Background: To investigate the safety and optical quality of small-incision lenticule extraction (SMILE) combined with monovision, and patient satisfaction with the procedure. Methods: The present study assessed a non-random case series involving 60 eyes of 30 patients (mean age 45.53 ± 3.20 years [range 41 to 52 years]) treated bilaterally using the VisuMax 500 system (Carl Zeiss Meditec, Jena, Germany) between January and July 2016. The target refraction was plano for the distance eye, and between − 0.5 and − 1.75 diopters (D) for the near eye. Visual acuity, refraction errors, ocular aberrations, and satisfaction questionnaire scores were calculated 1 year after surgery. Results: All surgeries were uneventful, with a mean safety index of 1.03 and 1.04 in dominant and nondominant eyes, respectively. Binocular uncorrected distance visual acuity of all patients was ≥20/32, while binocular uncorrected near visual acuity was ≥20/40 1 year postoperatively. Higher-order aberration (0.45 ± 0.14, 0.51 ± 0.15 μm), spherical (0.18 ± 0.15, 0.21 ± 0.14 μm) and coma aberration (0.31 ± 0.16, 0.27 ± 0.17 μm) were identical between dominant and nondominant eyes after surgery. The overall satisfaction rate was 86.7% (26/30), with large contributions from age (OR = 1.76 95% CI: 1.03–2.53; P = 0.036). Binocular uncorrected distance visual acuity was related to preoperative spherical diopter (r = − 0.500; P =0.005). Conclusions: Monovision appears to be a safe and effective option for myopia patients with presbyopia who are considering the SMILE procedure. Patients with younger age were more satisfied with the procedure. Keywords: Monovision, SMILE, Presbyopia, Safety, Satisfaction Background challenge for refractive surgeons. In recent years, refract- Presbyopia refers to an impairment of near vision that is ive surgeries combined with monovision have emerged common among adults > 40 years of age, resulting from as an alternative for compensation of presbyopia, and declined amplitude of accommodation . Currently, was proven to be effective in conductive keratoplasty several surgical methods are used to correct presbyopia, and laser in situ keratomileusis [3, 4]. This strategy aims including the excimer laser procedure, conductive to give patients both near and distance vision without keratoplasty, intrastromal femtosecond ring incisions, glasses. It is not as invasive as multifocal intraocular and pseudophakic multifocal intraocular lens . Each changes , and more convenient than contact lens cor- procedure has advantages and disadvantages; neverthe- rection. However, reduced contrast sensitivity, reduced less, surgical correction of presbyopia remains a major stereopsis, and small-angle esotropic shift associated with monovision correction were reported to be com- promises after surgery . * Correspondence: email@example.com With advances in refractive surgery technology, small Dan Fu and Li Zeng as equal first authors. Dan Fu and Li Zeng are contributed equally to this work. incision lenticule extraction (SMILE) is becoming more Department of Ophthalmology, Eye and ENT Hospital, Fudan University, prevalent due to its excellent safety, efficiency, and good Shanghai, China preservation of corneal biomechanics [6, 7]. To the best NHC Key Laboratory of Myopia (Fudan University), No. 83 FenYang Road, Shanghai 200031, People’s Republic of China © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Fu et al. BMC Ophthalmology (2018) 18:131 Page 2 of 5 of our knowledge, however, few reports have described graded on 4 levels: 0 indicated no discomfort whatso- visual outcomes of monovision induced by SMILE in my- ever; 1 indicated discomfort occasionally occurred but opic patients with presbyopia . Accordingly, we exam- did not influence life; 2 indicated discomfort, and usually ined monovision combined with SMILE to investigate its influenced daily life; and 3 indicated discomfort that was efficacy, safety, and patient satisfaction over a long-term too serious to tolerate. At the end of the questionnaire, follow-up period. patients were asked to grade overall satisfaction on a scale between 0 and 10, in which 0 indicated not satis- Methods fied at all and 10 indicated extremely satisfied. The present study was a non-comparative case series, and The surgical procedure was similar to the standard was approved by the Ethics Committee of the Eye and SMILE treatments described by the authors in a previ- ENT Hospital of Fudan University (Shanghai, China) and ous study . The dominant eye was corrected for dis- a written informed consent from each patient was tance and the nondominant eye for near, with target obtained before surgery as a standard protocol preopera- ranging from − 0.5 D to − 1.75 D,. Preoperatively, we tively. All procedures were adhered to Declaration of used glasses to simulate target refractive status, with bin- Helsinki. Patients who underwent bilateral SMILE ocular distance visual acuity ≥20/32(the residual myopia (performed by the same surgeon [ZX]) between January in the nondominant eye is –X for instance). If X ≥ and July 2016, with available 1-year follow-up data, were adding power (A), then residual myopia is set to be –A; reviewed. A total of 30 patients (10 male; mean age 45.53 if X ≤ A, then residual myopia is set to be –X. The over- ± 3.20 years [range, 41 to 52 years]) were enrolled. The all purpose of this design was to ensure good postopera- cohort had a mean preoperative spherical diopter (D) of − tive UDVA with increasing near visual acuity as much as 6.12 ± 2.39 D (− 1.5 to − 10 D), cylinder of − 0.79 ± 0.62 D possible. Thus, we considered preoperative presbyopia (− 3.0 to 0 D), binocular uncorrected near visual acuity degree only and no preventive amount of residual my- ranging from 20/32 to 20/20, and add 0.85 ± 0.56 D opia was added into design. This principle is derived (0 to 2.25 D). from years of surgical l experience, though individual Inclusion criteria were as follows: ≥40 years of age; best cases will be adjusted according to the needs of life. corrected visual acuity ≥20/20 in either eye; spherical Statistical analysis was performed using SPSS version diopter ≤− 10.0 D; add > 0 D; and cylinder ≤− 3.0D. 22.0 (IBM Corporation, Armonk, NY, USA), and all data Exclusion criteria included severe eye comorbidities such are presented as mean ± SD. Visual acuity data are in as diabetic retinopathy, age-related macular degeneration, LogMAR units. The paired t test was performed to com- cataract causing visual impairment, or glaucoma with sig- pare root mean square (RMS) differences in ocular aberra- nificant field loss, and a history of severe amblyopia or tion, and the Wilcoxon signed-rank test was performed to strabismus. compare safety indexes, which were nonlinear values be- Regular preoperative examinations, including cyclople- tween the dominant and nondominant eye. For satisfac- gic refraction, corrected visual acuity, slit-lamp examin- tion was subjectively graded on 4 ordered levels, orderly ation, corneal topography (Pentacam, Oculus Optikgerate, regression analysis was used to detect factors affecting sat- Wetzlar, Germany), ocular aberration (WASCA wavefront isfaction. Factors included in this analysis are age, sex, and analyzer, Carl Zeiss Meditec, Jena, Germany), and fundus preoperative spherical equivalent, which are independent examination were performed. The dominant eye was de- variables.Spearman’s test was used to determine relation- termined using the “hole test” . Patient was asked to ships between visual acuity and other parameters; P <0.05 align a dot 4 m away through a 1″ diameter hole in a A4 was considered to be statistically significant. sheet of paper, held at arm length. Two eyes were covered in turn, and the eye with which the dot appeared most centered was regarded as the dominant eye. The proce- Results dures above repeated at least 3 times until the result was All surgeries were uneventful, with no intraoperative or the same for at least 2 times consecutively. postoperative complications. The mean safety index was The 1-year examinations typically included manifest 1.03 and 1.04 (P > 0.05) in the dominant and nondomi- refraction, assessments of monocular and binocular un- nant eye, respectively. In the dominant eyes, the percent- corrected distance visual acuity (UDVA) (at 4 m), uncor- age of UDVA ≥20/32 were 96.7%; in the nondominant rected neat visual acuity (UNVA) (at 33 cm) and eyes, the percentage of UDVA ≥20/40 was 76.7%. corrected distance visual acuity (CDVA) under the same Predictability and accuracy are presented in Fig. 1. illumination. In addition, we constructed a questionnaire As shown in Figs. 2, 93.3% of the nondominant eyes considering patient satisfaction including spectacle de- achieved UNVA ≥20/40, while 76.7% of the dominant pendence for daily activities, halo, glare, visual fatigue, eyes achieved UNVA ≥20/40. Binocular near visual acu- dry eye, and overall satisfaction . Each question was ity ≥20/40 was achieved in all patients. Fu et al. BMC Ophthalmology (2018) 18:131 Page 3 of 5 Fig. 1 Refractive outcomes after small incision lenticule extraction combined with monovision. a Uncorrected Distance Visual Acuity. b Changes in Corrected Distance Visual Acuity. c Spherical Equivalent Attempted vs Achieved. d Spherical Equivalent Refractive vs Accuracy Ocular aberrations in both eyes are summarized in related to the satisfaction, while sex (P =0.67) was Table 1. Compared with preoperative values, the RMS of not significant. total high-order aberration (HOA) and spherical aberration Spearman’s test revealed that preoperative spherical D were not different postoperatively. Coma increased signifi- was related to postoperative binocular UDVA (r = − 0.500; cantly after surgery (0.17 ± 0.10, 0.29 ± 0.17; P < 0.001) P =0.005). (60 eyes). Results of the satisfaction survey revealed that 63.3, Discussion 6.7, and 3.3% patients experienced mild, moderate, and Monovision excimer laser correction has a consider- severe halo, respectively; 86.7% patients complained of able history in photorefractive keratectomy and dry eye, of which 69.2% was mild dry eye. Three patients laser-assisted in situ keratomileusis (LASIK), although still required reading glasses occasionally, and 6 required various degrees of satisfaction have been reported in glasses when driving. The completely “glasses-off” rate previous studies [9, 10]. With the advantages of was 76.7%. The mean satisfaction score was 8.32 ± 1.27 SMILE highlighted, making use of SMILE combined (range 5 to 10). with monovision has become a new treatment option In orderly regression analysis, age, and sex consti- for individuals with presbyopia. However, few studies tutes a significant mode (P = 0.02). On that premise, have investigated the results of SMILE combined with age (OR = 1.76; 95% CI: 1.03–2.53; P = 0.036) was monovision. Fig. 2 Near visual acuity after small lenticule extraction combined with monovision Fu et al. BMC Ophthalmology (2018) 18:131 Page 4 of 5 Table 1 Ocular aberration in dominant and nondominant eyes before and after surgery (μm) Preoperative (6 mm) Postoperative (6 mm) P Dominant Nondominant P Dominant Nondominant P HOA 0.39 ± 0.11 0.41 ± 0.33 0.896 0.45 ± 0.14 0.51 ± 0.15 0.079 0.542 SA 0.15 ± 0.07 0.12 ± 0.07 0.468 0.18 ± 0.15 0.21 ± 0.14 0.092 0.231 Coma 0.17 ± 0.10 0.13 ± 0.11 0.149 0.31 ± 0.16 0.27 ± 0.17 0.317 < 0.001 HOA higher-order aberration, SA spherical aberration Paired t test between preoperative and postoperative values In our study, the mean safety index was 1.04 and 1.03 HOA and spherical aberration may result over a long in the dominant and nondominant eye, respectively, with period. Differences between the dominant and nondo- no statistically significant differences found between minant eyes were not found. A previous study reported eyes. The percentage of remaining or gained BCVA was that higher myopia errors possibly led to an increase in 83.3 and 86.7% in the dominant and nondominant eyes, postoperative coma . Regardless of target myopia in respectively. This result is consistent with previous the nondominant eye, we found that the minor mono- SMILE results [7, 11]. Levinger et al.  studied pa- vision would not induce unbalanced ocular aberration in tients ≥40 years of age, and found that BCVA was un- both eyes, which may have contributed to postoperative changed at the 1-year follow-up. Both LAISIK and satisfaction. SMILE were demonstrated efficient in presbyopia treat- The satisfaction rate in this study was 86.7%, which is ment, though less studies about SMILE monovision are different from that of contact lens with monovision, reported . SMILE owes the advantage of smaller inci- which ranged from 60 to 80% in a previous study,  sion and less flap-related complication . Accordingly, and also different from the 96% satisfaction with the visual quality was reported better after SMILE than LASIK-induced monovision reported in the study by LASIK, such as ocular aberration and contrast sensitivity Goldberg et al. . Further questioning of the unsatis- . The difference between surgeries may partly ac- fied patients revealed the following reasons for dissatis- count for the various postoperative results and subject- faction: difficulty with night driving; visual fatigue when ive feelings, however, direct comparison is unavailable reading; and reduction in distance acuity. Unlike LASIK for different criteria. monovision, SMILE lacks the induction of spherical ab- All patients in this study achieved a binocular UDVA erration to enhance depth of field. Though near vision is ≥20/32, and the percentage of binocular UDVA ≥20/25 acceptable in current study, the improvement of near was 76.7%, which was a significant improvement from vison is not so obvious as the improvement of distance preoperative values. In terms of binocular UNVA, 100% of vision for myopic patients. Besides, the target refraction patients achieved UNVA ≥20/40, and the percentage of for the nondominant eye ranges from − 0.5 D to − 1.75 D, patients with UNVA ≥20/25 was 83.3%. Accordingly, considering anisometropia tolerance for most patients. SMILE combined with monovision was effective in both Consistent with the recommendation offered by far and near vision. Similar results were also found in the Wright et al.  we are cautious about target refrac- study by Goldberg et al. , in which 79% of patients tions > − 2.0 D to avoid integration difficulties. Barisic achieved UDVA ≥20/25, and 87.7% of patients achieved et al.  found that − 0.5 D to − 1.25 D was suitable for UNVA of J1 or better. However, a retreatment rate of presbyopic individuals < 50 years of age. Although most 13.2% was reported in their study, and 5 nondominant individuals are satisfied with this surgery, patient selection eyes were retreated to enhance distance visual acuity. and information are critical to optimize monovision de- Although no patient requested retreatment in our study, signs and warrant further study. distance vision loss remains a forfeit in most cases with Although age has been considered to be unrelated to monovision. Garcia-Gonzalez et al.  reported a loss in the success of monovision,  we found that younger UDVA after LASIK-induced monovision. One patient in individuals in the present study expressed higher satis- our study was dissatisfied with this surgery due to diffi- faction after surgery. Correspondingly, patients with culty with night driving . We speculate that interocu- early presbyopia were more satisfied. Relatively abundant lar blur suppression is less effective at night and this may accommodation reserve is helpful in acceptable UNVA. be a source of postoperative dissatisfaction. Given less surgery-induced anisometropia, patients with Spherical aberration and HOA were unchanged after less severe presbyopia may have better optical quality surgery, while coma increased significantly. Ocular was based on a previous study . Patients with higher pre- usually associated with postoperative glare and halo. It operative spherical diopters tended to experience worse has been reported that SMILE-induced aberration can binocular UDVA postoperatively. Kim et al.  com- be restored over a long period . Therefore, unchanged pared the efficacy of SMILE between subjects with high Fu et al. BMC Ophthalmology (2018) 18:131 Page 5 of 5 and mild-moderate myopia, and reported that a lower 3. Barisic A, Gabric N, Dekaris I, Romac I, Bohac M, Juric B. Comparison of different presbyopia treatments: refractive lens exchange with multifocal percentage of patients achieved UDVA ≥20/20 in the intraocular lens implantation versus LASIK monovision. Coll Antropol. 2010; high-myopia group 1-year postoperatively. Coinciden- 34(Suppl 2):95–8. tally, worse predictability, efficacy and spherical aberra- 4. Wyzinski P. Why are refractive surgeons still wearing glasses? Ophthalmic Surg. 1987;18(5):349–51. tion were found in highly myopic patients in the study 5. Hayashi K, Ogawa S, Manabe S, Yoshimura K. Binocular visual function of by Jin et al. . modified pseudophakic monovision. Am J Ophthalmol. 2015;159(2):232–40. One limitation of the present study was the lack of a 6. Miao H, Tian M, Xu Y, Chen Y, Zhou X. Visual outcomes and optical quality after femtosecond laser small incision Lenticule extraction: an 18-month control group and, given the relatively small sample size, prospective study. J Refract Surg. 2015;31(11):726–31. it was difficult to make comparisons between subgroups. 7. Vestergaard AH, Grauslund J, Ivarsen AR, Hjortdal JO. Efficacy, safety, Further comparison between groups stratified according predictability, contrast sensitivity, and aberrations after femtosecond laser lenticule extraction. J Cataract Refract Surg. 2014;40(3):403–11. to different target refraction or sex would be interesting 8. Luft N, Siedlecki J, Sekundo W, Wertheimer C, Kreutzer TC, Mayer WJ, areas of investigation. Furthermore, we only analyzed Priglinger SG, Dirisamer M. Small incision lenticule extraction (SMILE) data 1-year postoperatively, and consecutive observation monovision for presbyopia correction. Eur J Ophthalmol. 2018;28(3):287–93. 9. Reinstein DZ, Archer TJ, Gobbe M. LASIK for myopic astigmatism and would be helpful to further understand the adaption presbyopia using non-linear aspheric micro-Monovision with the Carl Zeiss period of these patients. Meditec MEL 80 platform. J Refract Surg. 2011;27(1):23–37. 10. Levinger E, Trivizki O, Pokroy R, Levartovsky S, Sholohov G, Levinger S. Monovision surgery in myopic presbyopes: visual function and satisfaction. Conclusions Optom Vis Sci. 2013;90(10):1092–7. In conclusion, SMILE combined with monovision ap- 11. Xu Y, Yang Y. Small-incision lenticule extraction for myopia: results of a peared to be safe and effective in a population of presby- 12-month prospective study. Optom Vis Sci. 2015;92(1):123–31. 12. Arba-Mosquera S, de Ortueta D. Geometrical analysis of the loss of ablation opic patients. Patients with younger agewere more efficiency at non-normal incidence. Opt Express. 2008;16(6):3877–95. satisfied with the procedure. 13. Fau GS, Gupta R. Comparison of visual and refractive outcomes following femtosecond laser- assisted lasik with smile in patients with myopia or Abbreviations myopic astigmatism. J Refrac Surg. 2014;30(9):590–6. CDVA: Corrected distance visual acuity; LASIK: Laser-assisted in situ keratomileusis; 14. Goldberg DB. Laser in situ keratomileusis monovision. J Cataract Refract SMILE: Small incision lenticule extraction; UDVA: Uncorrected distance visual Surg. 2001;27(9):1449–55. acuity; UNVA: Uncorrected near visual acuity 15. Garcia-Gonzalez M, Teus MA, Hernandez-Verdejo JL. Visual outcomes of LASIK-induced monovision in myopic patients with presbyopia. Am J Funding Ophthalmol. 2010;150(3):381–6. National Natural Science Foundation of China (Grant No. 81570879). 16. Chu BS, Wood JM, Collins MJ. Effect of presbyopic vision corrections on Natural Science Foundation of Shanghai (Grant No. 17140902900). perceptions of driving difficulty. Eye Contact Lens. 2009;35(3):133–43. National Natural Science Foundation of China for Young Scholars (Grant No. 17. Pedersen IB, Ivarsen A, Hjortdal J. Three-year results of small incision 81600762). lenticule extraction for high myopia: refractive outcomes and aberrations. J Refract Surg. 2015;31(11):719–24. Availability of data and materials 18. de Castro LE, Sandoval HP, Bartholomew LR, Vroman DT, Solomon KD. The datasets during and/or analyzed the current study are available upon High-order aberrations and preoperative associated factors. Acta request from the co-first authors Dan Fu and Li Zeng. Ophthalmol Scand. 2007;85(1):106–10. 19. Jain S, Arora I, Azar DT. Success of monovision in presbyopes: review of the Authors’ contributions literature and potential applications to refractive surgery. Surv Ophthalmol. FD and ZL drafted the manuscript and performed the literature. ZJ participated 1996;40(6):491–9. in information gathering and editing. MHM, YZQ and ZXT conceived the idea 20. Wright KW, Guemes A, Kapadia MS, Wilson SE. Binocular function and and supervised writing of this paper/ All authors read and approved the final patient satisfaction after monovision induced by myopic photorefractive manuscript. keratectomy. J Cataract Refract Surg. 1999;25(2):177–82. 21. Jain S, Ou R, Azar DT. Monovision outcomes in presbyopic individuals after Ethics approval and consent to participate refractive surgery. Ophthalmology. 2001;108(8):1430–3. This study was performed in accordance with the Declaration of Helsinki and 22. Kim JR, Kim BK, Mun SJ, Chung YT, Kim HS. One-year outcomes of small- was approved by the Ethics Committee of the Eye and ENT Hospital, Shanghai, incision lenticule extraction (SMILE): mild to moderate myopia vs. high China. Written informed consent was obtained from all subjects after the aims myopia. BMC Ophthalmol. 2015;15:59. and nature of the study were explained to the participants. 23. Jin HY, Wan T, Wu F, Yao K. Comparison of visual results and higher-order aberrations after small incision lenticule extraction (SMILE): high myopia vs. Competing interests mild to moderate myopia. BMC Ophthalmol. 2017;17(1):118. The authors declare that they have no competing interests. Publisher’sNote Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Received: 12 January 2018 Accepted: 22 May 2018 References 1. Patel I, West SK. Presbyopia: prevalence, impact, and interventions. Community Eye Health. 2007;20(63):40–1. 2. Gil-Cazorla R, Shah S, Naroo SA. A review of the surgical options for the correction of presbyopia. Br J Ophthalmol. 2016;100(1):62–70.
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Published: May 31, 2018