Evolution of corneal thickness and optical density after laser in situ keratomileusis versus small incision lenticule extraction for myopia correction

PurposeTo compare the thickness and stromal optical density (OD) evolution of the flap and cap after femtosecond (FS-LASIK; Visumax) and small incision lenticule extraction (SMILE), respectively, for myopia correction.MethodsA prospective study comprising 78 eyes (n=39 per group) was performed. Anterior segment optical coherence tomography (MS39) images were collected at each postoperative visit (1 day, 1 week and 1 and 3 months) and flap/cap thicknesses were measured. Using ImageJ software, three regions were defined to measure OD (in grayscale units: flap/cap stroma, residual stromal bed (RSB) and all stroma (including flap/cap-stroma, surgical interface and RSB).ResultsMean central thickness significantly increased during the 3-month follow-up in both LASIK (5.43±4.23 μm; p=0.0118) and SMILE (2.76±5.61 μm; p=0.0118), with differences between both techniques statistically significant (p=0.020). All OD values showed a statistically significant reduction during SMILE follow-up: cap 48.96±5.55 versus 44.95±5.41 (p=0.19×10−6), RSB 50.26±7.06 versus 45.42±7.53 (p=0.00005), total stroma 50.34±6.49 versus 45.46±6.96 (p=0.5×10−5) at 1 day and 3 months, respectively, whereas no statistically significant changes were found during LASIK follow-up. No significant differences were observed in OD values between both techniques at any time point, although SMILE showed a tendency for higher OD values than LASIK within the first postoperative month. Visumax presented a tendency for thicker caps than target (11.48±7.85 μm), but not for flaps (2.73±8.93 μm) (p=0.00003).ConclusionsBoth LASIK flaps and SMILE caps show a significant postoperative rethickening. SMILE corneas present higher optical densities than LASIK corneas in the early postoperative period, with a significant decrease thereafter and up to 3 months. These findings correlate with the delayed visual recovery observed after SMILE.

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Short-Term Changes in the Anterior Segment and Retina after Small Incision Lenticule Extraction

10.21203/rs.3.rs-20459/v3 ◽

2020 ◽

Author(s):

Yanwei Chen ◽

Huaping Liao ◽

Yue Sun ◽

Xi Shen

Keyword(s):

Layer Thickness ◽

Optic Disc ◽

Corneal Thickness ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Vessel Density ◽

Small Incision Lenticule Extraction ◽

Short Term ◽

Small Incision ◽

Lenticule Extraction

Abstract Background: To analyse short-term changes in the anterior segment and retina after small incision lenticule extraction (SMILE).Methods: Patients with myopia scheduled for SMILE were recruited from Ruijin Hospital, Shanghai, China. Basic patient information such as age, sex, and refractive errors was recorded. Ocular measurements were taken before surgery, and 1 day and 1 week after surgery; they included axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), pupil diameter (PD), macular thickness (MT), ganglion cell layer thickness (GCL), retinal nerve fiber layer thickness (RNFL), choroidal thickness (CT), macular vessel density, and optic disc vessel density.Results: Sixty-one eyes of 31 patients were selected for this study. AL, CCT, ACD, and postoperative PD were significantly reduced (p<0.05), while LT was thickened after surgery (p<0.05). MT at the fovea decreased 1 day and 1 week after surgery (p<0.05). GCL showed no significant changes after surgery. RNFL was unchanged 1 day after surgery, but the inferior sector was thickened 1 week after surgery. CT was thicker at the fovea 1 day after surgery and 1.0 mm from the fovea in the nasal sector 1 week after surgery. Macular vessel density was significantly decreased 1 day after surgery and most recovered in 1 week. Optic disc vessel density decreased at the peripapillary part 1 day after surgery and recovered after 1 week. 𝜟ACD and 𝜟LT showed no significant correlation 1 day after surgery. 𝜟ACD was negatively correlated with 𝜟LT and sphere 1 week after surgery (r=-0.847, p<0.000; r=-0.398, p=0.002). 𝜟LT was positively correlated with the sphere 1 week after surgery (r=0.256, p=0.048).Conclusion: The anterior segment was the most affected, while the retina also underwent changes with regard to MT, RNFL, CT, macular vessel density, and peripapillary vessel density.

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Short-term changes in the anterior segment and retina after small incision lenticule extraction

BMC Ophthalmology ◽

10.1186/s12886-020-01668-7 ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Yanwei Chen ◽

Huaping Liao ◽

Yue Sun ◽

Xi Shen

Keyword(s):

Layer Thickness ◽

Optic Disc ◽

Corneal Thickness ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Vessel Density ◽

Small Incision Lenticule Extraction ◽

Short Term ◽

Small Incision ◽

Lenticule Extraction

Abstract Background To analyse short-term changes in the anterior segment and retina after small incision lenticule extraction (SMILE). Methods Patients with myopia scheduled for SMILE were recruited from Ruijin Hospital, Shanghai, China. Basic patient information such as age, sex, and refractive errors was recorded. Ocular measurements were taken before surgery, and 1 day and 1 week after surgery; they included axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), pupil diameter (PD), macular thickness (MT), ganglion cell layer thickness (GCL), retinal nerve fiber layer thickness (RNFL), choroidal thickness (CT), macular vessel density, and optic disc vessel density. Results Sixty-one eyes of 31 patients were selected for this study. AL, CCT, ACD, and postoperative PD were significantly reduced (p < 0.05), while LT was thickened after surgery (p < 0.05). MT at the fovea decreased 1 day and 1 week after surgery (p < 0.05). GCL showed no significant changes after surgery. RNFL was unchanged 1 day after surgery, but the inferior sector was thickened 1 week after surgery. CT was thicker at the fovea 1 day after surgery and 1.0 mm from the fovea in the nasal sector 1 week after surgery. Macular vessel density was significantly decreased 1 day after surgery and most recovered in 1 week. Optic disc vessel density decreased at the peripapillary part 1 day after surgery and recovered after 1 week. ΔACD and ΔLT showed no significant correlation 1 day after surgery. ΔACD was negatively correlated with ΔLT and sphere 1 week after surgery (r = − 0.847, p < 0.000; r = − 0.398, p = 0.002). ΔLT was positively correlated with the sphere 1 week after surgery (r = 0.256, p = 0.048). Conclusion The anterior segment was the most affected, while the retina also underwent changes with regard to MT, RNFL, CT, macular vessel density, and peripapillary vessel density.

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Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2018-312140 ◽

2018 ◽

Vol 103 (4) ◽

pp. 565-568 ◽

Cited By ~ 15

Author(s):

Tian Han ◽

Ye Xu ◽

Xiao Han ◽

Li Zeng ◽

Jianmin Shang ◽

...

Keyword(s):

Visual Acuity ◽

Femtosecond Laser ◽

Laser In Situ Keratomileusis ◽

Small Incision Lenticule Extraction ◽

Small Incision ◽

Lenticule Extraction ◽

Myopic Astigmatism

AimsTo 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.MethodsIn 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.ResultsNo 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).ConclusionLong-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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Effect of Intraoperative Corneal Stromal Pocket Irrigation in Small Incision Lenticule Extraction

BioMed Research International ◽

10.1155/2015/928608 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Yu-Chi Liu ◽

Lasitha Jayasinghe ◽

Heng Pei Ang ◽

Nyein Chan Lwin ◽

Gary Hin Fai Yam ◽

...

Keyword(s):

Corneal Thickness ◽

Anterior Segment ◽

Histological Section ◽

The Other ◽

Lamellar Thickness ◽

Small Incision Lenticule Extraction ◽

Small Incision ◽

Lenticule Extraction

This study aimed at evaluating the effect of intraoperative corneal pocket irrigation in small incision lenticule extraction (SMILE) and compares it to that in femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Sixteen rabbit eyes underwent a SMILE procedure, with 8 eyes having corneal pocket irrigation, while the other 8 eyes were without irrigation. Another 16 eyes underwent a FS-LASIK procedure for comparison, with 8 eyes having flap irrigation, while the other 8 eyes were without irrigation. The results showed that the changes in the total corneal thickness, anterior and posterior lamellar thickness, measured by the anterior segment optical coherence tomography, were comparable between the SMILE with and without irrigation groups, suggesting that the irrigation did not lead to significant changes in the corneal thickness. However, at postoperative 8 hours, in vivo confocal microscopy showed that the interface reflectivity in the SMILE with irrigation group was significantly higher than that in other three groups. The presence of interface fluid was further confirmed by the identification of fluid pockets with undulated collagen shown on histological section in the post-SMILE with irrigation eyes. Our findings might contribute to the occurrence of post-SMILE delayed immediate visual quality recovery and further clinical study is required.

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Short-Term Changes in the Anterior Segment and Retina after Small Incision Lenticule Extraction

10.21203/rs.3.rs-20459/v2 ◽

2020 ◽

Author(s):

Yanwei Chen ◽

Huaping Liao ◽

Yue Sun ◽

Xi Shen

Keyword(s):

Layer Thickness ◽

Optic Disc ◽

Corneal Thickness ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Vessel Density ◽

Small Incision Lenticule Extraction ◽

Short Term ◽

Small Incision ◽

Lenticule Extraction

Abstract Background: To analyse short-term changes in the anterior segment and retina after small incision lenticule extraction (SMILE). Methods: Patients with myopia scheduled for SMILE were recruited from Ruijin Hospital, Shanghai, China. Basic patient information such as age, sex, and refractive errors was recorded. Ocular measurements were taken before surgery, and 1 day and 1 week after surgery; they included axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), pupil diameter (PD), macular thickness (MT), ganglion cell layer thickness (GCL), retinal nerve fiber layer thickness (RNFL), choroidal thickness (CT), macular vessel density, and optic disc vessel density. Results: Sixty-one eyes of 31 patients were selected for this study. AL, CCT, ACD, and postoperative PD were significantly reduced (p<0.05), while LT was thickened after surgery (p<0.05). MT at the fovea decreased 1 day and 1 week after surgery (p<0.05). GCL showed no significant changes after surgery. RNFL was unchanged 1 day after surgery, but the inferior sector was thickened 1 week after surgery. CT was thicker at the fovea 1 day after surgery and 1.0 mm from the fovea in the nasal sector 1 week after surgery. Macular vessel density was significantly decreased 1 day after surgery and most recovered in 1 week. Optic disc vessel density decreased at the peripapillary part 1 day after surgery and recovered after 1 week. 𝜟ACD and 𝜟LT showed no significant correlation 1 day after surgery. 𝜟ACD was negatively correlated with 𝜟LT and sphere 1 week after surgery (r=-0.847, p<0.000; r=-0.398, p=0.002). 𝜟LT was positively correlated with the sphere 1 week after surgery (r=0.256, p=0.048). Conclusion: The anterior segment was the most affected, while the retina also underwent changes with regard to MT, RNFL, CT, macular vessel density, and peripapillary vessel density.

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Small incision lenticule extraction (SMILE) combined with allogeneic intrastromal lenticule inlay for hyperopia with astigmatism

PLoS ONE ◽

10.1371/journal.pone.0257667 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0257667

Author(s):

Jing Zhang ◽

Yuehua Zhou

Keyword(s):

Visual Acuity ◽

Repeated Measures ◽

Anterior Segment ◽

Corneal Stroma ◽

Small Incision Lenticule Extraction ◽

Small Incision ◽

Lenticule Extraction ◽

One Year ◽

Post Hoc

Purpose To quantitatively evaluate outcomes after small incision lenticule extraction (SMILE) combined with allogeneic intrastromal lenticule inlay for hyperopia with astigmatism. Methods It’s a retrospective cohort study. Twenty-four eyes of 15 patients with more than 0.75 diopters (D) of astigmatism in hyperopic eyes were enrolled in this study. The hyperopic eye with astigmatism was first treated with SMILE to correct astigmatism; then a lenticule was extracted from a donor myopic eye and subsequently implanted into the hyperopic eye with astigmatism. Patients were examined preoperatively and 1 day, 1 week, 1,3 months and 1 year after surgery. The main outcome measures were the uncorrected and corrected distance visual acuity (UDVA and CDVA), uncorrected near visual acuity (UNVA), spherical equivalent (SE), corneal topography, anterior segment optical coherence topography (OCT) and ocular response analyzer (ORA) parameters: corneal hysteresis (CH) and corneal resistance factor (CRF). Repeated–measures analyses of variance (ANOVA) and post hoc tests were used to analyze data of different follow-up visits. Results The mean preoperative cylinder was 1.95±1.04(D). The UDVA (from 0.37±0.23 to 0.09±0.09), UNVA (from 0.49±0.21 to 0.08±0.06), SE (from +7.42±3.12 to -0.75±0.79) and astigmatism (+1.95±1.04 to -0.65±0.63) postoperatively were obviously better than those before surgery. Five eyes (26.3%) gained one line of CDVA, and 3 eyes (15.8%) gained two lines of CDVA one year after surgery compared with preoperative levels. The average corneal curvature was changed from (43.19±4.37) D to (49.19±3.87) D one year after surgery. The anterior segment OCT images of corneas with lenticule inlays at each follow-up visit showed that the implanted lenticule was shaped like a crescent in the corneal stroma. The CH and CRF didn’t change significantly after surgery (p = 0.189 and p = 0.107respectively). Conclusions SMILE combined with intrastromal lenticule inlay can be used to correct high hyperopia with astigmatism with good safety, efficacy and reproducibility.

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Short Term Changes in Anterior Segment and Retina After Small Incision Lenticule Extraction

10.21203/rs.3.rs-20459/v1 ◽

2020 ◽

Author(s):

Yanwei Chen ◽

Huaping Liao ◽

Yue Sun ◽

Xi Shen

Keyword(s):

Layer Thickness ◽

Optic Disc ◽

Pearson Correlation ◽

Corneal Thickness ◽

Anterior Segment ◽

Vessel Density ◽

Small Incision Lenticule Extraction ◽

Short Term ◽

Small Incision ◽

Lenticule Extraction

Abstract Purpose: To analyze changes of the anterior segment and retina after small incision lenticule extraction (SMILE) in the short term.Methods: Myopia patients scheduled for SMILE were recruited in Ruijin Hospital, Shanghai, China. Basic information of patients such as age, gender, and refractive errors was recorded. Ocular measurements were taken before surgery, 1 day and 1 week after surgery, including axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), pupil diameter (PD), macular thickness (MT), ganglion cell layer thickness (GCL), retinal nerve fiber layer thickness (RNFL), choroidal thickness (CT), macular vessel density, optic disc vessel density. Results of postoperative were compared to baseline, respectively, with paired student t test, and the results were considered statistically significant when p<0.05. Correlations between sphere and changes of ACD (𝜟ACD) and LT (𝜟LT) were analyzed with the Pearson correlation coefficient.Results: 61 eyes of 31 patients were selected for this study. AL, CCT, ACD, and PD postoperative were significantly reduced (p<0.05), while LT was thickened after surgery (p<0.05). MT at the fovea decreased on 1 day and 1 week after surgery (p<0.05). GCL was no statistical changes after surgery. RNFL was unchanged 1 day after surgery, but the inferior sector was thickened 1 week after surgery. CT was observed thicker at fovea 1 day after surgery and 1.0mm from the fovea in nasal 1 week after surgery. Macular vessel density was significantly decreased on 1 day after surgery and most recovered in 1 week. Optic disc vessel density decreased at the peripapillary part on 1 day after surgery and recovered in 1 week. 𝜟ACD and 𝜟LT were found no significant correlation on 1 day after surgery. 𝜟ACD was negatively correlated with 𝜟LT and sphere on 1 week after surgery (r=-0.847, p<0.000; r=-0.398, p=0.002). 𝜟LT was positively correlated with the sphere on 1 week after surgery (r=0.256, p=0.048).Conclusion: Anterior segment was the most influenced while the retina was also impacted in MT, RNFL, CT, macular vessel density, and peripapillary vessel density.

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Intraocular pressure changes and corneal biomechanics after hyperopic small-incision lenticule extraction

10.21203/rs.2.18089/v2 ◽

2020 ◽

Author(s):

Dan Fu ◽

Meiyan Li ◽

Michael C. Knorz ◽

Shengsheng Wei ◽

Jianmin Shang ◽

...

Keyword(s):

Intraocular Pressure ◽

Linear Mixed Model ◽

Corneal Thickness ◽

Corneal Biomechanics ◽

Ocular Response Analyzer ◽

Small Incision Lenticule Extraction ◽

Corvis St ◽

Small Incision ◽

Lenticule Extraction

Abstract Background: We aimed to compare the intraocular pressure (IOP) measurements by a dynamic Scheimpflug analyzer (Corvis ST), a non-contact tonometer, and an ocular response analyzer after hyperopic small-incision lenticule extraction (SMILE).Methods: Thirteen patients who underwent hyperopic SMILE in one eye were enrolled prospectively. IOP and corneal biomechanical parameters were measured preoperatively and at 1 week, 1 month, and 3 months postoperatively with a non-contact tonometer (IOPNCT), Corvis ST (biomechanical corrected IOP and biomechanical corrected IOP measured with Corvis ST [bIOP]), and an ocular response analyzer (Goldmann-correlated intraocular pressure [IOPg] and cornea compensated IOP [IOPcc]). A linear mixed model was used to compare the IOP and biomechanical values among methods at each time point.Results: IOPNCT, IOPg, and IOPcc dropped significantly after surgery, with the amplitude being 3.15±0.48 mmHg, 5.49±0.94 mmHg, and 4.34±0.97 mmHg, respectively, at the last follow-up visit. IOPNCT decreased by 0.11±0.06 mmHg per µm of excised central corneal thickness. bIOP did not change significantly after surgery. Preoperatively, no difference was found among the measurements (P> 0.05). Postoperatively, IOPNCT and bIOP were higher than IOPg and IOPcc. bIOP was independent of cornea thickness at last follow-up visit, whereas it correlated significantly with corneal biomechanics similar to the other three IOP values.Conclusion: bIOP is a relative accurate measure of IOP after hyperopic SMILE.

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SMILE and Wavefront-Guided LASIK Out-Compete Other Refractive Surgeries in Ameliorating the Induction of High-Order Aberrations in Anterior Corneal Surface

Journal of Ophthalmology ◽

10.1155/2016/8702162 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

Min-jie Ye ◽

Cai-yuan Liu ◽

Rong-feng Liao ◽

Zheng-yu Gu ◽

Bing-ying Zhao ◽

...

Keyword(s):

Spherical Aberration ◽

Laser In Situ Keratomileusis ◽

Small Incision Lenticule Extraction ◽

Corneal Surface ◽

Small Incision ◽

Significant Difference ◽

Lenticule Extraction ◽

A Prospective Study ◽

High Order Aberrations

Purpose. To compare the change of anterior corneal higher-order aberrations (HOAs) after laser in situ keratomileusis (LASIK), wavefront-guided LASIK with iris registration (WF-LASIK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE).Methods. In a prospective study, 82 eyes underwent LASIK, 119 eyes underwent WF-LASIK, 88 eyes underwent FS-LASIK, and 170 eyes underwent SMILE surgery. HOAs were measured with Pentacam device preoperatively and 6 months after surgery. The aberrations were described as Zernike polynomials, and analysis focused on total HOAs, spherical aberration (SA), horizontal coma, and vertical coma over 6 mm diameter central corneal zone.Results. Six months postoperatively, all procedures result in increase of anterior corneal total HOAs and SA. There were no significant differences in the induced HOAs between LASIK and FS-LASIK, while SMILE induced fewer total HOAs and SA compared with LASIK and FS-LASIK. Similarly, WF-LASIK also induced less total HOAs than LASIK and FS-LASIK, but only fewer SA than FS-LASIK (P<0.05). No significant difference could be detected in the induced total HOAs and SA between SMILE and WF-LASIK, whereas SMILE induced more horizontal coma and vertical coma compared with WF-LASIK (P<0.05).Conclusion. FS-LASIK and LASIK induced comparable anterior corneal HOAs. Compared to LASIK and FS-LASIK, both SMILE and WF-LASIK showed advantages in inducing less total HOAs. In addition, SMILE also possesses better ability to reduce the induction of SA in comparison with LASIK and FS-LASIK. However, SMILE induced more horizontal coma and vertical coma compared with WF-LASIK, indicating that the centration of SMILE procedure is probably less precise than WF-LASIK.

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