMILE group, and there were no significant differences in the degree to which the other variables increased between the two groups. Coma aberrations represent the characteristics of eye asymmetry and reflect irregular, tilt, and decentration.\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e Because the optics and laser delivery systems in the Visumax 800 system are identical to those of the Visumax 500, and because we used the same laser parameters in both groups, the significantly lower degree of VC induction in the SMILE Pro group might reflect the decreased decentration of the optic zone. Lee et al.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e reported that eyes with decentration\u0026thinsp;\u0026le;\u0026thinsp;0.335 mm showed significantly less VC induction compared with eyes with decentration\u0026thinsp;\u0026gt;\u0026thinsp;0.335 mm after SMILE, and a significant relationship was observed between decentration and VC induction in eyes with decentration\u0026thinsp;\u0026gt;\u0026thinsp;0.335 mm.\u003c/p\u003e \u003cp\u003eIn our study, the time required for lenticule creation was significantly different between the SMILE and SMILE Pro groups (28.27\u0026thinsp;\u0026plusmn;\u0026thinsp;2.34 and 10.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.82 seconds, respectively). This is because the Visumax 800 has a faster laser pulse frequency (2,000 kHz) than the Visumax 500 (500 kHz). In general, lenticule creation takes 25\u0026ndash;30 seconds with the Visumax 500.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e If the patient moves their eye or head during the laser treatment, suction loss occurs. However, this can be managed depending on the stage at which it occurs. There is no consensus regarding the optimal management of suction loss, and the reported outcomes vary among literature studies.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e Large studies have demonstrated that the incidence of suction loss during SMILE using Visumax 500 ranges from 0.17\u0026ndash;5.06% of patients.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e Reinstein et al.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e reported that 65% of cases of suction loss occurred 10 seconds after the creation of the lenticule during SMILE using Visumax 500. Therefore, we may expect more than half of the suction loss incidence reduction in SMILE with Visumax 800 compared to SMILE with Visumax 500; large sample studies would be required to verify this.\u003c/p\u003e \u003cp\u003eOur study has some limitations. First, it included only 3 months of follow-up data. However, refractive outcomes have been found to change during the 10 years after SMILE with the Visumax 500.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e Additionally, although the femtosecond laser cutting sequence of the Visumax 800 is identical to that of the Visumax 500, there could be differences in long-term changes in clinical results. Another limitation is the small sample size. Studies including larger sample sizes and longer follow-up periods are needed for a more accurate comparison.\u003c/p\u003e \u003cp\u003eThis study showed that the efficacy, safety, and predictability of SMILE procedures are comparable between the Visumax 500 and Visumax 800. However, the lenticule creation time was significantly shorter when using the Visumax 800 versus the Visumax 500, and SMILE with the Visumax 800 was superior to SMILE with the Visumax 500 in terms of centration accuracy and VC induction. These differences might be due to the use of the CentraLign software and the faster repetition rate of the Visumax 800. Further studies are warranted to confirm our findings.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eB.K.K. contributed to the conceptualization, methodology, data collection, writing a manuscript. Y.T.C. provided all technical and material support, and critically revised the manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eB.K.K. had comprehensive access to all data in this study and accepts full responsibility for its integrity and the accuracy of the data analysis.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSekundo, W. et al. Blum M. First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results. \u003cem\u003eJ. Cataract Refract. Surg.\u003c/em\u003e \u003cb\u003e34\u003c/b\u003e, 1513\u0026ndash;1520 (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBlum, M., Lauer, A. S., Kunert, K. S. \u0026amp; Sekundo, W. 10-year results of small incision lenticule extraction. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e35\u003c/b\u003e, 618\u0026ndash;623 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXia, F. et al. Ten-year outcomes following small incision lenticule extraction for up to -10 dioptres myopia. \u003cem\u003eClin. Exp. Optom.\u003c/em\u003e \u003cb\u003e107\u003c/b\u003e, 285\u0026ndash;290 (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAsif, M. I. et al. Complications of small incision lenticule extraction. \u003cem\u003eIndian J. Ophthalmol.\u003c/em\u003e \u003cb\u003e68\u003c/b\u003e, 2711\u0026ndash;2722 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCui, T. et al. Applying machine learning techniques in nomogram prediction and analysis for SMILE treatment. \u003cem\u003eAm. J. Ophthalmol.\u003c/em\u003e \u003cb\u003e210\u003c/b\u003e, 71\u0026ndash;77 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZiebarth, N. M. et al. Surface quality of human corneal lenticules after SMILE assessed using environmental scanning electron microscopy. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e30\u003c/b\u003e, 388\u0026ndash;393 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReinstein, D. Z., Archer, T. J., Potter, J. G., Gupta, R. \u0026amp; Wiltfang, R. Refractive and visual outcomes of SMILE for compound myopic astigmatism with the VISUMAX 800. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e39\u003c/b\u003e, 294\u0026ndash;301 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim, B. K. \u0026amp; Chung, Y. T. Comparison of changes in corneal thickness and curvature after myopia correction between SMILE and FS-LASIK. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e39\u003c/b\u003e, 15\u0026ndash;22 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee, H. et al. Relationship between decentration and induced corneal higher-order aberrations following small-incision lenticule extraction procedure. \u003cem\u003eInvest. Ophthalmol. Vis. Sci.\u003c/em\u003e \u003cb\u003e59\u003c/b\u003e, 2316\u0026ndash;2324 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChan, T. C. Y. et al. Effect of corneal curvature on optical zone decentration and its impact on astigmatism and higher-order aberrations in SMILE and LASIK. \u003cem\u003eGraefes Arch. Clin. Exp. Ophthalmol.\u003c/em\u003e \u003cb\u003e257\u003c/b\u003e, 233\u0026ndash;240 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu, Q. et al. Review on centration, astigmatic axis alignment, pupil size and optical zone in SMILE. \u003cem\u003eAsia Pac. J. Ophthalmol. (Phila)\u003c/em\u003e. \u003cb\u003e8\u003c/b\u003e, 385\u0026ndash;390 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu, M. et al. Decentration of optical zone center and its impact on visual outcomes following SMILE. \u003cem\u003eCornea\u003c/em\u003e \u003cb\u003e34\u003c/b\u003e, 392\u0026ndash;397 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu, S., Zhang, X., You, Z. \u0026amp; Zhou, X. Comparison of the distribution of lenticule decentration following SMILE by pupil center or tear film mark centration. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e36\u003c/b\u003e, 239\u0026ndash;246 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiang, C. \u0026amp; Yan, H. Methods of corneal vertex centration and evaluation of effective optical zone in small incision lenticule extraction. \u003cem\u003eOphthalmic Res.\u003c/em\u003e \u003cb\u003e66\u003c/b\u003e, 717\u0026ndash;726 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePedersen, I. B., Ivarsen, A. \u0026amp; Hjortdal, J. Changes in astigmatism, densitometry, and aberrations after SMILE for low to high myopic astigmatism: A 12-month prospective study. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e33\u003c/b\u003e, 11\u0026ndash;17 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIvarsen, A. \u0026amp; Hjortdal, J. Correction of myopic astigmatism with small incision lenticule extraction. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e30\u003c/b\u003e, 240\u0026ndash;247 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKanellopoulos, A. J. Topography-guided LASIK versus small incision lenticule extraction (SMILE) for myopia and myopic astigmatism: a randomized, prospective, contralateral eye study. \u003cem\u003eJ. Refract. Surg.\u003c/em\u003e \u003cb\u003e33\u003c/b\u003e, 306\u0026ndash;312 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang, J., Zhou, X. \u0026amp; Qian, Y. Decentration following femtosecond laser small incision lenticule extraction (SMILE) in eyes with high astigmatism and its impact on visual quality. \u003cem\u003eBMC Ophthalmol.\u003c/em\u003e \u003cb\u003e19\u003c/b\u003e, 151 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao, P. F. et al. Comparison of correcting myopia and astigmatism with SMILE or FS-LASIK and postoperative higher-order aberrations. \u003cem\u003eInt. J. Ophthalmol.\u003c/em\u003e \u003cb\u003e14\u003c/b\u003e, 523\u0026ndash;528 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLombardo, M. \u0026amp; Lombardo, G. Wave aberration of human eyes and new descriptors of image optical quality and visual performance. \u003cem\u003eJ. Cataract Refract. Surg.\u003c/em\u003e \u003cb\u003e36\u003c/b\u003e, 313\u0026ndash;331 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWong, C. W., Chan, C., Tan, D. \u0026amp; Mehta, J. S. Incidence and management of suction loss in refractive lenticule extraction. \u003cem\u003eJ. Cataract Refract. Surg.\u003c/em\u003e \u003cb\u003e40\u003c/b\u003e, 2002\u0026ndash;2010 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWan, K. H., Lin, T. P. H., Lai, K. H. W., Liu, S. \u0026amp; Lam, D. S. C. Options and results in managing suction loss during small-incision lenticule extraction. \u003cem\u003eJ. Cataract Refract. Surg.\u003c/em\u003e \u003cb\u003e47\u003c/b\u003e, 933\u0026ndash;941 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePradhan, K. R. et al. Quality control outcomes analysis of small-incision lenticule extraction for myopia by a novice surgeon at the first refractive surgery unit in Nepal during the first 2 years of operation. \u003cem\u003eJ. Cataract Refract. Surg.\u003c/em\u003e \u003cb\u003e42\u003c/b\u003e, 267\u0026ndash;274 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOsman, I. M., Awad, R., Shi, W. \u0026amp; Abou Shousha, M. Suction loss during femtosecond laser-assisted small-incision lenticule extraction: Incidence and analysis of risk factors. \u003cem\u003eJ. Cataract Refract. Surg.\u003c/em\u003e \u003cb\u003e42\u003c/b\u003e, 246\u0026ndash;250 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReinstein, D. Z., Archer, T. J., Vida, R. S. \u0026amp; Carp, G. I. Suction stability management in small incision lenticule extraction: incidence and outcomes of suction loss in 4000 consecutive procedures. \u003cem\u003eActa Ophthalmol.\u003c/em\u003e \u003cb\u003e98\u003c/b\u003e, e72\u0026ndash;e80 (2020).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"SMILE, Small incision lenticule extraction, Visumax 800, SMILE Pro","lastPublishedDoi":"10.21203/rs.3.rs-5385801/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5385801/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study compared clinical outcomes between small incision lenticule extraction (SMILE) procedures performed with the Visumax 800 and Visumax 500 femtosecond lasers. We compared the clinical outcomes of 100 eyes of 50 patients who underwent SMILE using the Visumax 800 (SMILE Pro group) and 100 eyes of 50 patients who underwent SMILE using the Visumax 500 femtosecond laser (SMILE group). Outcomes were assessed at a 3-month follow-up, including standard visual outcomes, optic zone decentration, and corneal higher-order aberrations (HOAs). The mean lenticule creation time was significantly shorter in the SMILE Pro group (10.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.82 seconds) than the SMILE group (28.27\u0026thinsp;\u0026plusmn;\u0026thinsp;2.34 seconds, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). At 3 months postoperatively, the groups had no significant differences in uncorrected or corrected distance visual acuity, residual refractive errors, or corneal HOAs. However, the optic zone decentration was significantly smaller in the SMILE Pro group than in the SMILE group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the vertical coma induction was significantly lower in the SMILE Pro group compared with the SMILE group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.034), suggesting that the Visumax 800 provides enhanced centration accuracy, reduced vertical coma induction, and faster lenticule creation, demonstrating comparable efficacy, safety, and predictability to the Visumax 500.\u003c/p\u003e","manuscriptTitle":"Comparison of clinical outcomes following small incision lenticule extraction performed with the Visumax 800 versus Visumax 500 femtosecond laser","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-19 10:51:15","doi":"10.21203/rs.3.rs-5385801/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-03-17T13:38:36+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-16T20:34:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-02-28T16:31:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"31664146255986540401949465430789525565","date":"2025-02-26T10:09:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"49244680051825609974828229099537438464","date":"2025-02-20T05:35:33+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-02-19T10:26:50+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-02-06T10:53:17+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-11-18T11:11:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-11-16T05:47:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-11-04T07:33:31+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"77fad875-2a0d-489c-9d09-1bc9805929d8","owner":[],"postedDate":"December 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":41500357,"name":"Health sciences/Diseases/Eye diseases/Refractive errors"},{"id":41500358,"name":"Health sciences/Diseases/Eye diseases/Vision disorders"}],"tags":[],"updatedAt":"2025-07-21T16:04:37+00:00","versionOfRecord":{"articleIdentity":"rs-5385801","link":"https://doi.org/10.1038/s41598-025-98041-9","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-07-15 15:57:27","publishedOnDateReadable":"July 15th, 2025"},"versionCreatedAt":"2024-12-19 10:51:15","video":"","vorDoi":"10.1038/s41598-025-98041-9","vorDoiUrl":"https://doi.org/10.1038/s41598-025-98041-9","workflowStages":[]},"version":"v1","identity":"rs-5385801","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5385801","identity":"rs-5385801","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}