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Huang Y, Zhan B, Han T, Zhou X. Effective optical zone following small incision lenticule extraction: a review. Graefes Arch Clin Exp Ophthalmol 2024; 262:1657-1665. [PMID: 37851133 DOI: 10.1007/s00417-023-06263-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/18/2023] [Accepted: 10/01/2023] [Indexed: 10/19/2023] Open
Abstract
Small incision lenticule extraction (SMILE) is a "flapless" keratorefractive surgery with excellent safety, efficacy, stability, and predictability for myopia correction. A recent global multicenter study also reported good refractive outcomes for hyperopic SMILE. SMILE has shown advantages including improved biomechanical strength, fewer dry eye symptoms, less corneal denervation, and fewer surgery-induced higher-order aberrations over laser in situ keratomileusis (LASIK). However, night vision complaints, including glare, halos, and starbursts, could still occur after SMILE. These symptoms have been proven to be closely related to the effective optical zone (EOZ), which is defined as the achieved area of corneal ablation. A larger postoperative EOZ may indicate better visual quality, making EOZ an important safety parameter for keratorefractive surgeries. As SMILE has gained wider application globally, the EOZ following SMILE has also been increasingly studied in the field of refractive surgery. This review provides an update on topics related to the EOZ after SMILE, including its measurement and influencing factors, aiming to benefit the personalization of the surgical algorithm and ultimately improve the visual quality after the SMILE procedure.
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Affiliation(s)
- Yangyi Huang
- Eye Institute and Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- NHC Key Laboratory of Myopia Fudan University Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care, Shanghai, China
| | - Biyun Zhan
- Eye Institute and Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China
- NHC Key Laboratory of Myopia Fudan University Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care, Shanghai, China
| | - Tian Han
- Eye Institute and Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China.
- NHC Key Laboratory of Myopia Fudan University Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care, Shanghai, China.
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, No.19 Baoqing Road, Xuhui District, Shanghai, 200031, China.
- NHC Key Laboratory of Myopia Fudan University Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care, Shanghai, China.
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Liu S, Liu J, Cheng C, Cai Y, Huang Y, Han T, Xiao Y, Zhou X. Effective Optical Zone and Centration Following SMILE and FS-LASIK for High Myopia Calculated With a Novel Method. J Refract Surg 2023; 39:736-740. [PMID: 37937758 DOI: 10.3928/1081597x-20230822-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
PURPOSE To compare the effective optical zone (EOZ) and centration in eyes with high myopia after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) using a novel method. METHODS Forty eyes of 40 consecutive patients with high myopia scheduled for SMILE or FS-LASIK were enrolled in the study. The EOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then analyzed and compared between the two procedures 6 months after surgery. RESULTS The mean EOZ diameter for SMILE (4.41 ± 0.14 mm) was larger than that for FS-LASIK (4.24 ± 0.28 mm; P = .002), corresponding to reductions of 1.60 ± 0.11 and 1.71 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) (P = .007). Moreover, the total decentration for SMILE (0.33 ± 0.12 mm) was greater than that for FS-LASIK (0.27 ± 0.15 mm; P = .020). The induction of spherical aberration (SA) was lower with SMILE than with FS-LASIK (P = .007). CONCLUSIONS A larger EOZ and less SA were observed after SMILE than after FS-LASIK in eyes with high myopia. [J Refract Surg. 2023;39(11):736-740.].
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Moshirfar M, Herron MS, Cha DS, Santos J, Payne CJ, Hoopes PC. Comparing Effective Optical Zones After Myopic Ablation Between LASIK, PRK, and SMILE With Correlation to Higher Order Aberrations. J Refract Surg 2023; 39:741-750. [PMID: 37937754 DOI: 10.3928/1081597x-20231016-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
PURPOSE To explore size, decentration, and eccentricity of effective optical zones (EOZs) in laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE) and correlate them to higher order aberrations (HOAs). METHODS This was a retrospective chart review of 188 eyes that underwent refractive surgery for compound myopia (61 LASIK, 84 PRK, 43 SMILE). EOZ measurements were determined using 1-year postoperative Pentacam (Oculus Optikgeräte GmbH) tangential difference maps. HOA data were measured using Pentacam wavefront aberration Zernike polynomials. Correlations between EOZs and HOAs were analyzed. RESULTS The EOZs of LASIK and PRK are smaller than SMILE at 19.54 ± 1.44, 19.39 ± 1.66, and 22.18 ± 2.61 mm2, respectively (P < .001). No difference existed in absolute decentration from corneal vertex (P = .078) or pupil center (P = .131), but horizontal and vertical components differed significantly (P < .001). Smaller EOZ areas were correlated with greater spherical aberration induction (rLASIK = -0.378, rPRK = -0.555, rSMILE = -0.501) and total HOA induction in all groups. Absolute decentration from corneal vertex positively correlated with total HOA (rLASIK = 0.396, rPRK = 0.463, rSMILE = 0.399) and directional vertical coma induction negatively correlated with vertical decentration from the corneal vertex (rLASIK = -0.776, rPRK = -0.665, rSMILE = -0.576) in all groups. CONCLUSIONS SMILE results in a larger EOZ than LASIK and PRK, and absolute decentration remains comparable regardless of surgical reference center, despite horizontal/vertical differences. Surgical planning to ensure adequate EOZ size and centration may reduce induction of HOAs, including spherical aberrations and vertical coma. [J Refract Surg. 2023;39(11):741-750.].
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Saad A, Steinberg J, Frings A. Repeatability of pupil diameter measurements using three different topography devices. PLoS One 2023; 18:e0290417. [PMID: 37594948 PMCID: PMC10437858 DOI: 10.1371/journal.pone.0290417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 08/07/2023] [Indexed: 08/20/2023] Open
Abstract
PURPOSE To evaluate the intra- and inter-device repeatability of pupil diameter measurements using three different devices in patients prior to corneal refractive surgery. METHODS We examined preoperative measurements from a total of 204 eyes (102 patients) scheduled for corneal refractive surgery at two private centers between July and December 2021. Three consecutive scans were performed with three different devices (Sirius anterior segment analyzer, Pentacam HR, IOLMaster 500) in the same session by the same examiner under standardized conditions. To assess the intra- and inter-device repeatability, we calculated the Intraclass Correlation Coefficient (ICC) and demonstrated results using Bland-Altman plots. RESULTS The measurement accuracy (intra-device repeatability) of Sirius and IOLMaster was comparable (ICC = 0.64 and 0.61, respectively), with almost no statistically significant differences. Sirius showed the highest measurement accuracy among the three devices. Pentacam measurements resulted in lower precision, with an ICC of 0.09. The agreement between the pairs of devices (inter-device repeatability) was low (wide LoA ranges, Table 5). CONCLUSION In this study, the intra-device repeatability of Sirius and IOLMaster was higher than that of the Pentacam, although it did not achieve an optimal level across all three devices. The three devices examined cannot be used interchangeably.
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Affiliation(s)
- Amr Saad
- Department of Ophthalmology, University Hospital of Duesseldorf, Duesseldorf, Germany
| | - Johannes Steinberg
- Department of Ophthalmology, University Medical Center, Hamburg, Germany
- Zentrum Sehstärke, Hamburg, Germany
| | - Andreas Frings
- Department of Ophthalmology, University Hospital of Duesseldorf, Duesseldorf, Germany
- Augenheilkunde & Augenlaser Zentrum PD Dr. med. A. Frings, Nuremberg, Germany
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Ladi JS, Gaikwad A, Shah NA. Comparative study of small incision refractive lenticule extraction with 5 mm versus 6.5 mm optic zone for myopia. Indian J Ophthalmol 2023; 71:2717-2721. [PMID: 37417110 PMCID: PMC10491035 DOI: 10.4103/ijo.ijo_2559_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 03/31/2023] [Accepted: 04/05/2023] [Indexed: 07/08/2023] Open
Abstract
Purpose To compare residual stromal thickness (RST) in eyes undergoing small incision refractive lenticule extraction (SMILE) using a lenticular diameter of 6.5 mm versus those with a diameter of 5 mm. Methods: In this retrospective comparative case series. , consecutive patients who underwent SMILE between 2016 and 2021 with at least 6 months of follow-up were included. Preoperative best-corrected distance visual acuity (BCDVA), refractive error, contrast sensitivity, central corneal thickness, keratometry, higher order aberrations, and scotopic pupil size were recorded using a Placido disk topography with Sheimpflug tomography-based system. Patients underwent SMILE with a lenticular diameter of 6.5 mm until 2018 (n = 372 eyes). Thereafter, the lenticular diameter was reduced to 5 mm (n = 318). The RST, postoperative refraction, aberrations, subjective glare, and halos were compared across groups at 1 and 6 months. Results The mean age of participants was 26.8 ± 5.8 years with a mean preoperative spherical equivalent of -4.48 D ± 2.16 D (range: -0.75 to -12.25 D) and mean scotopic pupil of 3.7 ± 0.75 mm. Eyes in the 5 mm group had 30.6 m (95% confidence interval [CI] = 28 to 33 m, P < 0.001) greater RST compared to the 6.5 mm group after adjusting for spherical equivalent and preoperative pachymetry. There were no differences in vision, contrast sensitivity, aberrations (wavefront error of 0.19 ± 0.2 vs. 0.25 ± 0.2, P = 0.19) or glare between the two groups. Conclusion SMILE performed with a lenticular diameter of 5 mm leads to greater RST across the myopic range, but without inducing significant higher-order aberrations.
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Affiliation(s)
- Jeevan S Ladi
- Department of Ophthalmology, Dada Laser Eye Institute, Pune, Maharashtra, India
| | - Anita Gaikwad
- Department of Ophthalmology, Dada Laser Eye Institute, Pune, Maharashtra, India
| | - Nitant A Shah
- Department of Ophthalmology, Dada Laser Eye Institute, Pune, Maharashtra, India
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Liang C, Yan H. Methods of Corneal Vertex Centration and Evaluation of Effective Optical Zone in Small Incision Lenticule Extraction. Ophthalmic Res 2023; 66:717-726. [PMID: 36917962 DOI: 10.1159/000529922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 02/20/2023] [Indexed: 03/16/2023]
Abstract
Inappropriate small incision lenticule extraction (SMILE) centration methods can affect the decentration of the effective optical zone (EOZ) after operation, which can subsequently lead to the decline of postoperative visual quality. We aimed to provide an overview of corneal vertex (CV) centration methods and an evaluation of the size and decentration of the EOZ in SMILE. We described the CV centration methods for patients with myopia, myopic astigmatism, hyperopia, and large kappa angle. The measurement methods of the EOZ were evaluated from the aspects of corneal morphology and corneal refractive power. Additionally, we summarized the advantages and disadvantages of measuring decentration based on topographic mapping and intraoperative video-captured images. Finally, we discussed the relationship between the EOZ and visual quality. Based on our review, clinicians should consider the following when choosing CV centration methods and evaluating EOZ postoperatively. First, the tear film mark center or topographic map comparison method is preferred for the correction of myopia, low myopic astigmatism, hyperopia, and large kappa angle (>0.2 mm). Triple marking centration is recommended for high myopic astigmatism (-3.5 diopters). Second, the total corneal power better reflects the change in refractive power than the topographic method. The measurement of the area rather than the diameter of the total corneal refractive power is more suitable for the evaluation of noncircular EOZs after high myopia astigmatism (<-2.0 diopters). Third, for the evaluation of decentration, the tangential curvature difference map method is preferred as it is not influenced by offset pupils. Finally, a large EOZ after SMILE may improve patient tolerance to decentration.
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Affiliation(s)
- Chen Liang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China,
- Department of Ophthalmology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China,
| | - Hong Yan
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, China
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Wang X, Xia L. Evaluation of the Effects of Myopic Astigmatism Correction and Anterior Corneal Curvature on Functional Optical Zone After SMILE. J Refract Surg 2023; 39:135-141. [PMID: 36779466 DOI: 10.3928/1081597x-20221215-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
PURPOSE To evaluate the influence of different degrees of myopic astigmatism correction and preoperative anterior corneal curvature on the functional optical zone (FOZ) following small incision lenticule extraction (SMILE). METHODS In this retrospective study, 68 patients (106 eyes) treated with SMILE were grouped according to myopic astigmatism correction: control (0.00 diopters [D]), moderate astigmatism (-0.50 to -2.00 D), and high astigmatism (> -2.00 D). The FOZ was measured and compared between the three groups for 3 months. Correlations between attempted correction, anterior corneal curvature, corneal aberrations, and the FOZ were analyzed. RESULTS The preoperative mean treatment spherical equivalent was comparable among the three groups. The average FOZ was 5.06 ± 0.24 mm in the control group, 5.19 ± 0.25 mm in the moderate astigmatism group, and 5.35 ± 0.20 mm in the high astigmatism group The FOZ showed statistically significant differences among the three groups (P < .001), particularly between the high astigmatism group and the other two groups (P < .001 and .018). Correlation analysis showed that the total higher order aberrations, coma, and spherical aberration change were correlated with the FOZ (P < .001). Preoperative steep keratometry, average keratometry, and corneal astigmatism were significantly correlated with the FOZ (P < .05). The correlation remained after excluding the influence of attempted correction on the FOZ (P < .05). After adjusting for other risk factors using multiple linear regression analysis, there was still a significant positive association between preoperative steep keratometry and the FOZ (P < .001). CONCLUSIONS Patients with higher myopic astigmatism achieved a larger FOZ and less induced horizontal coma than the control and moderate astigmatism groups. A larger FOZ after SMILE can be achieved in eyes with steeper keratometry. [J Refract Surg. 2023;39(2):135-141.].
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Mao X, Ji S, Chen H, Dai J. Comparison of Postoperative Safety, Efficacy, and Visual Quality after SMILE for Myopic Patients with Different Corneal Thicknesses. Curr Eye Res 2023; 48:18-24. [PMID: 36285731 DOI: 10.1080/02713683.2022.2117382] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE To investigate the safety, efficacy, and visual quality of small incision lenticule extraction (SMILE) in different corneal thickness patients with myopia or myopic astigmatism. METHODS This prospective cohort study included 191 right eyes of 191 patients. Eyes were divided into three groups according to preoperative central corneal thickness (CCT) (Preoperative central corneal thickness (CCT) was the group indicator.) There were 31 eyes in the thin cornea group (CCT ≤500 um (μm), TC), 94 eyes in the moderate corneal thickness group (CCT ≥501 um (μm) and ≤550 um (μm), MD) and 66 eyes in the thick cornea group (CCT ≥550 um (μm), TK). Comparisons in uncorrected (UDVA) and best-corrected distance visual acuity (BDVA), manifest refractive spherical equivalent (SE), preoperative mesopic/photopic contrast sensitivity (CS), ocular higher-order aberrations (HOAs) at a 6mm analytical pupil diameter, and visual quality questionnaires were made (performed) among the three groups during the postoperative six months. Subgroup analyses were made based on preoperative SE. RESULTS The safety indices at six months were 1.15 ± 0.18, 1.14 ± 0.17, and 1.18 ± 0.17, respectively (p = 0.374), and the efficacy indices at six months were 1.07 ± 0.25, 1.12 ± 0.22, and 1.11 ± 0.21, respectively (p = 0.599). The postoperative SE was -0.07 ± 0.52D, -0.14 ± 0.38D, and -0.05 ± 0.46D after SMILE in the three groups, respectively (p = 0.376). No significant difference was found in mesopic/photopic CS, HOAs, and visual quality among different corneal thickness groups and SE groups. Postoperative SE and efficacy indices were the lowest in thin cornea eyes with ultra-high myopia (over -9.00 D). CONCLUSIONS SMILE provides comparable safety, efficacy, and visual quality results in different corneal thickness patients. Those with myopia higher than -9.00 D had less efficacy after surgery, especially in thin cornea patients.
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Affiliation(s)
- Xiuyu Mao
- Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, China
| | - Shunmei Ji
- Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, China
| | - Han Chen
- Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Fujian Provincial Hospital, Fujian, China
| | - Jinhui Dai
- Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, China
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Sun L, Lin HN, Jhanji V, Ng TK, Ji RF, Zhang R. Changes in effective optical zone after small-incision lenticule extraction in high myopia. Int Ophthalmol 2022; 42:3703-3711. [PMID: 35781597 DOI: 10.1007/s10792-022-02367-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/28/2022] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate the four measurement approaches on the determination of effective optical zone (EOZ) using Scheimpflug tomography after small-incision lenticule extraction surgery in eyes with high myopia. SETTING Corneal refractive surgery conducted in an eye hospital in southern China. DESIGN This is a retrospective cohort study. METHODS In total, 74 subjects were recruited. EOZ was measured at 3 months postoperatively using vertex-based (EOZV), pupil-based (EOZP), 4 mm-ring-based total corneal refraction method (EOZ4) and tangential curvature difference map method (EOZD), and their consistencies were compared. EOZs and planned optical zone (POZ) were compared and analyzed with eccentricity, ablation degree (AD) and total corneal aberrations. RESULTS At 3 months after surgery, the mean root mean square of ΔHOA, ΔComa, ΔTrefoil and ΔSA were 0.53 ± 0.27 μm, 0.36 ± 0.20 μm, 0.01 ± 0.84 μm and 0.16 ± 0.14 μm, respectively. EOZV, EOZP, EOZ4 and EOZD were 5.87 ± 0.44 mm, 5.85 ± 0.45 mm, 4.78 ± 0.40 mm and 5.29 ± 0.27 mm, respectively, which were significantly smaller than POZ 6.48 ± 0.16 mm. Bland-Altman plots showed a good consistency among the four EOZs. The difference between the EOZV and EOZP was 0.02 mm within the range of clinically acceptable difference. In addition, the eccentricity was positively correlated with ΔHOA, ΔComa and ΔSA. CONCLUSIONS All 4 measurement approaches demonstrated the reduction of EOZs compared to POZ. The EOZV was the closest to POZ, followed by EOZP. The ΔEOZs showed no significant difference with eccentricity, AD and corneal aberrations.
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Affiliation(s)
- Lixia Sun
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
| | - Hui-Ni Lin
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
| | - Vishal Jhanji
- Shantou University Medical College, Shantou, Guangdong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong
- Department of Ophthalmology, UPMC Eye Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
- Shantou University Medical College, Shantou, Guangdong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Rui-Feng Ji
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
| | - Riping Zhang
- Joint Shantou International Eye Center of Shantou University, The Chinese University of Hong Kong, North Dongxia Road, Shantou, 515041, Guangdong, China
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Liu S, Zhang X, Niu L, Yu Z, Zhou X, Zhao J. Comparison of the Functional Optical Zone in Eyes With High Myopia With High Astigmatism After SMILE and FS-LASIK. J Refract Surg 2022; 38:595-601. [PMID: 36098388 DOI: 10.3928/1081597x-20220725-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the functional optical zone (FOZ) in eyes with high myopia with high astigmatism after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS In total, 45 eyes of 45 patients with high myopia with astigmatism greater than 2.00 diopters (D) who underwent SMILE or FS-LASIK were enrolled. The FOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then compared between the two groups 6 months postoperatively. RESULTS No postoperative complications were observed during follow-up. The mean FOZ diameter was 5.03 ± 0.31 mm for the FS-LASIK group and 5.24 ± 0.27 mm for the SMILE group (P = .007), corresponding to reductions of 1.18 ± 0.23 and 1.01 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) (P = .013). A significant difference was noted in the FOZ on the short axis between the two groups (P = .002), whereas no significant difference was observed on the long axis (P = .088). The FOZ area in the FS-LASIK and SMILE groups was 65.39 ± 6.14% and 70.09 ± 5.46% of the POZ area, respectively (P = .010). There was no significant difference in decentration between the two groups (0.29 ± 0.13 mm for the FS-LASIK group vs 0.30 ± 0.13 mm for the SMILE group, P = .798). A significant increase in spherical aberration was observed in the FS-LASIK group (P < .001). However, the induction of vertical coma was higher in the SMILE group than in the FS-LASIK group (P = .002). CONCLUSIONS Eyes with high myopia with high astigmatism following SMILE achieved a larger FOZ and less spherical aberration but a larger vertical coma introduction than following FS-LASIK. [J Refract Surg. 2022;38(9):595-601.].
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Huang Y, Ding X, Han T, Fu D, Yu Z, Zhou X. Effective Optical Zone Following Small Incision Lenticule Extraction for Myopia Calculated With Two Novel Methods. J Refract Surg 2022; 38:414-421. [PMID: 35858198 DOI: 10.3928/1081597x-20220608-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the effective optical zone (EOZ) following small incision lenticule extraction in myopic eyes using two novel methods and investigate factors influencing postoperative EOZ. METHODS In this prospective study, 45 patients (45 eyes) with a mean spherical equivalent of -5.82 ± 1.58 diopters underwent SMILE and were observed during a 6-month follow-up. Postoperative EOZ was calculated using custom software that automatically distinguishes EOZ on the tangential curvature difference map (EOZc) and total corneal refractive power map (EOZp) of the Pentacam HR (Oculus Optikgeräte GmbH). The agreement between the two methods, the difference between postoperative EOZ and programmed optical zone (POZ), and its relationship with parameters including corrected spheres, cylinders, ablation ratio (ablation depth/central cornea thickness), and Q-value change were investigated. RESULTS The EOZc area was 20.76 ± 2.43 mm2 (diameter: 5.04 ± 0.60 mm) and the EOZp area was 20.22 ± 4.70 mm2 (diameter: 5.13 ± 0.30 mm). Both were significantly smaller than POZ (P < .001). Bland-Altman plots showed 4.44% (2/45) points located outside the 95% limits of agreement. EOZc and EOZp reductions were negatively related to corrected cylinders (r = -0.631, P < .001 and r = -0.594, P < .001, respectively). EOZp reduction was positively correlated with corrected spheres (r = 0.336, P = .024). Subgroup analysis revealed significant differences in EOZc and EOZp reduction between low and high astigmatism groups despite myopia degree. CONCLUSIONS EOZ after incision lenticule extraction, measured using two novel methods, was smaller than POZ. The reduction of EOZ was negatively correlated with the corrected cylinders. [J Refract Surg. 2022;38(7):414-421.].
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Liu S, Gu X, Zhang X, Zhao J, Zhou X. Achieved and Functional Optical Zone in Myopic Eyes With High Astigmatism After Small Incision Lenticule Extraction. J Refract Surg 2022; 38:243-249. [PMID: 35412923 DOI: 10.3928/1081597x-20220201-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the achieved optical zone and functional optical zone in myopic eyes with high astigmatism after small incision lenticule extraction (SMILE). METHODS Seventy-five eyes of 75 consecutive patients with myopia before SMILE were included and divided into two groups (no astigmatism group: without astigmatism vs high astigmatism group: with astigmatism > 2.00 diopters). The achieved optical zone, functional optical zone, and corneal aberrations were compared using Scheimpflug imaging at 6 months postoperatively. Correlations between corneal aberrations and functional optical zone were analyzed. RESULTS The mean achieved optical zone diameter was smaller in the no astigmatism group than in the high astigmatism group. There were no significant differences in achieved optical zone among the different meridians in each group. The mean functional optical zone diameter was significantly smaller in the no astigmatism group than in the high astigmatism group. Compared with the programmed optical zone, significant reduction of the functional optical zone was found in the two groups. The reduction of the functional optical zone was significantly smaller in the high astigmatism group than in the no astigmatism group, except for the 60°, 90°, and 120° meridians. There were significant correlations between the functional optical zone area and the induced corneal aberrations in the high astigmatism group, except for horizontal coma, whereas significant correlations of functional optical zone with total higher order aberrations and spherical aberration were detected in the no astigmatism group. CONCLUSIONS Myopic eyes with high astigmatism following SMILE had a circular achieved optical zone, but the functional optical zone was oval and larger than in eyes without astigmatism. Moreover, a lower spherical aberration was observed in the patients with high astigmatism. [J Refract Surg. 2022;38(4):243-249.].
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de Rojas Silva MV, Tobío Ruibal A, Suanzes Hernández J. Corneal power measurements by ray tracing in eyes after small incision lenticule extraction for myopia with a combined Scheimpflug Camera-Placido disk topographer. Int Ophthalmol 2021; 42:921-931. [PMID: 34799784 DOI: 10.1007/s10792-021-02073-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE To evaluate the accuracy of the measurements of corneal power obtained by ray tracing with a combined Scheimpflug camera-Placido disk corneal topographer (Sirius) in eyes after small incision lenticule extraction for myopia (SMILE). METHODS Retrospective cases study includes 50 eyes of 50 patients who underwent myopic SMILE. Mean value of simulated keratometry (Kpost), mean pupil power (MPP) (ray tracing, diameter of the entrance pupil range 3-6 mm), anterior and posterior corneal radius, and corneal thickness were obtained with Sirius topographer preoperatively and three months postoperatively, as well as cycloplegic refraction. True net power, equivalent keratometry readings, and Haigis equivalent power formula were calculated, and these measurements, MPP and Kpost, were compared with the corneal power calculated with the clinical history method (CHM). RESULTS Corneal power measurements obtained with all methods were significantly different from CHM (P < 0.001), except the value of MPP obtained at 5.5 mm (P = 0.927). A good direct correlation was found between CHM and all measurements. The distribution of differences as compared with the CHM showed that the lowest difference corresponded to the value of MMP at 5.5 mm (- 0.002 ± 0.6). The Bland-Altman plots for the MPP at 5.5 mm showed 95% limits of agreement between - 1.1787 D and 1.1741 D. CONCLUSIONS MPP obtained by ray tracing within a diameter of entrance pupil of 5.5 mm could predict corrected corneal power derived from the CHM in eyes following SMILE surgery.
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Affiliation(s)
- Mª Victoria de Rojas Silva
- Victoria de Rojas Instituto Oftalmológico, Policlínica Assistens, A Coruña, Spain. .,Department of Ophthalmology, Complexo Hospitalario Universitario, A Coruña, Spain.
| | - Adrián Tobío Ruibal
- Victoria de Rojas Instituto Oftalmológico, Policlínica Assistens, A Coruña, Spain
| | - Jorge Suanzes Hernández
- Research Support Unit, Complexo Hospitalario Universitario, A Coruña, Spain.,Institute of Biomedical Research (INIBIC), A Coruña, Spain
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[Regression and ablation profiles in corneal refractive surgery]. J Fr Ophtalmol 2021; 44:1059-1075. [PMID: 34148702 DOI: 10.1016/j.jfo.2020.08.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/16/2020] [Accepted: 08/24/2020] [Indexed: 11/21/2022]
Abstract
Regression after corneal refractive surgery is a complex phenomenon which seems inevitable. The choice of surgical technique has very little influence on regression for low myopia or myopic astigmatism. However, LASIK and SMILE are the two techniques of choice in the correction of high myopia. LASIK is also better for the correction of hyperopia, hyperopic astigmatism and mixed astigmatism. Intraoperatively, the choice of a wide optical zone and adherence to a thick residual stromal bed provide stability. Regression may also be reduced by modulating anti-inflammatory therapy, treating dry eye, and using mitomycin C in PKR. In all cases, obtaining keratometry during patient follow-up helps to identify the cause of the regression. The objective of this review is to synthesize recent data from the literature on regression in refractive surgery as a function of the ablation profiles used.
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Arba Mosquera S, Verma S. A review of clinical outcomes following SMILE for the treatment of astigmatism. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2020.1810017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Samuel Arba Mosquera
- Biomedical Engineering Office, Research and Development, SCHWIND Eye-tech-solutions GmbH, Kleinostheim, Germany
| | - Shwetabh Verma
- Biomedical Engineering Office, Research and Development, SCHWIND Eye-tech-solutions GmbH, Kleinostheim, Germany
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The best optical zone for small-incision lenticule extraction in high myopic patients. J Cataract Refract Surg 2020; 46:1302-1307. [PMID: 32569029 DOI: 10.1097/j.jcrs.0000000000000282] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Small-incision lenticule extraction (SMILE) is an effective and safe procedure for the correction of myopia due to minimally invasive and noncorneal flap surgery. However, the SMILE procedure has certain requirements for corneal cap thickness, attempted refractive correction, residual stromal bed thickness, and optical zone diameter, which sometimes make surgeons hesitant to choose SMILE or other refractive surgeries. The requirements limit its use in patients with high myopia. The purpose of this review was to find the optimal parameters of SMILE through discussing the best optical zone for high myopic patients, the visual quality of different optical zones, the choice of corneal cap thickness, and their effects on corneal biomechanical parameters, so surgeons can provide reference recommendations for patients with high myopia in choosing a reasonable and safe procedure.
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Qian Y, Chen X, Naidu RK, Zhou X. Comparison of efficacy and visual outcomes after SMILE and FS-LASIK for the correction of high myopia with the sum of myopia and astigmatism from -10.00 to -14.00 dioptres. Acta Ophthalmol 2020; 98:e161-e172. [PMID: 31912660 DOI: 10.1111/aos.14078] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 02/02/2019] [Indexed: 11/27/2022]
Abstract
PURPOSE To compare the efficacy and visual outcomes after femtosecond laser small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) in correcting high myopia. METHODS This prospective, randomized study included patients who underwent SMILE or FS-LASIK for the correction of high myopia [the sum of spherical and cylindrical error from -10.00 to -14.00 dioptres (D)]. Preoperative, 1-month (P1m), 3-months (P3m) and 6-months (P6m) postoperative outcomes were analysed and compared between the two procedures. RESULTS Ninety-six right eyes of 96 patients (SMILE: n = 51, FS-LASIK: n = 45) were included. Both the (Attempted - achieved) sphere and the (attempted - achieved) spherical equivalent (SEQ) were greater in the FS-LASIK group at all three postoperative time-points (p < 0.001). The postoperative vector means of astigmatism were smaller in the SMILE group than in the FS-LASIK group. The differences between the optical zone of tissue removal (ROZ) during surgery and the postoperative functional optical zone (FOZ; ROZ-FOZ) were smaller in the SMILE group than in the FS-LASIK group. No significant difference was found between the two procedures in the delta-root mean square (RMS) of aberrations, except for delta-spherical aberration (SA) at P3m. CONCLUSIONS Both SMILE and FS-LASIK are effective in correcting high myopia. SMILE resulted in less under-correction, less regression, a smaller decrease in the FOZ and a smaller increase in SA when compared to FS-LASIK, resulting in better visual outcomes with SMILE.
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Affiliation(s)
- Yishan Qian
- Department of Ophthalmology Eye and ENT Hospital of Fudan University Shanghai China
- Department of Ophthalmology NHC Key Laboratory of Myopia (Fudan University) Shanghai China
| | - Xun Chen
- Department of Ophthalmology Eye and ENT Hospital of Fudan University Shanghai China
- Department of Ophthalmology NHC Key Laboratory of Myopia (Fudan University) Shanghai China
| | | | - Xingtao Zhou
- Department of Ophthalmology Eye and ENT Hospital of Fudan University Shanghai China
- Department of Ophthalmology NHC Key Laboratory of Myopia (Fudan University) Shanghai China
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Hou J, Wang Y, Lei Y, Zheng X. Comparison of effective optical zone after small-incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis for myopia. J Cataract Refract Surg 2019; 44:1179-1185. [PMID: 30243392 DOI: 10.1016/j.jcrs.2018.06.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/15/2018] [Accepted: 06/19/2018] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare the effective optical zone (EOZ) after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). SETTING Jinan Mingshui Eye Hospital, Jinan, China. DESIGN Retrospective case series. METHODS Myopic patients who had small-incision lenticule extraction or FS-LASIK were enrolled in this retrospective study. Effective OZs were measured at 1 week, 1 month, and 3 months postoperatively, using the tangential curvature difference map of the Scheimpflug tomography system. Correlations between the changes in the EOZ and relevant parameters were analyzed 3 months postoperatively. RESULTS The study comprised 76 patients (76 eyes). The mean EOZs at 1 week, 1 month, and 3 months postoperatively were 5.39 ± 0.27 mm, 5.33 ± 0.30 mm, and 5.34 ± 0.23 mm in the small-incision lenticule extraction group and 5.06 ± 0.36 mm, 4.98 ± 0.39 mm, and 5.01 ± 0.31 mm in the FS-LASIK group, when the programmed OZ was 6.5 mm. The magnitude of decreases in EOZ was significantly smaller in the small-incision lenticule extraction group than in the FS-LASIK group at all timepoints after surgery (P < .01). There were significant correlations between changes in EOZ and corneal asphericity (P < .01). Epithelial thickening was positively correlated with EOZ reduction in the small-incision lenticule extraction group (r = 0.479, P < .01); however, no correlation was found between epithelial thickening and EOZ reduction in the FS-LASIK group (r = .324, P > .05). CONCLUSIONS Both small-incision lenticule extraction and FS-LASIK resulted in EOZ reduction during correction of myopia. However, small-incision lenticule extraction resulted in less reduction than FS-LASIK and was associated with corneal asphericity changes and epithelial thickening.
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Affiliation(s)
- Jie Hou
- From the Jinan Mingshui Eye Hospital (Hou, Lei, Zheng), Jinan, and the Tianjin Eye Hospital (Wang), Tianjin Key Laboratory of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Yan Wang
- From the Jinan Mingshui Eye Hospital (Hou, Lei, Zheng), Jinan, and the Tianjin Eye Hospital (Wang), Tianjin Key Laboratory of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
| | - Yulin Lei
- From the Jinan Mingshui Eye Hospital (Hou, Lei, Zheng), Jinan, and the Tianjin Eye Hospital (Wang), Tianjin Key Laboratory of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Xiuyun Zheng
- From the Jinan Mingshui Eye Hospital (Hou, Lei, Zheng), Jinan, and the Tianjin Eye Hospital (Wang), Tianjin Key Laboratory of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
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Liu Q, Yang X, Lin L, Liu M, Lin H, Liu F, Xie Y, Lam DS. Review on Centration, Astigmatic Axis Alignment, Pupil Size and Optical Zone in SMILE. Asia Pac J Ophthalmol (Phila) 2019; 8:385-390. [PMID: 31567265 PMCID: PMC6784779 DOI: 10.1097/01.apo.0000580144.22353.46] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/06/2019] [Indexed: 11/25/2022] Open
Abstract
The advent of "flapless" small-incision lenticule extraction (SMILE), employing all-in-one technology, has resulted in a revolutionary breakthrough in refractive surgeries. SMILE has been gaining popularity due to fewer potential complications, such as postoperative dry eyes and greater biomechanical stability, etc. However, attention must be given to 1) the centration on the corneal vertex, 2) the proper alignment of the astigmatic axis, and 3) the relationship between pupil size and treatment diameter, to achieve good SMILE results. There is no pupil-tracking system to ascertain the accuracy of centration during the SMILE surgery. To improve the centration accuracy, our center uses two corneal topographers (Pentacam and Sirius) to measure and determine corneal vertex. Proper predicted optical zone diameter is not clearly defined yet in SMILE. Some scholars insist that mesopic pupil size should be taken into consideration when setting the predicted optical zone. Meanwhile, the issue of "functional optical zone" still has many unresolved issues and warrants further studies.
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Affiliation(s)
- Quan Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiaonan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Limian Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Manli Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Haiqin Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Fang Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yi Xie
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Dennis S.C. Lam
- International Eye Research Institute of the Chinese University of Hong Kong (Shenzhen), Shenzhen, China
- C-MER (Shenzhen) Dennis Lam Eye Hospital, Futian, Shenzhen, China
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Damgaard IB, Ang M, Mahmoud AM, Farook M, Roberts CJ, Mehta JS. Functional Optical Zone and Centration Following SMILE and LASIK: A Prospective, Randomized, Contralateral Eye Study. J Refract Surg 2019; 35:230-237. [PMID: 30984980 DOI: 10.3928/1081597x-20190313-01] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 03/13/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare centration and functional optical zone (FOZ) after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (LASIK). METHODS In this prospective, randomized, single-masked, paired-eyed, clinical trial, 70 patients received SMILE in one eye and LASIK in the other eye for myopia and myopic astigmatism. FOZ was calculated using custom software on 3-month postoperative refractive power maps (Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany). Programmed treatment area was defined as the total area of the programmed OZ plus the transition zone. Centration was evaluated by the linear distance between FOZ centroid and the pupil center and the corneal apex. RESULTS The average preoperative spherical equivalent (-5.38 ± 1.65 vs -5.45 ± 1.61 diopters [D]), postoperative spherical equivalent (0.05 ± 0.39 vs 0.06 ± 0.39 D), uncorrected distance visual acuity (0.01 ± 0.13 vs 0.00 ± 0.08 logMAR), and corrected distance visual acuity (-0.07 ± 0.10 vs -0.07 ± 0.10 logMAR) were comparable in SMILE- and LASIK-treated eyes of the 60 patients with complete datasets (P > .419). Postoperative increase in spherical aberration was lower in SMILE than in LASIK (0.08 ± 0.16 vs 0.17 ± 0.18 µm, P = .002). The FOZ area was significantly larger in SMILE than in LASIK (30.25 ± 3.60 vs 29.21 ± 3.72 mm2), despite the smaller programmed OZ diameter (6.48 ± 0.08 vs 6.52 ± 0.11 mm) and smaller programmed treatment area (33.87 ± 0.81 vs 46.30 ± 2.61 mm2, P < .037). Pupil centration (0.43 ± 0.21 vs 0.41 ± 0.22 mm) and apex centration (0.48 ± 0.24 vs 0.48 ± 0.22 mm) were comparable between SMILE and LASIK (P > .694). CONCLUSIONS SMILE created a larger FOZ than LASIK, despite the smaller programmed OZ. This may be due to a difference in the biomechanical response between the two procedures. Visual outcome and centration were comparable between SMILE and LASIK. [J Refract Surg. 2019;35(4):230-237.].
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Pan C, Tan W, Hua Y, Lei X. Comprehensive evaluation of total corneal refractive power by ray tracing in predicting corneal power in eyes after small incision lenticule extraction. PLoS One 2019; 14:e0217478. [PMID: 31170272 PMCID: PMC6553727 DOI: 10.1371/journal.pone.0217478] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/13/2019] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To assess the prediction accuracy of four variations of total corneal refractive power (TCRP) by the ray tracing method in determining corneal power in eyes after myopic small incision lenticule extraction (SMILE). METHODS Forty eyes of forty patients who had undergone myopic SMILE were enrolled in this prospective study. Manifest refraction and Pentacam HR were performed preoperatively and three months or more postoperatively. Mean keratometry (Km), true net power (TNP), equivalent keratometry readings (EKR) and 4 subtypes of TCRP (pupil centered or apex centered within a ring or a zone)-TCRPpupil,ring, TCRPpupil,zone, TCRPapex,ring and TCRPapex,zone-were recorded and compared to the theoretical postoperative keratometry value using the clinical history method (CHM). RESULTS The only keratometric values that showed no statistically significant differences from the CHM were 4.0 mm and 4.5 mm EKR, 6.0 mm TCRPpupil,zone and TCRPapex,zone. Pearson's correlation test revealed that 4.0 mm TCRPpupil,zone exhibited the highest correlation coefficient (r = 0.974) followed by TCRPapex,zone 4.0 mm (0.972) and EKR 4.5 mm (0.970). The 95% limits of agreement (LOA) of the 4.0 mm EKR and CHM, the 4.5 mm EKR and CHM, the 6.0 mm TCRPpupil,zone and CHM, the 6.0 mm TCRPapex,zone and CHM were (-1.27 to 1.22 D), (-1.04 to 0.98 D), (-1.39 to 1.08 D) and (-1.38 to 0.96 D), respectively, while the modified 4.0 mm TCRPpupil,zone (TCRPpuil,zone + 0.70 D) and TCRPapex,zone (TCRPapex,zone+0.70 D) yielded the narrowest 95% LOA of (-0.96 to 0.95 D) and (-0.96D, 1.05 D). CONCLUSIONS Total corneal refractive power using the ray tracing method could predict corrected corneal power derived from the CHM in eyes following SMILE surgery after simple modification.
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Affiliation(s)
- Chao Pan
- Hankou Aier Eye Hospital, Jianghan District, Wuhan, Hubei Province, China
| | - Weina Tan
- Hankou Aier Eye Hospital, Jianghan District, Wuhan, Hubei Province, China
| | - Yanjun Hua
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Xuhui District, Shanghai, China
| | - Xiaohua Lei
- Hankou Aier Eye Hospital, Jianghan District, Wuhan, Hubei Province, China
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Pan C, Tan W, Hua Y, Lei X. Corneal power measurement with a new aberrometer/corneal topographer in eyes after small incision lenticule extraction for myopia. Int Ophthalmol 2019; 39:2815-2824. [PMID: 31134424 DOI: 10.1007/s10792-019-01128-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/22/2019] [Indexed: 11/27/2022]
Abstract
PURPOSE To assess corneal power measurements obtained by the OPD SCAN III Topographer in eyes with prior myopic small incision lenticule extraction (SMILE) surgery. METHODS Sixty untreated myopic eyes of sixty subjects and forty previous myopic SMILE surgery eyes of forty subjects were consecutively enrolled in the present study. Manifest refraction, OPD SCAN III and Pentacam HR were performed. Keratometric measurements assessed by OPD SCAN III-simulated keratometry, average pupil power and effective central corneal power (ECCP) were compared with mean keratometry (Km) obtained by Pentacam HR in the untreated group and the clinical history method (CHM) in the treated group. RESULTS In the untreated group, no statistically significant differences were revealed between all corneal power measurements obtained with OPD SCAN III and Km. In the treated group, all the corneal power measurements were statistically different from the CHM except for the Haigis method and the Shammas method, while ECCP had a statistically but not clinically significant overestimation of 0.42 D with 95% limit of agreement (LOA) of - 0.81 D to 1.64 D. The three modified ECCP had better prediction performance with narrower 95% of LOA lying in (- 1.20, 1.20 D) (- 1.22, 1.23 D) and (- 0.90, 1.00 D), respectively. CONCLUSIONS The ECCP provided with OPD SCAN III could be used as an alternative option for the CHM after specific modifications in eyes with previous myopic SMILE surgery when the preoperative data are unavailable considering the narrowest agreement between the modified ECCP and the CHM. Otherwise, caution must be raised considering the wide LOA.
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Affiliation(s)
- Chao Pan
- Hankou Aier Eye Hospital, 34 Machang Road, Jianghan District, Wuhan, Hubei Province, China
| | - Weina Tan
- Hankou Aier Eye Hospital, 34 Machang Road, Jianghan District, Wuhan, Hubei Province, China
| | - Yanjun Hua
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Xuhui District, Shanghai, China
| | - Xiaohua Lei
- Hankou Aier Eye Hospital, 34 Machang Road, Jianghan District, Wuhan, Hubei Province, China.
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Abstract
To evaluate surgically induced refractive change (SIRC) by manifest refraction and corneal power changes using an automated keratometer and Scheimpflug rotating camera, and to find the best keratometric measurements reflecting SIRC after hyperopic laser-assisted in situ keratomileusis (LASIK).This retrospective study included 18 eyes of 18 patients undergoing hyperopic LASIK using the Schwind Amaris 750S excimer laser. All measurements were performed preoperatively and 12 months postoperatively. Cycloplegic manifest refractions were performed and keratometric measurements were obtained via an RK-5 automated keratometer and a Pentacam rotating Scheimpflug camera. Sim K, true net power (TNP), and total corneal refractive power (TCRP) at 2.0 to 5.0 mm were analyzed using a Scheimpflug camera.The mean manifest refractive changes in the spherical equivalent (SE) at the corneal plane were 2.32 ± 1.65 D at 12 months postoperatively. The refractive power changes by the automated keratometer and Sim K were significantly less than SIRC (P = .043 and P = .048, respectively). Both TNP and the TCRP in the 5.0 mm zone produced lesser mean differences with SIRC (0.05 D and 0.06 D) and showed closer agreements with SIRC on Bland-Altman plots and higher correlation coefficients with SIRC.Corneal power measured on the anterior corneal surface underestimated SIRC. TCRP at the 5.0 mm zone provided by a Pentacam Scheimpflug camera reflected the SIRC accurately and precisely, and would be applicable for prediction of intraocular power before cataract surgery and follow-up measurement of corneal refractive power.
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Affiliation(s)
- Woong-Joo Whang
- Department of Ophthalmology and Visual Science, Yeouido St. Mary's Hospital
| | - Young-Sik Yoo
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Choun-Ki Joo
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
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Functional Optical Zone After Small-Incision Lenticule Extraction as Stratified by Attempted Correction and Optical Zone. Cornea 2018; 37:1110-1117. [PMID: 29927753 DOI: 10.1097/ico.0000000000001669] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare the functional optical zone (OZ) with different levels of myopia and different OZ groups after small-incision lenticule extraction. METHODS This retrospective study included 249 patients (120 men) after small-incision lenticule extraction correction. We grouped participants according to attempted correction [low: spherical equivalent (SE) > -3.0 D; moderate: -6.0 D ≥ SE ≥ -3.0 D; high: SE ≥ -6.0 D] and planned functional optical zone (PFOZ) (OZ-1: PFOZ ≤ 6.3 mm; OZ-2: 6.3 mm < PFOZ ≤ 6.5; OZ-3: PFOZ > 6.5 mm), and we compared the achieved functional optical zone (AFOZ) and total corneal aberration, using Scheimpflug imaging, 1 month postoperatively. Correlations between corneal aberration and AFOZ were analyzed. RESULTS The AFOZ was smaller than the PFOZ in all 3 refraction groups (reduction: low, 0.78 ± 0.72 mm; moderate, 1.22 ± 0.60 mm; and high: 1.49 ± 0.58 mm, P < 0.001). There was no difference in the AFOZ among the 3 OZ groups. Total corneal aberration increased more in the high myopia group (total higher-order aberration, coma, and spherical aberration, P < 0.001), which also correlated with the AFOZ. CONCLUSIONS The discrepancy between the AFOZ and PFOZ increased with greater attempted correction. Attempted correction and AFOZ influence corneal aberration.
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Han T, Xu Y, Han X, Zeng L, Shang J, Chen X, Zhou X. Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism. Br J Ophthalmol 2018; 103:565-568. [PMID: 30061116 PMCID: PMC6691872 DOI: 10.1136/bjophthalmol-2018-312140] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/18/2018] [Accepted: 06/22/2018] [Indexed: 11/22/2022]
Abstract
Aims To compare long-term clinical outcomes following small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism correction. Methods In this retrospective study, we enrolled a total of 101 patients (101 eyes) who underwent SMILE or FS-LASIK 3 years prior. Measured parameters included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction and corneal wavefront aberrations. Results No significant differences in patient characteristics were found between the two groups. At the 3-year follow-up, UDVA was better than or equal to 20/20 in 90% and 85% (p=0.540) of the eyes; the efficacy indexes were 1.05±0.19 and 1.01±0.21 in the SMILE and FS-LASIK groups, respectively (p=0.352). Safety indexes were 1.19±0.17 and 1.15±0.20 in the SMILE and FS-LASIK groups, respectively (p=0.307). Eighty per cent and 65% of eyes were within ±0.50 D of the attempted spherical equivalent correction after SMILE and FS-LASIK, respectively (p=0.164). Vector analysis revealed no significant differences in astigmatic correction between the two groups (p>0.05). Surgically induced spherical aberration was higher in the FS-LASIK group than in the SMILE group (p<0.001). Conclusion Long-term follow-up analysis suggested that both SMILE and FS-LASIK were safe and equally effective for myopic and astigmatic correction.
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Affiliation(s)
- Tian Han
- The Key Lab of Myopia, Ministry of Health, Shanghai, China.,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
| | - Ye Xu
- The Key Lab of Myopia, Ministry of Health, Shanghai, China.,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
| | - Xiao Han
- The Key Lab of Myopia, Ministry of Health, Shanghai, China.,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
| | - Li Zeng
- The Key Lab of Myopia, Ministry of Health, Shanghai, China.,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
| | - Jianmin Shang
- The Key Lab of Myopia, Ministry of Health, Shanghai, China.,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
| | - Xun Chen
- The Key Lab of Myopia, Ministry of Health, Shanghai, China.,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
| | - Xingtao Zhou
- The Key Lab of Myopia, Ministry of Health, Shanghai, China .,Department of Ophthalmology, The Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry , Shanghai, China
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