Small Incision Lenticule Extraction Surgery Research Articles

Top 50 most-cited articles on SMILE surgery between 2010 and 2022: a correlation comparison between conventional bibliometrics and current altmetrics of research impact.

To conduct a bibliometric and altmetric analysis of the top 50 most-cited articles on small incision lenticule extraction (SMILE) surgery and assess its correlations with other metrics. The terms "small incision lenticule extraction" or "SMILE" were searched in the title, abstract, and keywords using Web of Science database. The retrieved articles (n = 927, between 2010 and 2022) were analyzed in-depth using altmetric attention scores (AAS), and traditional metrics (citation numbers of articles, impact factor of journals, and other citation-based metrics). A correlation statistics was performed with metrics. The articles' focus was examined quantitatively and the most prolific parameters were identified. Authorship network and country statistics also was examined. Citation numbers were between 491 and 45. AASs were between 26 and 0. The altmetric score correlated moderately with citation number (r = 0.44, P = 0.001) and annual mean citations (r = 0.49, P < 0.001), but correlated weakly with impact factor (r = 0.28, P = 0.045), and immediacy index (r = 0.32, P = 0.022). The most articles published from China and the most articles were published in 2014. Modern SMILE surgery was mostly compared to the older LASIK procedure. The highest authorship number of links belonged to Zhou XT. The first bibliometric and altmetric analysis of SMILE research provides novel directions for future work by showing the current research trends, prolific parameters, and zones with potential for the public's attention, providing useful information about the dissemination of scientific knowledge on SMILE in social media and to the general public.

Prediction of Early Visual Outcome of Small-Incision Lenticule Extraction (SMILE) Based on Deep Learning.

Deep learning (DL) has been widely used to estimate clinical images. The objective of this project was to create DL models to predict the early postoperative visual acuity after small-incision lenticule extraction (SMILE) surgery. We enrolled three independent patient cohorts (a retrospective cohort and two prospective SMILE cohorts) who underwent the SMILE refractive correction procedure at two different refractive surgery centers from July to September 2022. The medical records and surgical videos were collected for further analysis. Based on the uncorrected visual acuity (UCVA) at 24h postsurgery, the eyes were divided into two groups: those showing good recovery and those showing poor recovery. We then trained a DL model (Resnet50) to predict eyes with early postoperative visual acuity of patients in the retrospective cohort who had undergone SMILE surgery from surgical videos and subsequently validated the model's performance in the two prospective cohorts. Finally, Gradient-weighted Class Activation Mapping (Grad-CAM) was performed for interpretation of the model. Among the 318 eyes (159 patients) enrolled in the study, 10,176 good quality femtosecond laser scanning images were obtained from the surgical videos. We observed that the developed DL model achieved a high accuracy of 96% for image prediction. The area under the curve (AUC) value of the DL model in the retrospective cohort was 0.962 and 0.998 in the training and validation datasets, respectively. The AUC values in two prospective cohorts were 0.959 and 0.936. At the video level, the trained machine learning (ML) model (XGBoost) also accurately distinguished patients with good or poor recovery. The AUC value of the ML model was 0.998 and 0.889 in the retrospective cohort (training and test datasets, respectively) and 1.000 and 0.984 in the two prospective cohorts. We also trained a DL model which can accurately distinguish suction loss (100%), black spots (85%), and opaque bubble layer (96%). The Grad-CAM heatmap indicated that our models can recognize the area of scanning and precisely identify intraoperative complications. Our findings suggest that artificial intelligence (DL and ML model) can accurately predict the early postoperative visual acuity and intraoperative complications after SMILE surgery just using surgical videos or images, which may display a great importance for artificial intelligence in application of refractive surgeries.

Change in the corneal material mechanical property for small incision lenticule extraction surgery.

Purpose: To assess the distribution characteristics and related factors of stress-strain index (SSI) values and discuss changes in biomechanical parameters, including SSI, after small incision lenticule extraction (SMILE) surgery. Methods: This study included 253 patients who underwent SMILE (253 eyes). SSI and other biomechanical parameters were measured using corneal visualization Scheimpflug technology before and 3months after surgery. The data collected included SSI, central corneal thickness (CCT), and eight other dynamic corneal response parameters. The Kolmogorov-Smirnov test, Pearson and partial correlation analyses, and paired-sample t-tests were used for statistical analyses. Results: Both pre-op SSI and ΔSSI follow a normal distribution, while post-op SSI does not follow a normal distribution. The decline in SSI after SMILE surgery was not statistically significant, and the data dispersion of SSI after SMILE surgery was close to that before surgery (p > 0.05). No statistical correlation was noted between SSI values and age and pre-op CCT (all p > 0.05). However, both pre- and post-op SSI values decreased with increasing degree of myopia (all p < 0.05), and weakly correlated with preoperative intraocular pressure and biomechanically corrected intraocular pressure (all p < 0.05). Other biomechanical parameters changed significantly after surgery (all p < 0.001). After SMILE, the magnitude of the deformation at the highest concave, deformation ratio, and integral radius increased significantly (all p < 0.001), while the Ambrosio relational thickness horizontal, stiffness parameter A1, and Corvis biomechanical index decreased significantly (p < 0.001). Conclusion: SSI, which reflects essential corneal material attributes, differs from other corneal biomechanical parameters and remains stable before and after SMILE surgery, and can be used as an indicator to evaluate changes in corneal material properties after SMILE surgery.

SMILE lenticule versus amniotic membrane graft (AMG) augmented with platelet-rich plasma (PRP) for the treatment of perforated corneal ulcer.

To evaluate the safety and efficacy of stromal lenticule obtained from small-incision lenticule extraction (SMILE) surgery versus amniotic membrane graft (AMG) augmented with platelet-rich plasma (PRP) for the treatment of perforated corneal ulcers and compare the results between the two groups. This is a comparative retrospective study that included 40 eyes with medium-sized corneal perforations, which were classified into two equal groups of 20 eyes each; group (A) was treated with SMILE lenticule graft and group (B) was treated with AMG augmented with PRP. Pre- and postoperative evaluations were carried out using both slit-lamp (SL) examination and anterior segment optical coherence tomography (AS-OCT), including closure of perforation, complete healing, and best corrected visual acuity (BCVA). Complete closure of the perforation was achieved in both groups. However, healing was faster in the SMILE lenticule group than in the AMG with PRP group (P < 0.05). Complete healing was achieved inboth groups: 100% in SMILE lenticule group and 95% in AMG with PRP group (P > 0.05). Both groups had few insignificant complications (30% in each), which were managed. Both methods achieved adequate healing of corneal perforations within few weeks without significant complications. However, the stromal lenticule obtained from small-incision lenticule extraction (SMILE) surgery tended to be safer with faster healing than AMG with PRP.

In Vivo Evaluation of the Effects of SMILE with Different Amounts of Stromal Ablation on Corneal Biomechanics by Optical Coherence Elastography

This work aims to depth-resolved quantitatively analyze the effect of different stromal ablation amounts on the corneal biomechanical properties during small incision lenticule extraction (SMILE) using optical coherence elastography (OCE). A 4.5-MHz ultrasonic transducer was used to excite elastic waves in the corneal tissue. The OCE system combined with the antisymmetric Lamb wave model was employed to achieve a high-resolution, high-sensitivity, and depth-resolved quantitative detection of the corneal Young's modulus. Eighteen rabbits were randomly divided into three groups; each group had six rabbits. The first and second groups underwent -3D and -6D SMILE surgeries, and the third group was the control group, respectively. Young's modulus of the corneal cap and residual stromal bed (RSB) were both increased after SMILE, which shared the stress under intraocular pressure (IOP). Furthermore, the Young's modulus of both the corneal cap and RSB after 3D SMILE group were significantly lower than that in the -6D group, which indicated that the increases in the post-operative corneal Young's modulus were positively correlated with the amount of stromal ablation. The OCE system for quantitative spatial characterization of corneal biomechanical properties can provide useful information on the extent of safe ablation for SMILE procedures.

Central toxic keratopathy after small incision lenticule extraction surgery:A case report.

To report a rare case of central toxic keratopathy after small incision lenticule extraction surgery (SMILE). A 38-year-old female presented with visual loss 10 days after undergoing SMILE. Subsequently, transparent band keratopathy was protruded in the left cornea and corneal cap opacity was increased, which was accompanied by hyperopic shift and corneal thinning. The patient's condition rapidly improved with the administration of prednisolone acetate and autologous serum, with significant resolution of the transparent band keratopathy within 5 weeks of treatment initiation and subsequent complete visual recovery. Central toxic keratopathy is a severe complication after undergoing SMILE, which might be effectively treated using with steroids and autologous serum.

Effect of incision location on with-the-rule astigmatism correction after SMILE.

To explore the influence of two different incision positions of small incision lenticule extraction (SMILE) on astigmatism correction. A total of 86 eyes of 86 patients who underwent SMILE surgery were included in this retrospective study. The criteria included that the preoperative astigmatism axis to be within 165° to 180° or 5° to 15°. All eyes were divided into two groups according to the incision position. The incisions of 34 eyes were either located on the superior temporal side of the right eye or superior nasal side of the left eye (120° group), and 52 eyes were located on the superior side (90° group). Vector analysis was used to analyze pre- and postoperative 3-month astigmatism, while subgroup analysis was applied according to the preoperative astigmatism. No significant difference of preoperative parameters was found between the two groups (P > 0.05). The efficacy and safety indexes were 1.11 ± 0.16 and 1.15 ± 0.16 in the 120° group, the numbers were 1.15 ± 0.17 and 1.16 ± 0.14 in the 90° group (P = 0.629 and P = 0.871). There was no significant difference in target-induced astigmatism (TIA), TIA axis, surgically induced astigmatism (SIA) magnitude, SIA axis, distance vision (DV) magnitude, DV axis, correction index (CI), angle of error (AofE), |AofE|, magnitude of error (MofE), index of success (IOS), or flattening index (FI) between 120° group and 90° group (P > 0.05). No significant difference was found in the subgroup analysis (P > 0.05). The incision position has limited astigmatic effect, and the operation-induced astigmatism of SMILE surgery after 3 months was little.

Dynamic Visual Acuity After Small Incision Lenticule Extraction for Myopia Patients.

In the present study we compared dynamic visual acuity (DVA) of 84 eyes (for 42 adults with myopia; M age = 28.4, SD = 6.6years; males = 38.1%, females = 61.9%) at 40 and 80 degree per second (dps) before surgery with eyeglass corrections and after a surgical procedure - a small incision lenticule extraction (SMILE). Participants underwent binocular SMILE surgery with plano refraction targets. Their eyeglass-corrected binocular DVA at 40 and 80 dps was evaluated preoperatively, and their uncorrected binocular DVA was assessed post-operatively at 1week, 1month and 3months. The mean logMAR (logarithm of the minimum angle of resolution) uncorrected and corrected distance visual acuities (UDVA and CDVA) were -0.09 and -0.11 respectively, 3months postoperatively. The mean preoperative eyeglass-corrected DVAs at 40 and 80 dps were 0.141 and 0.184, respectively, and significant improvements were observed for 40 dps and 80 dps DVAs 3months postoperatively. Pearson's correlations were statistically significant between the postoperative DVAs at 3months and for both the preoperative DVA and postoperative UDVA at both 40 dps and 80 dps. The change in the DVAs at 3months were significantly associated with the preoperative DVAs at 40 dps and 80 dps. In conclusion, myopic patients' DVAs significantly improved following SMILE in comparison to corrected preoperative visual acuity when wearing eyeglasses. The post-SMILE DVA was associated with both the preoperative DVA and the postoperative UDVA.

Comparison of different correction formulas and measurement methods for the accurate determination of intraocular pressure after SMILE and FS-LASIK surgery

BackgroundTo compare the accuracy of non-contact tonometry, Pentacam, and corneal visualization Scheimpflug technology (Corvis ST) for the measurement of intraocular pressure (IOP) after small incision lenticule extraction (SMILE) or femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery.MethodsA total of 49 patients (98 eyes) undergoing FS-LASIK or SMILE surgery at West China Hospital, Sichuan University from January to March 2021 were enrolled in this prospective, comparative, self-controlled study. IOP values were measured with non-contact tonometer, Pentacam, and Corvis ST before surgery and 1 month after surgery. Pentacam-derived postoperative IOP values were corrected using five correction formulas (Ehlers, Shah, Dresden, Orssengo-Pye, and Kohlhaas), while Corvis ST-derived values were corrected using a single formula.ResultsIn the SMILE group, no significant differences were observed between the IOP values corrected with the Shah formula before and after surgery (t = 0.17, P = 0.869), whereas postoperative IOP values corrected with the other formulas were significantly different from the corresponding preoperative measurements (P < 0.05). In the FS-LASIK group, postoperative IOP values corrected with the Ehlers, Shah, or Corvis ST formulas were significantly different from the corresponding preoperative IOP measurements (P < 0.05), but no significant differences were observed between pre- and postoperative IOP values corrected with the Dresden (t = − 0.08, P = 0.941), Orssengo-Pye (t = − 0.52, P = 0.604), or Kohlhaas (t = 1.22, P = 0.231) formulas.ConclusionsPentacam’s Shah correction formula seemed to be the most appropriate method for accurately measuring postoperative IOP in patients undergoing SMILE surgery, while the Dresden, Orssengo-Pye, and Kohlhaas correction formulas of Pentacam were identified as the most reliable methods for estimating IOP in patients after FS-LASIK surgery.

Twelve-year global publications on small incision lenticule extraction: A bibliometric analysis.

PurposeTo analyze the development process of small incision lenticule extraction (SMILE) surgery in a 12-year period.MethodsWe conducted a literature search for SMILE research from 2011 to 2022 using the Science Citation Index Expanded (SCIE) of the Web of Science Core Collection (WoSCC). The VOS viewer, and CiteSpace software were used to perform the bibliometric analysis. Publication language, annual growth trend, countries/regions and institutions, journals, keywords, references, and citation bursts were analyzed.ResultsA total of 731 publications from 2011 to 2022 were retrieved. Annual publication records grew from two to more than 100 during this period. China had the highest number of publications (n = 326). Sixty-five keywords that appeared more than four times were classified into six clusters: femtosecond laser technology, dry eye, biomechanics, visual quality, complications, and hyperopia.ConclusionThe number of literatures has been growing rapidly in the past 12 years. Our study provides a deep insight into publications on SMILE for researchers and clinicians with bibliometric analysis for the first time.

Simple method of measuring ocular rotation in supine position during small incision lenticule extraction.

To introduce a novel measurement method of static cyclotorsion in small incision lenticule extraction (SMILE) and to investigate the effect of preoperative parameters on cyclotorsion and the effect of cyclotorsion on postoperative outcomes. The medical records of 242 patients and 484 eyes who underwent SMILE surgery were retrospectively reviewed. Preoperative intraocular pressure, refractive error, and corneal thickness were investigated. Refractive values and visual acuity were measured at 1d, 1, 3, and 6mo. Ocular cyclotorsion in the supine position was measured by calculating the location and angle of the incision site of the cornea in the anterior slit photograph taken after surgery. Of the total 484 eyes in 242 patients, preoperative mean spherical equivalent (SE) was -4.10±1.64 D, and the mean astigmatism was -0.82±0.74 D. Uncorrected distance visual acuity (UCVA) and SE improved significantly after the surgery. Moreover, 219 (45.2%) eyes had excyclotorsion, 235 (48.6%) eyes had incyclotorsion, and 30 (6.2%) eyes had no torsion. The right eyes tended to be excyclotorted, and the left eyes tended to be incyclotorted (P<0.01). The mean cyclotorsion was 1.18°±3.69°, and the mean absolute value of cyclotorsion was 3.14°±2.26°. The range of cyclotorsion was 0.5°-11.4°. It was found that the smaller the preoperative sphere, the higher the amount of cyclotorsion (r=0.11, P=0.016). There was no significant association between the amount of cyclotorsion and preoperative astigmatism. There was no correlation between sex, preoperative corneal thickness, preoperative intraocular pressure, amount of cyclotorsion, and direction of cyclotorsion. The ratio of right eye excyclotorsion and left eye incyclotorsion on 1d was higher than that at 1, 3, and 6mo (all P<0.01). There was no difference between the 1, 3, and 6mo results in the right and left eyes (P=0.15, P=0.16, respectively). The newly devised ocular cyclotorsion measurement method can be used to evaluate ocular cyclotorsion after SMILE. Preoperative SE is associated with the amount of cyclotorsion, however, cyclotorsion doesn't have a significant effect on the results of SMILE surgery.

Fresh Human Myopic Lenticule Intrastromal Implantation for Keratoconus Using SMILE Surgery in a Long-term Follow-up Study: Ultrastructural Analysis by Transmission Electron Microscopy.

To investigate new intrastromal histological structures that develop after myopic human lenticular implantation in keratoconus with femtosecond laser-assisted small incision lenticule extraction (SMILE) surgery using transmission electron microscopy. Sixty eyes with advanced keratoconus indicated for corneal transplantation were included in this study. Fresh myopic lenticular implants were placed in all eyes through SMILE surgery. Lenticular implants were extracted from patients with myopic refractive errors of the cornea, untreated keratoconus, and treated keratoconus following 1, 2, and 3 years of surgery. These five lenticular samples were examined under the electron microscope and compared. Disorganized and thinned collagen fibers were observed in the stroma with degenerative stromal cells (telocyte-like cells and keratocytes) in the keratoconic cornea. Apoptotic bodies and cell debris were easily observed near the disorganized fibers. In contrast, the myopic refractive error of the control and treatment groups demonstrated well-organized parallel lamellar structures. Healthy keratocytes and telocyte-like cells were observed in samples obtained 1, 2, and 3 years after lenticular implantation. Thus, telocyte-like cells may be activated by appropriate stimuli, such as stem cells, and be involved in stromal regeneration. Fresh myopic intrastromal lenticular implantation is a safe, economical, and reliable technique that leads to increased corneal thickness, improved visual acuity, and the regeneration of healthy keratocytes and telocyte-like cells that are involved in stromal regeneration. [J Refract Surg. 2022;38(8):520-528.].

Changes in effective optical zone after small-incision lenticule extraction in high myopia.

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. Corneal refractive surgery conducted in an eye hospital in southern China. This is a retrospectivecohort study. In total, 74 subjects were recruited. EOZ was measured at 3months postoperatively using vertex-based (EOZV), pupil-based (EOZP), 4mm-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. At 3months after surgery, the mean root mean square of ΔHOA, ΔComa, ΔTrefoil and ΔSA were 0.53 ± 0.27μm, 0.36 ± 0.20μm, 0.01 ± 0.84μm and 0.16 ± 0.14μm, respectively. EOZV, EOZP, EOZ4 and EOZD were 5.87 ± 0.44mm, 5.85 ± 0.45mm, 4.78 ± 0.40mm and 5.29 ± 0.27mm, respectively, which were significantly smaller than POZ 6.48 ± 0.16mm. Bland-Altman plots showed a good consistency among the four EOZs. The difference between the EOZV and EOZP was 0.02mm within the range of clinically acceptable difference. In addition, the eccentricity was positively correlated with ΔHOA, ΔComa and ΔSA. 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.

Wavefront aberrations caused by biomechanical effects after Small Incision Lenticule Extraction (SMILE) based on finite element analysis

To examine wavefront aberrations induced by biomechanical effects after Small Incision Lenticule Extraction (SMILE) surgery. The three-dimensional (3D) finite element models of the human eye were established. By loading the intraocular pressure (IOP), the displacement of the anterior and posterior surface of the cornea was calculated. Then the displacement was converted into the wavefront aberrations by wave-surface fitting. The results showed that the induced wavefront aberrations were noticeable from biomechanical effects after SMILE surgery. The induced higher-order aberrations from the anterior corneal surface included spherical aberration, y-Trefoil, and x-Tetrafoil. Spherical aberration was positively correlated with corrected diopter (D), but x-Tetrafoil and y-Trefoil remained stable. The induced wavefront aberrations from the posterior corneal surface were smaller than those from the anterior corneal surface, and some of the aberrations compensated each other. With IOP increased, defocus and x-Tetrafoil from the anterior corneal surface increased, while y-Trefoil and spherical aberration decreased. The IOP only affected defocus from the posterior corneal surface. In addition, the incision size also had a distinct impact on primary x-astigmatism and x-Trefoil from the anterior corneal surface, and it had a smaller effect on the aberrations from the posterior corneal surface. Therefore, the biomechanical effects increased residual wavefront aberrations after SMILE refractive surgery.

Impact of unintended initial dissection of the posterior plane during SMILE surgery on surgery time and visual outcomes

BackgroundTo study the impact of unintended initial dissection of the posterior plane (UIDPP) on operation time and surgical outcomes during small incision lenticule extraction (SMILE) surgery.MethodsThis was a retrospective study. Based on the SMILE procedure video, the operating eyes were assigned to the normal and UIDPP groups according to the presence or absence of UIDPP signals during surgery. The UIDPP group was further separated into early and late detection based on whether the complete dissection of the lenticule posterior plane or not. Patient's demographic data, preoperative evaluation data, operation time and postoperative outcomes were collected.ResultsSixty-six patients (66 eyes) who underwent SMILE were included, with 24 eyes with UIDPP (13 in the early detection group and 11 in the late group). The optical zone was smaller (median 6.5 vs. 6.6, P = 0.007), and the operation time was longer (median, 189.5 vs. 91.0 s, P < 0.001) in the UIDPP group compared with normal group. There were significant differences in operation time between the late detection group and early detection group (median, 489.0 vs. 139.0 s, P < 0.05) and between the late detection group and normal group (median 489.0 vs. 91.0 s, P < 0.05), while the optical zone was different only between the late detection and normal groups (median, 6.5 vs. 6.6, P < 0.05). At the one-year follow-up, UDVA was better than or equal to 20/20 in 87.5% of eyes, and 75% of eyes were within ± 0.5 D of the intended refractive target. One eye lost one Snellen line.ConclusionThe occurrence of UIDPP will significantly prolong the operation time, but not affect the recovery of long-term visual acuity after surgery. Detecting UIDPP earlier could help shorten the operation time.

Changes in Schlemm's canal, trabecular meshwork, and relevant parameters in the early stage after SMILE of myopia patients.

To observe the changes in Schlemm's canal (SC), trabecular meshwork (TM), and anterior chamber relevant parameters after small incision lenticule extraction (SMILE) of myopia patients. A total of 58 eyes from 30 patients who underwent SMILE were divided into a low and moderate myopia group (group A, 32 eyes) and a high myopia group (group B, 26 eyes). The diameter and area of the SC, the width and thickness of TM obtained by CIRRUS HD-OCT5000, and the related anterior chamber parameters obtained by Pentacam anterior segment analysis system, accommodation amplitude (AMP) were observed pre- and postoperatively. The preoperative intraocular pressure (IOP) and postoperative correction of intraocular pressure (IOPcc) were measured. The diameter and area of the SC in the two groups were significantly increased postoperatively (all P<0.01). The TM width of the patients in the two groups were increased at 1mo after surgery (both P<0.01), but the TM thickness did not change (P>0.05). The corneal curvature, central anterior chamber depth, and anterior chamber volume decreased after SMILE surgery (all P<0.01). There was a weak negative correlation between the SC area change and AMP change in group A (r=-0.362, P<0.01). The postoperative IOP decreased after correction by Shah formula (P<0.05). SC and TM in myopia patients change in the early postoperative stage of SMILE and the IOP is decline.

Vector analysis of moderate to high myopic astigmatism after small-incision lenticule extraction (SMILE): 12-month follow-up.

To evaluate the refractive outcomes of small-incision lenticule extraction (SMILE) surgery in moderate to high myopic astigmatism. Prospective interventional case series. This study evaluated 111 eyes of 68 patients treated with femtosecond SMILE surgery for the correction of myopia and astigmatism. Inclusion criteria were myopia of - 0.5 D or more and astigmatism between - 1.0 D and -5.0 D. Refractive and visual measurements were obtained preoperatively, 1 and 12 month(s) postoperatively. Vector analysis was used to study the astigmatic outcomes at 12-month follow-up. Comparison of results in two groups of patients with astigmatism below and over 3.00 D was performed. The preoperative mean spherical equivalent was -5.48 ± 2.17 D (range - 1.75 to - 10.00 D) and the mean cylinder was -2.02 ± 1.09 D (range - 1.00 to - 5.00 D). The mean postoperative cylinder value was -0.60 ± 0.52 D at 12-month visit. The 12-month safety and efficacy indices were 0.98 ± 0.07 and 0.97 ± 0.12, respectively. The high astigmatism group showed significantly lower safety and efficacy indices. The postoperative residual astigmatism was 0.5 D or less in 73% of the eyes. Higher amount of residual astigmatism was observed in the high astigmatism group. The angle of error was ± 5 degrees in 49% and ± 15 degrees in 87% of the eyes. SMILE surgery is effective and safe method for correcting myopic astigmatism. Vector analysis indicated a tendency for the under correction of astigmatism in subjects with high astigmatism.

A case of paracentral acute middle maculopathy after small incision lenticule extraction surgery.

A case of paracentral acute middle maculopathy after small incision lenticule extraction surgery.

Repeatability and reproducibility of corneal higher-order aberrations measurements after small incision lenticule extraction using the Scheimpflug-Placido topographer

BackgroundTo evaluate the precision of corneal higher-order aberrations measurements after small incision lenticule extraction (SMILE) using the Sirius Scheimpflug-Placido topographer (CSO, Italy).MethodsSeventy-five eyes from 75 postoperative subjects were included in this prospective study. Three consecutive corneal aberrometric measurements were obtained with the Scheimpflug-Placido topographer by two experienced operators to assess intra- and inter-observer reproducibility. The within-subject standard deviation (Sw), test-retest repeatability (TRT) and the intraclass correlation coefficient (ICC) were calculated.ResultsFor intraobserver repeatability of anterior and total corneal aberrations, all ICCs were more than 0.922, except for trefoil (0.722 to 0.768). The ICCs of total root mean square (RMS), coma Z (3, ± 1), and spherical aberration Z (4, 0) were over 0.810 while higher-order RMS, trefoil Z (3, ± 3), and astigmatism II Z (4, ± 2) were below 0.634 for posterior corneal surface aberrations. All Sw values for all types of aberrations were equal to or below 0.07 μm. Regarding interobserver reproducibility, all TRT values were no more than 0.12 μm, 0.05 μm, and 0.11 μm for anterior, posterior, and total corneal aberrations, respectively. The ICC values ranged from 0.875 to 0.989, from 0.686 to 0.976 and over 0.834 for anterior, posterior, and total corneal aberrations, respectively.ConclusionsThe repeatability of measurements of anterior and total corneal aberrations with the Sirius system in corneas after SMILE surgery was high, except for trefoil. There was some variability in posterior corneal aberrometric measurements. High reproducibility of corneal aberrometric measurements was observed between measurements of both examiners, except for trefoil, with poor to moderate reproducibility.

Double small incision lenticule extraction lenticular graft in impending corneal perforation

Purpose The aim of this study was to evaluate the safety and efficacy of double stromal lenticules, extracted by femtolaser small incision lenticule extraction (SMILE) surgery, as a surgical adjuvant for sealing of impending corneal perforation. Patients and methods The study included 20 eyes of 20 patients with impending corneal perforation. Double corneal stromal lenticules obtained through SMILE surgery, with a central thickness of 65 μm for each lenticule, were fixed over the corneal impending perforation site by 10-0 nylon interrupted stitches. The patients were monitored for a minimum of 6 months and were assessed using slit-lamp biomicroscopy, fluorescein stain, tonometry, and best spectacle-corrected visual acuity measurements. Postoperative complications were recorded throughout the follow-up period. Results The mean age of the patients was 51.25±1.49 years. The mean thickness of the used double SMILE lenticules was 108.85±10.77 μm (range, 90–120 μm). The preoperative best spectacle-corrected visual acuity was counting fingers at 30 cm in four patients, whereas the other 16 patients had a visual acuity of hand movement. Postoperatively, the corneal perforations were successfully sealed in 16 (80%) patients, and 15 (75%) patients exhibited a statistically significant improvement in visual acuity (P=0.02). During the follow-up period of 6 months, there was evidence of one case of infection and two cases of sliding graft. There was no significant association between the patients’ data and the reported complications except the association between complications and hand movement visual acuity. Conclusion The use of double corneal lenticules was a safe and effective surgical adjuvant for corneal perforation closure. It is a simple and inexpensive temporary measure to improve the corneal condition for further definitive interventions.