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The three-dimensional images of MTF values ((a) before procedure; (b) 1 week after procedure; (c) 1 month after procedure; (d) 3 months after SMILE procedure).
Source publication
Purpose. To investigate the visual quality after SMILE and Femto-LASIK. Methods. About 123 eyes from 63 patients were enrolled in this study. The parameters were measured preoperatively and 1 week, 1 month, and 3 months postoperatively using Sirius System. Results. The MTF curve increase slightly from low to high frequency at 3 mm and 6 mm pupil di...
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most frequently performed and successful
operations in medicine. The possible sequelae
of LRS include dry eye syndrome, blurred
vision, glare, and night vision disturbance that
are usually transient, but sometimes persist.
Psychiatric complications such as psychosis,
depression, suicidal ideation, attemp...
Citations
... These findings were consistent with the literature. [3,18,19] We hypothesize that in addition to the existence of a flap, a higher reduction in EOZ diameter may be another key factor responsible for increased spherical aberration and RMS following F-LASIK compared to SMILE because of the close relationship between the optical zone and visual quality. ...
... We also observed that SMILE caused fewer Q increases than F-LASIK. [18] This may help to explain, at least partially, why the EOZ attained with SMILE was much lower than with F-LASIK. ...
Purpose
To compare the effective optical zones (EOZs) of small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (F-LASIK) by utilizing topographic methods on the tangential curvature difference map at postoperative 1 year and to identify parameters linked to the EOZ alterations following both surgeries.
Methods
Myopic patients who underwent SMILE or F-LASIK were included in the study. Patients with refractive error greater than −9.0 D sphere or −0.50 D of astigmatism were excluded from the study. EOZs were measured at postoperative 1 year by using the tangential curvature difference map of the Scheimpflug tomography system. Correlations between the EOZ alterations and relevant parameters were assessed.
Results
In total, 59 eyes in the SMILE group and 65 eyes in the F-LASIK group were assessed. The decrease in EOZ compared with the programmed optical zone was significantly higher in the F-LASIK group ( P < 0.001). The increase in corneal asphericity was significantly relevant to the decrease in EOZin both groups according to the multiple regression analysis ( P < 0.001, B/95% CI: 0.62/0.34 and 0.90, standardized-Beta: 0.587 for the SMILE group; P < 0.001, B/95% CI: 0.74/0.41 and 1.07, standardized-Beta: 0.631 for the F-LASIK group).
Conclusion
The EOZ decreased 1 year after both SMILE and F-LASIK. The SMILE group showed less EOZ reduction than F-LASIK patients relative to the programmed optical zone. The decrease in EOZ was correlated with the increase in corneal asphericity in both groups.
... More than 6 million people have been reported to undergo small incision lenticule extraction (SMILE) globally since 2011, among which more than half were performed in China [3]. Several factors have been shown to potentially affect visual function postoperatively, including surgery types [4,5], higher-order aberration [4,6], pupil size [7], and dry eye disease (DED) [8,9]. ...
The aim of this study was to explore the impact of dry eye disease (DED) on the uncorrected distance visual acuity (UDVA) and refractive status after small incision lenticule extraction (SMILE). This prospective cohort study enrolled 29 patients (DED group, 11 eyes; non-DED group, 18 eyes) who underwent SMILE in our center from July to September 2022. The examinations on DED, refractive status and UDVA were performed before surgery, and on day 7 and 20 after surgery. The results showed that on day 20 after SMILE, subjects in the non-DED group reported greater changes of ocular surface disease index value increase and tear-film breakup time reduction compared to baseline than those in the DED group (p < 0.001 and p = 0.048, respectively). Compared to preoperative status, DED patients had greater improvements of UDVA and better optometric outcomes on day 20 after surgery than non-DED subjects (p = 0.008 and 0.026, respectively). Multiple linear regression analysis showed age, contact lens daily wearing time, and tear meniscus height before surgery were of the highest value to predict UDVA on day 20 after SMILE in contact lens wearers (p = 0.006, 0.010 and 0.043, respectively). In conclusion, preoperative tear function could affect UDVA after SMILE. The impact of DED on UDVA and refraction should be taken into consideration before surgery.
... In this study the UDVA improved so much in both groups [13,14] . We noticed fast improvement of UDVA in lasik group compared to smile group starting from the second postoperative day. ...
... 5 Many clinical studies have evaluated the pre-and post-operative effect on straylight after refractive surgery. The results were consistent: post-operative straylight values in myopes after laser-assisted in situ keratomileusis (LASIK)/ laser-assisted epithelial keratomileusis (LASEK) [10][11][12][13][14] or after phakic intraocular lens (pIOL) implantation 15,16 were on average slightly lower than pre-operative straylight measurements. Assumptions were made that these improvements are the result of ill-tolerated contact lenses preoperatively. ...
The effect of cataract and other media opacities on functional vision is typically assessed clinically using visual acuity. However, from both clinical and basic research, it has become evident that straylight (the functional result of light scattering in the eye) must be considered also as significant part of quality of vision. The optical basis of acuity and scatter are quite different. Acuity (and contrast sensitivity) depend on the refractile structure of the eye optics (refractive error and aberrations), whereas straylight mostly depends on the presence of light scattering particles of microscopic size. It must be noted that the first aspect is of global nature; the refractile structure concerns all light entering the pupil, whereas light scattering is of local nature, concerning only part of the light entering the pupil. The other part is under the influence of the refractile structure only. The subject of this presentation is the potential link between these two phenomena, and their functional counterparts: is visual acuity in cataract and other media opacities related to straylight? On the other hand, is straylight or its measurement under the influence of refractile errors, more in particular for myopic eyes?
Potential interdependence between acuity and straylight was addressed for normal eyes by manipulating refractive correction with plus lenses. No effect on measured straylight values was found. Also statistically, little relation between straylight and acuity exists in the normal population, in concordance with expectation from theoretical modelling. Visual acuity losses with cataract and other media opacities are not due to straylight, but caused by aberrations and micro-aberrations. Straylight defines disability glare, and causes symptoms of glare, haloes, hazy vision etc. Overall, visual acuity and straylight are rather independent aspects of quality of vision.
For myopic eyes, literature has shown a clear interdependence (Rozema et al. IOVS 2010 pp 2795–2799). To understand this finding, straylight values were measured with the C-Quant (Oculus Optikgeräte, GmbH, Wetzlar, Germany) in (1) near-emmetropic eyes (n = 30) with various negative powered refractive lenses and in (2) myopic eyes (n = 30) corrected with prescribed eyeglasses and contact lenses. The straylight measurements in each group were compared in the different conditions. In the near-emmetropic group, a significant effect (p < 0.001) of each added negative diopter was found to increase straylight values with 0.006 log-units. In the second group, no significant correlation with type of correcting lens was found on straylight values. So, refractive correction with high minus power (contact) lenses result in subtle increase of straylight values. These changes are relatively small though.
... [30] It is reported to achieve similar optical effects as femtosecond LASIK with excellent postoperative outcomes. [36] In the SMILE technique, there are no fluctuations in the intraocular pressure as in LASIK. Thus, one can assume that the incidence of PVD following SMILE would be lesser as compared to LASIK or femtosecond LASIK. ...
Some degenerations involving the peripheral retina can result in a rhegmatogenous retinal detachment. Currently, there are no clear guidelines for retinal screening and/or management of these peripheral retinal degenerations in patients with or without recent onset posterior vitreous detachment or in those prior to refractive surgery or intraocular procedures. This article aims to provide a set of recommendations for the screening and management of peripheral retinal degenerations based on a common consensus obtained from an expert panel of retinal specialists.
... Thereinto, the optical quality is believed to be the most important indicator [10]. According to most of clinical data, the optical quality after SMILE is generally better than that after FS-LASIK [11][12][13]. However, most of these data are obtained from the patients with low and moderate myopia. ...
... It might be related to the different refractive diopters, inspection equipments and assessing parameters, detecting conditions, surgery equipments and procedures, surgeons, etc. For example, by using Sirius System, Jin et al. found that SMILE showed better optical quality than FS-LASIK at larger pupil diameter [13]. Yet no observations of optical quality at different pupil diameters were made in our study. ...
Background:
To compare the correction effect and optical quality after small-incision lenticule extraction (SMILE) and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia.
Methods:
51 high myopia eyes after SMILE and 49 high myopia eyes after FS-LASIK were enrolled and divided into two groups retrospectively. The OQAS and iTrace analyzer were used for optical quality inspection. Between the two groups the spherical equivalent (SE), astigmatism, uncorrected distant visual acuity (UDVA), strehl ratio (SR), modulation transfer function cutoff frequency (MTF cutoff), objective scatter index (OSI) and wavefront aberrations were analyzed and compared before surgery and at 1, 6 and 12 months after surgery.
Results:
After the operation: (1) SE and astigmatism declined and UDVA increased significantly in both groups, and UDVA was better after SMILE than FS-LASIK. (2) SR and MTF cutoff reduced and OSI increased significantly after SMILE and FS-LASIK. SR and MTF cutoff were significantly higher after SMILE than FS-LASIK. OSI was significantly lower after SMILE than FS-LASIK. (3) The total wavefront aberration, total low-order wavefront aberration, defocus and astigmatism aberration as well as trefoil aberration reduced significantly in both groups. The total high-order wavefront aberration increased significantly after FS-LASIK. The spherical and coma aberration increased significantly in both groups. The total high-order wavefront aberration and coma aberration at 1 month were higher after FS-LASIK than SMILE.
Conclusion:
The optical quality descended after SMILE and FS-LASIK. SMILE was superior to FS-LASIK at the correction effect and optical quality for high myopia. The combination of OQAS and iTrace analyzer is a valuable complementary measurement in evaluating the optical quality after the refractive surgery.
Trial registration:
This is a retrospective study. This research was approved by the ethics committee of Xiangya Hospital and the IRB approval number is 201612074.
... It is minimally invasive, with less postoperative reduction in corneal sensitivity and lower degree of surgically induced spherical aberration. Several studies have compared the efficacy and safety of SMILE vs FS-LASIK [6][7][8][9] . In the current study, we aimed to compare the outcomes of topography-guided FS-LASIK and SMILE for myopia and myopic astigmatism in terms of objective and subjective quality of vision measured by corneal higher-order aberrations (HOAs) and contrast sensitivity (CS). ...
Aim:
To compare the quality outcomes of vision at early phase after topography-guided femtosecond laser-assisted in situ keratomileusis (FS-LASIK-CV) and small incision lenticule extraction (SMILE) in treatment of myopia and myopic astigmatism.
Methods:
Retrospective comparative analysis of 49 patients that underwent FS-LASIK (n=23) or SMILE (n=26) procedure for myopia and myopic astigmatism between April and September in 2019. Pre- and postoperative uncorrected visual acuity (UCVA), spherical equivalent refraction (SEQ), cylindrical refraction, contrast sensitivity function (CSF), and corneal higher-order aberrations (HOAs) were evaluated. Independent t-test was used for inter-group comparison, while repeated measures ANOVA was used to analyze changes at different time points.
Results:
In both groups, 100% of the eyes obtained a UCVA of 20/20 or better at 1wk, 1, and 3mo postoperatively. At 1d and 3mo postoperatively, UCVA was better in FS-LASIK-CV group than in SMILE group. At 1wk postoperatively, SEQ was lower in SMILE group than in FS-LASIK-CV group (P=0.006). At 3mo postoperatively, the SEQ reached target refraction in both groups. The residual astigmatism was reduced in both groups without intergroup difference (P>0.05). At 3mo postoperatively, the spherical aberration and coma under 6 mm pupil size were higher than preoperative levels in both groups (P<0.05). However, the increase in the corneal HOAs in the FS-LASIK-CV group was less than the SMILE group (P<0.05). At 3mo postoperatively, the logCS were better than preoperative levels under scotopic conditions without glare and scotopic conditions with glare in both groups (P<0.05). At 1 and 3mo postoperatively, under scotopic conditions without glare and scotopic conditions with glare, FS-LASIK-CV group showed more improvement in logCS at two spatial frequencies (12.0 c/d and 18.0 c/d; P<0.05).
Conclusion:
Both FS-LASIK-CV and SMILE demonstrate to be safe, effective, and predictable in treatment of myopia and myopic astigmatism. Early postoperative improvement in UCVA and CSF at high spatial frequency under scotopic conditions were better after FS-LASIK-CV than SMILE.
... Previous studies have found that although there is a transient decrease in intraocular scattering and optical quality in the early period after femtosecond lenticule extraction (FLEx) and SMILE, these negative changes gradually recover and are maintained at a stable level [25][26][27]. Jin et al. compared the optical quality between SMILE and FS-LASIK in which they analyzed the MTF curve and SR using the SIRIUS corneal topography system (SCHWIND eyetech-solutions GmbH, Kleinostheim, Germany) and concluded that while both two refractive procedures showed a comparable great improvement in optical quality at 3 mm pupil diameter, but better optical quality was observed at larger pupil diameter (6 mm) in the SMILE group, which might be beneficial for night vision [28]. In the current study, optical quality and intraocular scattering data were measured by a double-pass system at 6 months postoperatively. ...
Introduction:
The aim of this study was to compare the functional optical zone (FOZ) after correction of high myopic astigmatism and low myopic astigmatism by small-incision lenticule extraction (SMILE).
Methods:
In this prospective study, 30 patients who received SMILE for high myopic astigmatism correction (cylinderical diopters ≤ - 2.0D) were enrolled in the high astigmatism group (HA). The control group comprised 40 patients who underwent SMILE for low myopic astigmatism correction (LA; cylinderical diopters ≥ - 0.5D). FOZ was delineated as the area outlined by a change of 0.5D relative to the power at the corneal vertex on the total corneal refractive power map. An ellipse-fitting program (MatLab) was used to calculate some parameters of the FOZ. Visual quality evaluations were also conducted, including evaluations of wavefront aberrations, optical quality, and intraocular scattering, and completion of a quality of life questionnaire. All of the right eyes were analyzed in the study.
Results:
The preoperative average treatment spherical equivalent (- 5.77 ± 1.86D vs. - 6.49 ± 1.49D; P = 0.074), lenticule thickness (120.87 ± 23.27 μm vs. 118.53 ± 21.66 μm; P = 0.666), and programmed optical zone (6.58 ± 0.17 mm vs. 6.65 ± 0.18 mm; P = 0.104) were comparable between the HA and LA groups. The long axes (6.99 ± 1.14 mm vs. 5.32 ± 0.61 mm; P < 0.001), short axes (4.66 ± 0.96 mm vs. 4.23 ± 0.64 mm; P = 0.047), and area (25.90 ± 8.03 mm2 vs. 17.92 ± 4.36 mm2; P < 0.001) of the FOZ were significantly larger in the HA group than in the LA group. The centration of the FOZ were comparable between the two groups (0.62 ± 0.25 mm vs. 0.70 ± 0.25 mm; P = 0.194). Postoperative spherical aberration was lower in the HA group than in the LA group (0.07 ± 0.05 μm vs. 0.14 ± 0.10 μm; P = 0.001). There was no significant difference in the ocular scatter index (0.80 ± 0.46 vs. 0.73 ± 0.46; P = 0.447), modulated transfer function (MTF)cutoff (37.89 ± 9.79 cpd vs. 39.78 ± 7.45 cpd; P = 0.363), and Strehl in two dimensions (Strehl2D) ratio (0.20 ± 0.04 vs. 0.20 ± 0.04; P = 0.363) between the HA group and the LA group. There were no significant differences in the scores on quality of life between the HA and LA groups (45.88 ± 2.15 vs. 45.64 ± 1.84; P = 0.423). Correlation analysis revealed that increase in the spherical aberration was significantly correlated with the long axes, short axes and area in the FOZ in both groups.
Conclusion:
With a comparable optical design and attempted correction in SMILE, the eyes with higher myopic astigmatism correction achieved larger FOZ than the eyes with lower myopic astigmatism correction. Consequently, less spherical aberration induction was created after higher myopic astigmatism correction. This result may be associated with less corneal volume sculpted by laser for the higher astigmatism treatment, leading to fewer biochemical responses and les change in corneal aspherity. Good retinal image quality and satisfied quality of life were achieved at a comparable level in both study groups.
... [9] It is reported to achieve similar optical effects femtosecond LASIK with excellent postoperative outcomes. [23] In the SMILE technique, there are no fluctuations in the intraocular pressure as in LASIK. Thus, one can assume that the incidence of PVD following SMILE is less compared to LASIK or femtosecond LASIK. ...
The need and demand for surgical correction of refractive errors, particularly myopia, has been increasing. Degenerations involving the peripheral retina are common in myopes and can result in a rhegmatogenous retinal detachment. There are no clear guidelines for retinal screening and management of asymptomatic retinal degenerations prior to refractive surgery or for follow-up of these patients. This article aims to provide a set of guidelines for the management of retinal degenerations in eyes undergoing refractive surgeries.
... 5 Many clinical studies have evaluated the pre-and post-operative effect on straylight after refractive surgery. The results were consistent: post-operative straylight values in myopes after laser-assisted in situ keratomileusis (LASIK)/ laser-assisted epithelial keratomileusis (LASEK) [10][11][12][13][14] or after phakic intraocular lens (pIOL) implantation 15,16 were on average slightly lower than pre-operative straylight measurements. Assumptions were made that these improvements are the result of ill-tolerated contact lenses preoperatively. ...
Purpose
To investigate the effect of refractive correction on straylight.
Patients and methods
Straylight values were measured with the C-Quant (Oculus Optikgeräte, GmbH, Wetzlar, Germany) in 1) near-emmetropic eyes (n=30) with various negative powered refractive lenses and in 2) myopic eyes (n=30) corrected with prescribed eyeglasses and contact lenses. The straylight measurements in each group were compared in the different conditions.
Results
In the near-emmetropic group, a significant effect (p<0.001) of each added negative diopter was found to increase straylight values with 0.006 log-units. In the second group, no significant correlation with type of correcting lens was found on straylight values.
Conclusion
Refractive correction with high minus power (contact) lenses result in subtle increase of straylight values. These changes are relatively small and do not lead to visual disability in a clinical setting.
