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Liu X, Liu Q, Yu LH, Xiong R, Liu ST, You ZP. Three-year results of central corneal stromal thickness reduction in small-incision lenticule extraction for high myopia correction. Photodiagnosis Photodyn Ther 2024; 48:104278. [PMID: 39002832 DOI: 10.1016/j.pdpdt.2024.104278] [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: 05/16/2024] [Revised: 06/23/2024] [Accepted: 07/10/2024] [Indexed: 07/15/2024]
Abstract
BACKGROUND To investigate the long-term corneal stromal remodeling and central stromal thickness (CST) reduction accuracy after small-incision lenticule extraction (SMILE) for high myopia correction. METHODS This prospective study included 30 patients (50 eyes) who had undergone SMILE. Measurements of CST reduction using optical coherence tomography were performed at 1 month, 6 months, 1 year, and 3 years after surgery. Correlations were performed between planned and achieved CST reductions. RESULTS The study enrolled 50 eyes of 30 patients. The mean spherical equivalent was -9.25±1.52 D(diopters). The postoperative CST increased in the first month after surgery and remained stable for a year. Thereafter, it remained stable during follow-up from 1 to 3 years postoperatively. The predicted CST reduction was 146.4 ± 10.3 μm. The achieved CST reductions at 1 month, 6 months, 1 year, and 3 years after surgery were 135.3 ± 12.1 μm, 130.8 ± 10.6 μm, 125.9 ± 9.4 μm, and 122.2 ± 10.6 μm, respectively. An overestimation of CST reduction was observed three years after surgery. Correlation analysis revealed a strong correlation between planned and achieved CST reductions; however, no correlation was found between CST reductions predicted error and the planned CST reductions. CONCLUSION During long-term follow-up, our findings revealed a significant stromal remodeling following SMILE in patients with high myopia. Therefore, clinicians should consider it when screening patients with high myopia for SMILE.
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Affiliation(s)
- Xian Liu
- The Affiliated Eye Hospital, Jiangxi Medical College, Nanchang University, No. 463 Bayi Avenue, Nanchang City, Nanchang, Jiangxi 330000, China
| | - Qiang Liu
- The Affiliated Eye Hospital, Jiangxi Medical College, Nanchang University, No. 463 Bayi Avenue, Nanchang City, Nanchang, Jiangxi 330000, China
| | - Lan-Hui Yu
- The Affiliated Eye Hospital, Jiangxi Medical College, Nanchang University, No. 463 Bayi Avenue, Nanchang City, Nanchang, Jiangxi 330000, China
| | - Rui Xiong
- The Affiliated Eye Hospital, Jiangxi Medical College, Nanchang University, No. 463 Bayi Avenue, Nanchang City, Nanchang, Jiangxi 330000, China
| | - Sheng-Tao Liu
- Department of Ophthalmology and Optometry, Eye and ENT Hospital, Key Lab of Myopia, Ministry of Health, Fudan University, No. 83 Fenyang Road, Shanghai 200031, China.
| | - Zhi-Peng You
- The Affiliated Eye Hospital, Jiangxi Medical College, Nanchang University, No. 463 Bayi Avenue, Nanchang City, Nanchang, Jiangxi 330000, China.
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Abtahi MA, Beheshtnejad AH, Latifi G, Akbari-Kamrani M, Ghafarian S, Masoomi A, Sonbolastan SA, Jahanbani-Ardakani H, Atighechian M, Banan L, Nouri H, Abtahi SH. Corneal Epithelial Thickness Mapping: A Major Review. J Ophthalmol 2024; 2024:6674747. [PMID: 38205099 PMCID: PMC10776199 DOI: 10.1155/2024/6674747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/27/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.
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Affiliation(s)
| | | | - Golshan Latifi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Sadegh Ghafarian
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Masoomi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | | | - Laleh Banan
- Sunshine Coast University Hospital, Brisbane, Queensland, Australia
| | - Hosein Nouri
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed-Hossein Abtahi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Wu Y, Shen T, Tan L, He T, Zheng Q, Hong C. Corneal remodeling after SMILE for moderate and high myopia: short-term assessment of spatial changes in corneal volume and thickness. BMC Ophthalmol 2023; 23:402. [PMID: 37803347 PMCID: PMC10559442 DOI: 10.1186/s12886-023-03148-0] [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: 06/08/2023] [Accepted: 09/20/2023] [Indexed: 10/08/2023] Open
Abstract
PURPOSE To evaluate the early corneal remodeling and its influencing factors after Small incision lenticule extraction (SMILE) for moderate and high myopia. METHODS This was a retrospective study. Pre- and post-operative (1 week and 1, 3, 6 months) corneal volume (CV), mean keratometry (Km), and corneal thickness (CT) were measured by Scheimpflug tomography. CT at the central, thinnest point, and on concentric circles of 2, 4, and 6 mm diameter was recorded to assess corneal thickness spatial profile (CTSP) and percentage of thickness increase (PTI) in the moderate and high myopia groups, and to explore possible influencing factors. RESULTS After SMILE, the peripheral CT decreased in the moderate myopia group and central corneal thickness (CCT) increased in the high myopia group at 1 month compared to 1 week (all P < 0.05). The CV, Km and CT were significantly increased at 3 months compared to 1 month (all P < 0.05), but there was no significant change at 6 months compared to 3 months for both groups (all P > 0.05). Patients with high myopia showed greater corneal thickness changes (△CT) and higher PTI than moderate myopia (all P < 0.05). Regression analysis revealed that in addition to refraction, peripheral PTI was negatively correlated with CCT in the moderate myopia group (4 mm: β = -0.023, P = 0.001; 6 mm: β = -0.050, P < 0.001), as well as in the high myopia group (4 mm: β = -0.038, P < 0.001; 6 mm: β = -0.094, P < 0.001). Moreover, peripheral PTI in the moderate myopia group was negatively correlated with age (4 mm: β = -0.071, P = 0.003; 6 mm: β = -0.162, P < 0.001). CONCLUSIONS After SMILE, the CV, Km, and CTSP showed dynamic changes in the early stage, which stabilized after 3 months. Compared to the moderate myopia group, the high myopia group experienced slower corneal stabilization. The change in PTI at 6 months after SMILE may be related to higher preoperative refraction, thinner CCT and younger age.
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Affiliation(s)
- Yuanpeng Wu
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Ting Shen
- Eye Center, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
| | - Lingtong Tan
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ting He
- School of Public Health, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Qingqing Zheng
- Department of Ophthalmology, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Chaoyang Hong
- Department of Ophthalmology, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang, China.
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Tian G, Chen T, Liu X, Lin Y, Li N, Gao H, Liu M. Comparison of central corneal thickness treated with small incision lenticule extraction, femtosecond laser-assisted in situ keratomileusis, or laser-assisted subepithelial keratomileusis for myopia. Lasers Med Sci 2023; 38:198. [PMID: 37656340 DOI: 10.1007/s10103-023-03862-7] [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: 05/24/2023] [Accepted: 08/21/2023] [Indexed: 09/02/2023]
Abstract
To compare the central corneal thickness (CCT) treated with small incision lenticule extraction (SMILE), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), or laser-assisted subepithelial keratomileusis (LASEK) for myopia correction. This was a retrospective case series study. Patients who had completed 1-year follow-up after receiving SMILE, FS-LASIK, or LASEK at our hospital from January 2019 to July 2021 were included. Pentacam pachymetry was performed to measure the CCT. The predicted CCT reduction was obtained through laser platform. The measured CCT reduction was defined as the difference between the preoperative and postoperative CCT using Pentacam pachymetry. There were 100 eyes treated by SMILE, 100 eyes by FS-LASIK, and 100 eyes by LASEK. There was a significant difference in predicted CCT reduction among the three surgeries (P < 0.001), but no significant difference in measured CCT reduction postoperatively (PGroup = 0.373). At 1 year postoperatively, the CCT reduction was overestimated by 17.85 ± 5.36 µm in the SMILE group, underestimated by 4.31 ± 7.08 µm in the FS-LASIK group, and underestimated by 7.60 ± 8.28 µm in the LASEK group (PGroup < 0.001, PTime < 0.001). In the FS-LASIK group, the difference between predicted and measured CCT reduction was not related to the predicted CCT reduction (P = 0.095). The laser platform may overestimate the CCT reduction for SMILE and underestimate it for FS-LASIK and LASEK. FS-LASIK has a much higher level of accuracy in CCT reduction, which is not influenced by refractive correction.
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Affiliation(s)
- Ge Tian
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Tong Chen
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Xin Liu
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Yue Lin
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Na Li
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Hua Gao
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China
- School of Ophthalmology, Shandong First Medical University, Jinan, China
| | - Mingna Liu
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China.
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, China.
- School of Ophthalmology, Shandong First Medical University, Jinan, China.
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Zhu M, Xin Y, Vinciguerra R, Wang Z, Warsame AM, Wang C, Zhu D, Qu Z, Wang P, Zheng X, Wang J, Wang Q, Ye Y, Chen S, Bao F, Elsheikh A. Corneal Epithelial Remodeling in a 6-Month Follow-up Period in Myopic Corneal Refractive Surgeries. J Refract Surg 2023; 39:187-196. [PMID: 36892243 DOI: 10.3928/1081597x-20230113-02] [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: 03/10/2023]
Abstract
PURPOSE To investigate corneal epithelial thickness changes during a 6-month follow-up period after transepithelial photorefractive keratectomy (tPRK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE). METHODS This prospective study included 76 eyes of 76 participants who underwent myopic refractive surgery (23 FS-LASIK, 22 SMILE, and 31 tPRK). Epithelial thickness and anterior curvature were averaged over 4 regions (subdivided into 25 areas) and measured by spectral-domain optical coherence tomography and Scheimpflug tomography before the operation (pre) and at 1 or 3 days (pos1-3d), 1 week (pos1w), and 1 month (pos1m), 3 months (pos3m), and 6 months (pos6m) postoperatively. RESULTS The epithelial thickness of the three groups was similar in both the pre and pos6m (all P > .05), but the tPRK group fluctuated the most during the follow-up period. The largest increase was in the inferior-temporal paracentral area (7.25 ± 2.58 μm for FS-LASIK; 5.79 ± 2.41 μm for SMILE; 4.88 ± 5.84 μm for tPRK; all P < .001). Only the epithelial thickness of tPRK increased from pos3m to pos6m (P < .05), whereas all changes for FS-LASIK and SMILE were not significant (P > .05). A positive correlation of thickness changes with curvature gradient in the paracentral region of tPRK was found (r = 0.549, P = .018), but not in other regions in all groups. CONCLUSIONS Epithelial remodeling followed different trends after different surgeries from the early postoperative stage onward, but exhibited similar values at pos6m. Although remodeling after FS-LASIK and SMILE stabilized by pos3m, it remained unstable at pos6m after tPRK. These changes may affect corneal profile and lead to deviation from the intended surgical outcome. [J Refract Surg. 2023;39(3):187-196.].
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Liu M, Jin C, Lu L, Yuan Y, Chen C, Zhao T, Ke B. The Impact of Corneal Epithelial Thickening and Inhomogeneity on Corneal Aberrations After Small Incision Lenticule Extraction. J Refract Surg 2023; 39:23-32. [PMID: 36630428 DOI: 10.3928/1081597x-20221109-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE To investigate the corneal epithelial remodeling profile after small incision lenticule extraction (SMILE), the correlated explanatory variables, and its potential impact on corneal higher order aberrations (HOAs). METHODS This single-center study prospectively evaluated 75 right eyes of 75 patients scheduled for SMILE. An anterior segment optical coherence tomography device was used to automatically obtain central 6-mm corneal epithelial thickness (ET), total corneal HOAs, and individual Zernike components before and after surgery. The ET inhomogeneity over the central 3- and 6-mm cornea was quantified with coefficient of variance (CV). RESULTS Both ET and CV significantly increased 1 month postoperatively (all P < .05). The stepwise multiple regression analysis showed that ET and CV were significantly correlated with preoperative ET and CV, respectively (all P < .01). The corrected spherical equivalent also significantly influenced ET and CV (all P < .01). Over the central 6-mm zone, the alterations of total corneal HOAs and individual Zernike components such as vertical coma (Z7) and spherical aberration (Z12, Z24) were significantly correlated with ET and CV (all P < .05). CONCLUSIONS The SMILE-induced epithelial remodeling involved both ET and ET inhomogeneity. The modulation was associated with preoperative and treatment parameters, and exerted a significant impact on corneal HOA alterations especially over the central 6-mm cornea. Together with the amount of correction and corneal curvature gradient change, preoperative assessment of ET and ET inhomogeneity might help predict postoperative epithelial remodeling. [J Refract Surg. 2023;39(1):23-32.].
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Kim BK, Chung YT. Comparison of Changes in Corneal Thickness and Curvature After Myopia Correction Between SMILE and FS-LASIK. J Refract Surg 2023; 39:15-22. [PMID: 36630439 DOI: 10.3928/1081597x-20221130-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE To comparatively investigate the changes in corneal thickness and curvature between small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS Data were collected preoperatively and postoperatively at 1 week, 1 month, and 3 months, including central corneal thickness (CCT), midperipheral corneal thickness (MPCT), peripheral corneal thickness (PCT), central keratometry (CK), midperipheral keratometry (MPK), and peripheral keratometry (PK), using a dual rotating Scheimpflug analyzer. RESULTS At 1 week postoperatively, changes in CCT, MPCT, PCT, and PK were significantly greater in the SMILE group than in the FS-LASIK group (P = .003 for CCT and < .001 for MPCT, PCT, and PK), but no significant inter-group differences were found between changes in CK and MPK (P = .883 and .513, respectively). CCT, MPCT, and PK values showed a similar increase in both groups, but significantly more increase in PCT and significantly less increase in CK and MPK was observed in the SMILE group from 1 week to 3 months after surgery. At 3 months postoperatively, CCT and MPCT were significantly thinner in the SMILE group than in the FSLASIK group (P = .018 and .022, respectively), and there was no significant difference in PCT, CK, MPK, and PK between the two groups. CONCLUSIONS SMILE caused significantly more corneal thinning at the center, midperiphery, and periphery, and more corneal flattening at the periphery, compared to FS-LASIK. A different pattern of corneal remodeling was observed between the two surgeries during the 3-month follow-up period. [J Refract Surg. 2023;39(1):15-22.].
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Fu Y, Yin Y, Zhao Y, Li Y, Lu Y, Xiang A, Fu Q, Hu T, Du K, Hu S, Wu X, Wen D. Changes of the effective optical zone after small-incision lenticule extraction and a correlation analysis. Lasers Med Sci 2022; 38:14. [PMID: 36547739 DOI: 10.1007/s10103-022-03666-1] [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: 01/18/2022] [Accepted: 10/17/2022] [Indexed: 12/24/2022]
Abstract
The objective of the study is to observe the changes in the effective optical zone (EOZ) after small incision lenticule extraction (SMILE) and explore possible correlations with some influencing factors. In total, 133 eyes after SMILE were divided into the mild to moderate myopia group (- 1.75 D to - 5.75 D, 70 eyes) and the high myopia group (- 6.00 D to - 9.50 D, 63 eyes). The postoperative EOZ was calculated by utilizing the corneal tangential curvature map. Changes in EOZ (△-OZ) were monitored and compared between the two groups. Pearson correlation analysis was conducted to determine the correlation between △-OZ and corneal high-order wavefront aberrations. Multicollinearity analysis and ridge regression analysis were performed to assess the correlation between △-OZ and some corneal parameters. After SMILE, the horizontal EOZ (H-EOZ), vertical EOZ (V-EOZ), and average EOZ (A-EOZ) were significantly smaller than the programmed optical zone (POZ) in both groups (p < 0.05). The difference between V-EOZ and POZ (△V-OZ) and the difference between A-EOZ and POZ (△A-OZ) showed more significant changes in the high myopia group than in the mild to moderate myopia group, and △V-OZ was significantly larger than the difference between H-EOZ and POZ (△H-OZ) in the high myopia group. In both groups, the total high-order aberration (T-HOA) and spherical aberration (SA) both increased after SMILE, and they had a similar significant negative correlation with A-EOZ. Moreover, there was a significant negative correlation between △-OZ and Km (X1), Q-value (X2), spherical equivalent (SE, X3), ablating depth (AD, X4) and △e (X6), and a significant positive correlation between △-OZ and △Q (X5). △H-OZ was expressed as Y1, △V-OZ as Y2, and △A-OZ as Y3. The multiple linear regression equations were as follows: Y1 = 3.683 - 0.065X1, Y2 = 1.549 - 0.469X2 - 0.059X3, Y3 = 4.015 - 0.07X1 - 0.03X3, Y1 = 1.337 - 0.005X4 + 0.413X5, Y2 = 1.265 + 0.469X5, and Y3 = 0.852 - 0.002X4 - 0.398X6. The correlation degree with △A-OZ was ranked as Km > △Q > Q-value > AD > e-value > △e > SE > △Km, as represented by the ridge regression analysis. The EOZ was irregularly reduced after SMILE, which should be taken into consideration in the design of POZ, especially for high myopia. Consideration of the refractive diopter and corneal topography is advised for the design of POZ, the latter of which has greater reference significance.
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Affiliation(s)
- Yanyan Fu
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Yewei Yin
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Yang Zhao
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Yuanjun Li
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Ying Lu
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Aiqun Xiang
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Qiuman Fu
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Tu Hu
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Kaixuan Du
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Shengfa Hu
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Xiaoying Wu
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China
| | - Dan Wen
- Eye Center of Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- Hunan Key Laboratory of Ophthalmology, Changsha, 410008, Hunan, China.
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Leccisotti A, Fields SV, De Bartolo G. Change in Stromal Thickness and Anterior Curvature After Refractive Corneal Lenticule Extraction With the CLEAR Application. J Refract Surg 2022; 38:797-804. [PMID: 36476300 DOI: 10.3928/1081597x-20221107-01] [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: 12/12/2022]
Abstract
PURPOSE To measure the changes in stromal thickness and anterior corneal curvature after corneal lenticule extraction for the correction of myopia and myopic astigmatism with the Corneal Lenticule Extraction for Advanced Refractive correction (CLEAR) application (Ziemer Group). METHODS The correlations between achieved correction on maximum myopic meridian and stromal thinning and spherical equivalent of achieved correction and anterior corneal flattening were evaluated by optical coherence tomography 6 months after CLEAR in 78 eyes of 78 patients in a retrospective, consecutive, non-comparative case series study. RESULTS With an optical zone of 6.5 mm (52 eyes), the mean correction achieved was -5.80 ± 1.52 diopters (D) (range: -2.25 to -9.25 D), the mean stromal thinning was 104 ± 15 µm (range: 76 to 138 µm), and the regression line was: µm of thinning = 8.46 • D of correction + 55.25. With an optical zone of 6 mm (26 eyes), the mean correction achieved was -8.33 ± 1.61 D (range: -5.50 to -11.00 D), the mean stromal thinning was 114 ± 12 µm (range: 93 to 144 µm), and the regression line was: µm of thinning = 6.35 • D of correction + 60.92. With 6.5 mm, the mean corneal flattening was 4.27 ± 0.88 D, and the regression line was: D of flattening = 0.50 • D of correction + 1.60. With 6 mm, the mean corneal flattening was 6.40 ± 0.70 D, and the regression line was: D of flattening = 0.37 • D of correction + 2.36. CONCLUSIONS Stromal thinning and anterior corneal flattening were correlated with the amount of myopic correction in a linear fashion. The thinning was significantly less than predicted by the laser software. [J Refract Surg. 2022;38(12):797-804.].
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Liu P, Yu D, Zhang B, Zhou S, Zhu H, Qin W, Ye X, Li X, Zhang Y, Bai Y, Wang Y, Shao Z. Influence of optical zone on myopic correction in small incision lenticule extraction: a short-term study. BMC Ophthalmol 2022; 22:409. [PMID: 36271372 PMCID: PMC9585829 DOI: 10.1186/s12886-022-02631-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To evaluate the influence of preoperative optical zone on myopic correction in small incision lenticule extraction. METHODS In this retrospective clinical study, 581 eyes from 316 patients underwent SMILE were selected, including 117 eyes in the small optical zone group (range from 6.0 to 6.4 mm) and 464 eyes in the large optical zone group (range from 6.5 to 6.8 mm). The measurements included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical, and cylinder were measured preoperatively and 3 months postoperatively. Propensity score match (PSM) analysis was performed with age, gender, eye (right/left), keratometry and preoperative spherical equivalent between two different groups. The influence of optical zones on postoperative refractive outcomes were evaluated using univariate regression analysis. RESULTS In total, 78 pairs of eyes were selected by PSM (match ratio 1:1). There were no differences in the age, gender, eye (right/left), keratometry or preoperative spherical equivalent between the small and large optical zone groups. However, the difference of postoperative spherical equivalent was significantly between groups. Patients with larger optical zones had a trend towards less undercorrection (P = 0.018). Univariate linear regression model analysis found that each millimeter larger optical zone resulted in 8.13% or 0.39D less undercorrection (P < 0.001). The dependency between the optical zones and postoperative spherical equivalent was significant in the higher preoperative myopia group (r = 0.281, P < 0.001), but not significant in the lower myopia group (r = 0.028, P = 0.702). CONCLUSION The diameter of optical zones would affect postoperative refractive outcomes in small incision lenticule extraction. This study indicated that larger optical zones induced less undercorrection, especially in patients with high myopia.
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Affiliation(s)
- Pan Liu
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Dongyu Yu
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Boyu Zhang
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Shiqi Zhou
- Harbin Medical University, No.157 Baojian Road, Nangang District, 150081, Harbin, Heilongjiang Province, China
| | - Haoran Zhu
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Wanyun Qin
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Xinqi Ye
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Xianghui Li
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Yan Zhang
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Ying Bai
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Yuan Wang
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China
| | - Zhengbo Shao
- Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China. .,Future Medical Laboratory, the Second Affiliated Hospital of Harbin Medical University, No.246 Xuefu Road, Nangang District, 150086, Harbin, Heilongjiang Province, China.
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Zhang D, Tian L, Zhang H, Zheng Y, Fu C, Zhai C, Jie Y, Li L. Differences of Corneal Biomechanics Among Thin Normal Cornea, Forme-Fruste Keratoconus, and Cornea After SMILE. Front Bioeng Biotechnol 2022; 10:861924. [PMID: 35646859 PMCID: PMC9136087 DOI: 10.3389/fbioe.2022.861924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
Background: To compare the corneal biomechanics of thin normal cornea (TNC) with thinnest corneal thickness (TCT) (≤500 µm), forme-fruste keratoconus (FFKC) and cornea after small incision lenticule extraction (Post-SMILE) had their central corneal thickness (CCT) matched by Corneal Visualization Scheimpflug Technology (Corvis ST).Methods: CCT were matched in 23 eyes with FFKC, 23 eyes by SMILE in 3 months post-operatively, and 23 TNC eyes. The differences in corneal biomechanics by Corvis ST among the three groups were compared.Results: There was no significant difference in CCT among the three groups, and the biomechanically corrected intraocular pressure (bIOP) did not differ significantly among the three groups (all p > 0.05). There were significant differences in most DCR parameters between pre- and post-operatively (all p < 0.05). Compared with TNC, the values of corneal deflection amplitude during the first applanation (A1DA), length at the first applanation (A1L), corneal deflection amplitude during the second applanation (A2DA), and maximum deformation amplitude (DA) decreased in 3 months after SMILE (all p < 0.05), these values increased in the FFKC (all p < 0.05).Conclusion: The majority of the DCR parameters were different among the three groups. The parameters A1DA, A1L, A2DA, and DA may be different between TNC and Post-SMILE, TNC and FFKC, and Post-SMILE and FFKC.
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Affiliation(s)
- Di Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China
- Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Lei Tian
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beijing Tongren Hospital, Beihang University and Capital Medical University, Beijing, China
| | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China
- Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Yan Zheng
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Caiyun Fu
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Changbin Zhai
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- *Correspondence: Lin Li, ; Changbin Zhai, ; Ying Jie,
| | - Ying Jie
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- *Correspondence: Lin Li, ; Changbin Zhai, ; Ying Jie,
| | - Lin Li
- School of Biomedical Engineering, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China
- Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
- *Correspondence: Lin Li, ; Changbin Zhai, ; Ying Jie,
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Luo Y, He S, Chen P, Yao H, He A, Li Y, Qiu J, Lan M, Zhuang J, Yu K. Predictability of Central Corneal Stromal Reduction After SMILE and FS-LASIK for High Myopia Correction: A Prospective Randomized Contralateral Eye Study. J Refract Surg 2022; 38:90-97. [DOI: 10.3928/1081597x-20211112-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Zhang D, Qin X, Zhang H, Li L. Time-varying regularity of changes in biomechanical properties of the corneas after removal of anterior corneal tissue. Biomed Eng Online 2021; 20:113. [PMID: 34801040 PMCID: PMC8606087 DOI: 10.1186/s12938-021-00948-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 11/03/2021] [Indexed: 11/13/2022] Open
Abstract
Background The corneal biomechanical properties with the prolongation of time after corneal refractive surgery are important for providing a mechanical basis for the occurrence of clinical phenomena such as iatrogenic keratectasia and refractive regression. The aim of this study was to explore the changes of corneal elastic modulus, and stress relaxation properties from the 6-month follow-up observations of rabbits after a removal of anterior corneal tissue in simulation to corneal refractive surgery. Methods The anterior corneal tissue, 6 mm in diameter and 30–50% of the original corneal thickness, the left eye of the rabbit was removed, and the right eye was kept as the control. The rabbits were normally raised and nursed for 6 months, during which corneal morphology data, and both of corneal hysteresis (CH) and corneal resistance factor (CRF) were gathered. Uniaxial tensile tests of corneal strips were performed at months 1, 3, and 6 from 7 animals, and corneal collagen fibrils were observed at months 1, 3, and 6 from 1 rabbit, respectively. Results Compared with the control group, there were statistical differences in the curvature radius at week 2 and month 3, and both CH and CRF at months 1, 2, and 6 in experiment group; there were statistical differences in elastic modulus at 1, 3, and month 6, and stress relaxation degree at month 3 in experiment group. The differences in corneal elastic modulus, stress relaxation degree and the total number of collagen fibrils between experiment and control groups varied gradually with time, and showed significant changes at the 3rd month after the treatment. Conclusions Corneas after a removal of anterior corneal tissue undergo dynamic changes in corneal morphology and biomechanical properties. The first 3 months after treatment could be a critical period. The variation of corneal biomechanical properties is worth considering in predicting corneal deformation after a removal of anterior corneal tissue.
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Affiliation(s)
- Di Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Xiao Qin
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. .,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
| | - Lin Li
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. .,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
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Stewart S, Liu YC, Lin MTY, Mehta JS. Clinical Applications of In Vivo Confocal Microscopy in Keratorefractive Surgery. J Refract Surg 2021; 37:493-503. [PMID: 34236907 DOI: 10.3928/1081597x-20210419-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To review the contribution of in vivo confocal microscopy (IVCM) to the understanding of corneal wound healing following refractive surgery, and its role in the diagnosis and management of complications arising from keratorefractive procedures. METHODS Review of the basic science and clinical literature relating to the study of keratorefractive surgical procedures using IVCM. RESULTS Extensive research using IVCM has generated a comprehensive understanding of tissue responses after corneal refractive surgery. Epithelial thickness and stromal keratocyte density can be quantified postoperatively and studied longitudinally. Corneal nerve loss and subsequent reinnervation has been characterized and differs significantly between laser refractive techniques. IVCM has also been used to study complications arising from postoperative inflammation (diffuse lamellar keratitis, central toxic keratopathy, ring keratitis, and ectasia), infection (microbial keratitis), and neuropathy (dry eye and neuralgia). This imaging technique can have a critical role in the diagnosis of these complications and subsequent monitoring of treatment response. Manual processing of IVCM images is time-consuming and there may be significant interobserver and intraobserver variability with poor repeatability. However, increasing automation and the use of artificial intelligence is improving the speed and accuracy of image analysis. CONCLUSIONS IVCM has historically been confined to a research setting because image capture and subsequent processing was extremely labor intensive. However, advances in both hardware and software capabilities promise to allow the use of IVCM in routine clinical practice. Real-time evaluation of the cornea at a cellular level will be particularly useful in patients with inflammatory, infectious, or neuropathic complications of keratorefractive surgery. [J Refract Surg. 2021;37(7):493-503.].
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