Longitudinal analysis of wound healing response post SMILE and LASIK surgery using proteomic profiling of tears.

Different types of refractive surgeries often exhibit differences in wound healing responses. The current study investigated post-operative tear protein profiles in subjects who underwent LASIK and SMILE to elucidate global changes to the proteomic profile during the period the patient cornea undergoes healing. In this study, 10 patients underwent LASIK and SMILE surgery with a contralateral paired eye design. Tear samples were collected using Schirmer's strips preoperatively, at 1 month, 3 months and 6 months postoperatively. Quantitative ITRAQ labeled proteomics was performed and the tear protein ratios were normalized to pre-operative protein levels for each subject. Whole proteomics identified 1345 proteins in tears from LASIK and 1584 proteins in SMILE across time points. About 67 proteins were common in LASIK and SMILE tears across all the time points. Wound healing responses were differentially regulated between two refractive surgeries (SMILE and LASIK). The proteins Ceruloplasmin, Clusterin, Serotransferrin were upregulated at 1 month and 3 months and downregulated at 6 months post operatively in LASIK surgery where as in SMILE these were downregulated. Galectin 3 binding protein showed upregulation at 1 month and the levels decreased at 3 months and 6 months postop in LASIK tears whereas the levels increased at 3 months and 6 months post-op in SMILE tears. The levels of proteins that protect from oxidative stress were higher in SMILE as compared to LASIK postoperatively. The extracellular matrix proteins showed an increase in expression at 6 months in SMILE tears and was stabilized at 6 months in LASIK tears post operatively. Different refractive surgeries induce distinct wound healing responses as identified in tears. This study has implications in targeting key proteins for improving the clinical outcome postrefractive surgery.

Femtosecond laser-assisted in situ keratomileusis versus small-incision lenticule extraction: current approach based on evidence.

PURPOSE OF REVIEW: Laser keratorefractive surgery achieves excellent visual outcomes for refractive error correction. With femtosecond laser, small incision lenticule extraction (SMILE) is an increasingly viable alternative to laser-assisted in situ keratomileusis (LASIK). Comparative studies demonstrate similar efficacy and predictability between SMILE and LASIK, making it difficult for clinicians to choose which to use. This review thus compares femtosecond-LASIK (FS-LASK) and SMILE in various scenarios, to assist clinicians in deciding which refractive surgery procedure to recommend. RECENT FINDINGS: SMILE may be superior for highly myopic eyes due to a smaller decrease in functional optical zone. SMILE further induces less spherical aberration and less overall higher order aberrations in mesopic conditions. SMIILE also has less postoperative dry eye, making it suitable those with preexisting dry eye. For low to moderate myopic astigmatism correction, FS-LASIK has less undercorrection compared to SMILE. Lastly, SMILE has not yet received Food and Drug Administration or Conformité Européenne approval for hyperopic correction, rendering FS-LASIK the choice of procedure for hyperopic correction. SUMMARY: Both FS-LASIK and SMILE demonstrate good efficacy and predictability. Understanding specific clinical scenarios where one may be superior to the other will aid clinicians in choosing the most suitable procedure for personalized care.

Characteristics of disk halo size and its correlation with lenticule quality in small incision lenticule extraction for moderate to high myopia.

PURPOSE: To investigate changes in disk halo size after small incision lenticule extraction (SMILE) and the correlation between halo size and lenticule quality in moderate to high myopia. METHODS: Thirty eyes of 30 consecutive patients (mean age, 24.9 ± 4.5 years; mean spherical equivalent, -6.85 ± 1.18 D) undergoing SMILE were included in this prospective study. Lenticule surface quality was accessed with a scanning electron microscopy by a scoring system. Halo size was measured preoperatively and at 1, 3, and 6 months postoperatively. Multiple linear regression analysis was performed to explore associations between halo size and a range of factors, including lenticule quality. RESULTS: Disk halo size increased slightly at 1 month and then recovered continually from 3 to 6 months postoperatively, with no difference between halo size during the preoperative period and at 6 months postoperatively (P > 0.05). One month after SMILE, halo size (1 cd/m2, 5 cd/m2) was associated only with uncorrected distance visual acuity (P ≤ 0.004). A halo size of 5 cd/m2 at 3 months postoperatively correlated with the anterior surface quality of the lenticule (P = 0.046). At 6 months postoperatively, a halo size of 1 cd/m2 was associated only with the baseline, accounting for 11.9% of the variability (P = 0.041); no correlations were found for the halo size of 5 cd/m2. CONCLUSIONS: Disk halo size after SMILE was enlarged at an early stage postoperatively and subsequently declined to the baseline level during a 6-month follow-up. The quality of the lenticule surface influenced halo size changes in the early phase.

Impact of the preoperative cylinder on astigmatism correction in femtosecond lenticule extraction (FLEX): a prospective observational study.

PURPOSE: To explore the impact of the preoperative manifest cylinder on astigmatism correction via femtosecond lenticule extraction (FLEX), or small incision lenticule extraction (SMILE). METHODS: This was a prospective observational study. Eyes were categorized into mild (n = 88), moderate (n = 46), and severe (n = 53) astigmatism groups, based on the preoperative manifest cylinder. Vector analysis was conducted with the back vertex distance set at 12 mm. The primary outcome was the correction index (CI), with secondary outcomes including the safety, efficacy, predictability, and vectoral alterations related to FLEX. RESULTS: The average target-induced astigmatism was 0.45 ± 0.20 D, 0.95 ± 0.17 D, and 1.99 ± 0.65 D in the three groups (P < 0.001), and the average CI was 1.12± 0.05, 1.01 ± 0.03, and 0.95 ± 0.02 (P = 0.020), with the severe astigmatism group displaying a notably lower CI. The efficacy, safety, predictability, or stability of FLEX did not demonstrate any significant differences among the three groups. The CIs exhibited a significant difference in eyes with with-the-rule (WTR) astigmatism and against-the-rule (ATR) astigmatism from the mild to severe astigmatism group. In eyes with oblique astigmatism, the average CI exceeded one. CONCLUSION: Patients with manifest cylinder exceeding 1.25 D have a heightened risk of under-correction in WTR and ATR astigmatism compared to those with mild astigmatism, and mild over-correction may occur in cases of oblique astigmatism.

Epithelial thickness remodeling after small incision lenticule intrastromal keratoplasty in correcting hyperopia measured by RTVue OCT.

PURPOSE: To characterize the in vivo corneal epithelial thickness (CET) remodeling profile in a population of eyes after small incision lenticule intrastromal keratoplasty (SMI-LIKE) for hyperopia. METHODS: The CET profile was measured by RTVue-100 Fourier-domain OCT system across the central 6-mm diameter of the cornea of 17 eyes from 12 subjects (five males and seven females) who accepted corneal stromal lens implantation surgery for correcting hyperopia. The CET were measured at positions with a radius of 0-1.0 mm, 1.0-2.5 mm (divided into eight quadrants) and 2.5-3.0 mm (divided into eight quadrants) from the corneal center. Corneal maximum simulated keratometry (Km) was measured by Pentacam HR anterior segment analyzer to analyze CET changes. The examination data of subjects were collected in four time periods, which were preoperative, short-term postoperative (one week after surgery), mid-term postoperative (the last review within 3-6 months after surgery), and long-term postoperative (the last review over 1-2.5 years after surgery). The changes of CET were compared and analyzed in the four time periods. RESULTS: Mean CET in 0-1.0 mm, 1.0-2.5 mm and 2.5-3.0 mm of the cornea decreased in one week after surgery, respectively, as compared to CET in the preoperative period, which turned from 55.06 ± 0.82 µm、54.42 ± 0.75 µm、53.46 ± 0.60 µm to 51.18 ± 1.05 µm (P = 0.005), 49.38 ± 0.70 µm (P = 0.000), 51.29 ± 0.59 µm (P = 0.025). In the mid-term postoperative period, mean CET in 0-1.0 mm and 1.0-2.5 mm areas kept thinner than mean CET in the preoperative period, CET in 0-1.0 mm is 50.59 ± 0.76 µm (P = 0.000),CET in 1.0-2.5 mm is 50.23 ± 0.57 µm (P = 0.000), while mean CET in 2.5-3.0 mm area recovered to the same thickness as the preoperative level, which is 54.36 ± 0.66 µm (P = 1.000), until the long-term period, CET stabilized in the above doughnut pattern. CONCLUSIONS: After stromal lenticule implantation for hyperopia, CET showed a remodeled form of thinning in the 0-2.5 mm area and thickening in the 2.5-3.0 mm area, and remained stable within one year after surgery.

Comparative visual outcomes of the first versus second eye following small-incision lenticule extraction (SMILE).

BACKGROUND: This study aimed to compare the visual outcomes of the first operated eyes with those of the second operated eyes following small-incision lenticule extraction (SMILE). METHODS: A total of 202 patients (404 eyes) underwent SMILE using the tear film mark centration method for myopia and myopic astigmatism correction. Baseline characteristics, objective optical quality, decentered displacement, induced corneal aberrations, and modulation transfer function (MTF) values were assessed. Linear regression analyzed the relationship between decentration and visual quality parameters, including corneal aberrations and MTF values. RESULTS: No significant difference was observed in objective visual quality, efficacy, and safety indexes between the two groups (all P > 0.05). The average decentered displacement for the first and second surgical eyes was 0.278 ± 0.17 mm and 0.315 ± 0.15 mm, respectively (P = 0.002). The horizontal coma in the first surgical eyes were notably lower than in the second (P = 0.000). MTF values at spatial frequencies of 5, 10, 15, and 20 cycles/degree (c/d) were higher in the first surgical eyes compared to the second (all P < 0.05). Linear regression indicated that high-order aberrations (HOAs), root mean square (RMS) coma, spherical aberration, horizontal coma, vertical coma, and eccentric displacement were all linearly correlated. Furthermore, MTF values exhibited a linear relationship with eccentric displacement across these spatial frequencies. CONCLUSIONS: There was no discernible difference in visual acuity, efficacy, or safety between the two operated eyes. Nonetheless, the first operated eyes exhibited reduced decentered displacement and demonstrated superior outcomes in terms of horizontal coma and MTF values compared to the second operated eyes following SMILE. The variations in visual quality parameters were linearly correlated with decentered displacement.

A new technique to implant intracorneal ring-segments from the perilimbal region: one-year prospective pilot study report.

BACKGROUND: Recently a new surgical technique for intracorneal ring-segments (ICRS) assisted by femtosecond laser (FSL) called ByLimB was developed, involving the creation of the incision from a paralimbic region. This study aims to evaluate the safety and efficacy of the ByLimb technique following one year of follow-up. METHODS: A prospective, single-center study was conducted at the Zaldivar Institute in Buenos Aires, Argentina. Keratoconus patients with indication for ICRS-FSL assisted procedure, operated with the ByLimb technique were included. By using the ByLimb technique, the ICRS are placed without affecting the tunnel's roof, and the end of the ICRS is always away from the incision area. Visual acuity, topographic astigmatism, and the occurrence of complications were evaluated. Safety index was the main outcome and efficacy indes was a complimentary outcome. RESULTS: A total of 17 eyes completed the 12-month follow-up period. The safety index was 1.10 (mean postoperative corrected distance visual acuity (CDVA) in decimal: 0.76/preoperative CDVA: 0.69), while the efficacy index was 0.89 (mean postoperative uncorrected distance visual acuity UDVA in decimal: 0.62/preoperative CDVA: 0.69). Mean preoperative astigmatism was 5.3 ± 2.3, decreasing twelve months after surgery at 2.1 ± 1.2 (p < 0.001). No eye loss lines of vision and no intraoperative complications were observed. During the first month after surgery, an improper positioning of the ICRS based on topographic assessment was detected in five cases. A second procedure was performed, which consisted of opening the incision and introducing a Sinsky hook, through which the ICRS was mobilized and placed in its correct position. No incisional alterations, signs of infection, anterior segment anomalies, or fundus alterations were observed. CONCLUSION: FSL-assisted ICRS implantation through the perilimbal region has demonstrated an adequate safety index one year post-surgery. Additionally, this technique has facilitated accurate realignment of ICRS during secondary surgical interventions within one-month post-surgery. While the current findings are promising, continued follow-up of these cases is warranted.

Comprehensive assessment of corneal microstructural changes following V4c implantable collamer lens surgery using in vivo confocal microscopy.

BACKGROUND: Implantable Collamer Lense (ICL) presents a viable alternative to conventional refractive surgeries, but their impact on corneal microstructure remains unclear. By employing in vivo confocal microscopy (IVCM), we examined changes in stromal and endothelial cells following the insertion of V4c ICLs, with the goal of enhancing post-surgical care and outcomes. METHODS: In this longitudinal investigation, we conducted detailed preoperative assessments on 103 eyes from 53 participants. Follow-up evaluations were carried out after surgery at set intervals: one day, one week, one month, three months, six months, and twelve months. We used IVCM to analyze changes in stromal and endothelial cells. To assess differences between pre- and post-surgery variables and to investigate correlations with age, axial length (AL), and spherical equivalent refraction (SER), we applied a repeated measures mixed-effects model, with statistical significance set at P < 0.05. RESULTS: No vision-threatening complications were reported post-surgery. Significant reductions in stromal cell density (SCD) were observed postoperatively, with anterior and mid- SCD reaching their lowest values at 3 months and posterior SCD at 1 month, remaining below baseline at 12 months. endothelial cell density (ECD) and percentage of hexagonal cells (PHC) decreased initially, recovering by 12 months. Conversely, endothelial cellular area (ECA) and coefficient of variation of cell size (CoV) increased postoperatively, with the most significant change at 1 week. Endothelial deposits were detected in 49 of 101 eyes on postoperative day 1, half of them were absorbed within 3 months post-surgery. Changes in posterior SCD were negatively related to AL, while AL, SER, lens thickness showed associated with endothelium changes. CONCLUSION: Our findings elucidate the corneal microstructural changes following V4c ICL implantation, particularly the significant early reductions in stromal and endothelial cell densities. We recommend careful management of viscoelastics during surgery to minimize endothelial deposits that may harm the endothelium. Enhanced early postoperative monitoring and these surgical adjustments can lead to improved surgical and post-surgical care, ultimately supporting better patient recovery.

Topographic and surgical risk factors for high postoperative residual astigmatism after small incision lenticule extraction in patients with different degrees of myopia: a retrospective cohort study.

BACKGROUND: To evaluate the possible topographic and surgical risk factors for high postoperative residual astigmatism in patients who undergo small-incision lenticule extraction (SMILE) surgery and have different myopia degrees. METHODS: A retrospective cohort study was conducted, and patients who underwent SMILE surgery were enrolled. A total of 80 and 150 eyes from 40 to 75 individuals, respectively, were selected as the low myopia and high myopia groups. The demographic data, visual acuity, refraction, topographic parameters and surgical settings were recorded. Multiple linear regression with interaction tests were performed to survey the risk factors for high postoperative residual astigmatism in each group. RESULTS: Five (6.25%) and 9 (6.00%) eyes presented with high postoperative residual astigmatism in the low myopia and high myopia groups, respectively, but these differences were not significant (P = 0.569). A steep corneal curvature was correlated with a greater risk of high postoperative residual astigmatism in the low myopia group (P = 0.015), while a higher degree of cycloplegic cylinder power, steeper corneal curvature, greater topographic cylinder power, smaller optic zone and longer incision length were associated with a high rate of postoperative residual astigmatism in the high myopia group (all P < 0.05). In addition, the interaction effects of cycloplegic and topographic cylinder power and longer incision length on the incidence of high postoperative residual astigmatism development were more evident in the high myopia group than in the low myopia group (all P < 0.05). CONCLUSIONS: A steep corneal curvature correlates with a high risk of high postoperative residual astigmatism after SMILE surgery, and a higher degree of cycloplegic and topographic cylinder and longer incision are associated with high postoperative residual astigmatism in individuals with high myopia.

Association of myopia and astigmatism with postoperative ocular high order aberration after small incision lenticule extraction.

OBJECTIVE: To investigate the correlation between higher-order aberrations (HOA) after small incision lenticule extraction (SMILE) and the severity of myopia and astigmatism, along with the relevant factors. These findings will provide valuable insights for decreasing the occurrence of HOA after SMILE and enhancing visual quality. METHODS: A total of 75 patients (150 eyes) with myopia and astigmatism who underwent SMILE were categorized into four groups based on the severity of myopia and astigmatism: Myopia Group 1 (Group M1, spherical diopter ranged from -1.00 D to -4.00 D), Myopia Group 2 (Group M2, spherical diopter ranged from -4.10 D to -10.00 D), Astigmatism Group 1 (Group A1, cylindrical diopter ranged from 0 D to -1.00 D), and Astigmatism Group 2 (Group A2, cylindrical diopter ranged from -1.10 D to -3.00 D). A comprehensive assessment was performed to examine the association between HOA and various relevant factors, including a detailed analysis of the subgroups. RESULTS: Group M1 had significantly lower levels of total eye coma aberration (CA), corneal total HOA (tHOA), internal tHOA, and vertical CA ( Z 3 - 1 ) after SMILE than Group M2 (P < 0.05). Similarly, Group A1 had significantly lower levels of total eye tHOA, CA, trefoil aberration (TA), corneal tHOA, TA, and vertical TA ( Z 3 - 3 ) after SMILE than Group A2 (P < 0.05). Pearson correlation analysis indicated a statistically significant positive relationship between the severity of myopia/astigmatism and most HOA (P < 0.05). Subgroup evaluations demonstrated a notable increase in postoperative HOA associated with myopia and astigmatism in Groups M2 and A2 compared with the control group. Lenticule thickness, postoperative central corneal thickness (CCT), postoperative uncorrected distance visual acuity (UDVA), and postoperative corneal Km and Cyl were strongly correlated with most HOA. Age, eyes, and postoperative intraocular pressure (IOP) were only associated with specific HOA. CONCLUSION: HOA positively correlated with the severity of myopia and astigmatism after SMILE. However, this relationship was not linear. HOA after SMILE was influenced by various factors, and additional specialized investigations are required to establish its clinical importance.

Corneal stromal lenticule transplantation for the treatment of congenital optic disc pit maculopathy : a case report and review.

BACKGROUND: Congenital optic disc pit (ODP) is a relatively uncommon congenital anomaly of the optic disc, which seriously affects the patient's vision when combined with optic disc pit maculopathy(ODP-M). Currently, the treatment of ODP-M remains a clinical challenge and a focus of research. CASE PRESENTATION: A boy had a pit in the inferotemporal segment of the optic disc with ODP-M. Optical Coherence Tomography(OCT) showed ODP and serous retinal detachment. He was treated with pars plana vitrectomy(PPV), followed by Corneal Stromal Lenticule (CSL) sealing and C3F8 tamponade. In the end, significant anatomical improvement was achieved, and the Best Corrected Visual Acuity(BCVA) was improved. CONCLUSIONS: The CSL transplantation may be a viable therapeutic option for improving ODP-M with stable anatomical and functional result. However, more cases and longer follow-up are needed to confirm the safety and effectiveness of the technology.

Interface fluid syndrome caused by the corneal perforation injury after small incision lenticule extraction: a case report.

BACKGROUND: To report a case of interface fluid syndrome (IFS) following traumatic corneal perforation repair after small incision lenticule extraction (SMILE). CASE PRESENTATION: A 23-year-old woman, with a past history of SMILE, was struck in the left eye with a barbecue prod and subsequently underwent corneal perforation repair at local hospital. Primary wound repaired with a single 10 - 0 nylon suture at the area of leakage. After the surgery, her best corrected visual acuity (BCVA) was 20/30. Four days later, she presented at our hospital with blurred vision, and interface fluid syndrome (IFS) was diagnosed. Intraoperative optical coherence tomography (iOCT) was used to guide the resuturing of the corneal perforation in the left eye, followed by anterior chamber gas injection. At the first postoperative month, the BCVA was 20/25. The corneal cap adhered closely to the stroma, the surface became smooth. CONCLUSIONS: This case illustrates that any corneal perforation following lamellar surgery, including SMILE, may lead to IFS. It is crucial to consider the depth of corneal perforation, and intraoperative optical coherence tomography (iOCT) plays a unique role in the repair procedure.

Study of corneal and retinal thicknesses at five years after FS-LASIK and SMILE for myopia.

BACKGROUND: This study aimed to observe corneal and retinal thicknesses at 5 years after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) for myopia, investigate the effect of epithelial remodeling on refractive status and visual quality, and compare retinal thicknesses among fundus tessellation grades. METHODS: Patients who received FS-LASIK or SMILE 5 years before were enrolled in this cross-sectional study. After 1:1 propensity score matching, each surgical group obtained 177 patients (177 eyes). Examinations including visual acuity, refraction, corneal and retinal thicknesses, corneal higher-order aberrations (HOAs), and fundus photography were performed in this visit at 5 years after surgery. The Quality of Vision (QoV) questionnaire was used to assess visual symptoms and overall satisfaction. Corneal and retinal thicknesses between groups were compared, contributing factors were analyzed, and correlations with postoperative refractive status, HOAs, QoV scores and overall satisfaction were evaluated. RESULTS: The discrepancy of epithelial thickness between central and pericentral zones in FS-LASIK group was larger than that in SMILE group, which was negatively correlated with postoperative spherical equivalent (SE), positively correlated with spherical aberration (all P < 0.05), but not correlated with QoV scores and overall satisfaction (all P > 0.05) in both surgical groups. There was no statistical difference in stromal thickness and total corneal thickness (all P > 0.05). Most annuluses of epithelial and stromal thicknesse were linearly related to preoperative SE (all P < 0.05). The macular thickness, ganglion cell complex thickness, and retinal nerve fiber layer thickness exhibited comparable values between two surgical groups and four fundus tessellation grades, with no significant association observed with postoperative SE (all P > 0.05). CONCLUSION: The tendency that epithelial thickness in central zone was thicker than peripheral zone was more obvious at 5 years after FS-LASIK compared to SMILE. This uneven distribution of epithelial thickness might play a role in myopic regression and the changes in HOAs, especially in patients with high myopia, but it had little effect on patients' subjective visual quality and satisfaction. Retinal thicknesses were not affected by these two surgical methods, and they did not appear to be the clinical indicators for myopic regression or fundus tessellation progression.

Comparison of long-term changes in the effective optical zone following SMILE and FS-LASIK for moderate and high myopia.

BACKGROUND: Visual quality after corneal refractive surgery is linked to the postoperative effective optical zone (EOZ). This study aims to compare long-term changes in the EOZ following small incision lenticule extraction (SMILE) and femtosecond laser-assisted in-situ keratomileusis (FS-LASIK) for moderate and high myopia. METHODS: This study included 42 patients (72 eyes) who underwent either SMILE (36 eyes) or FS-LASIK (36 eyes). A custom software program based on the tangential curvature difference map of the Pentacam HR (Oculus Optikgeräte GmbH) was used to define the EOZ at 3 and 7 years postoperatively. The EOZ, its chronological changes compared to the programmed optical zone (POZ), and the corneal wavefront aberrations following SMILE and FS-LASIK were analyzed. Correlations between the EOZ changes and relevant parameters were evaluated. RESULTS: Three years postoperatively, EOZ following SMILE and FS-LASIK were 5.13 ± 0.27 mm and 4.70 ± 0.24 mm (P < 0.001), respectively. Seven years postoperatively, EOZ following SMILE and FS-LASIK decreased to 5.03 ± 0.28 mm and 4.63 ± 0.23 mm (P < 0.001), respectively. At postoperative 7 years, the percentages of EOZ/POZ were negatively correlated with Q-value changes (ß = -5.120, P = 0.009) following SMILE and positively correlated with the cylinder correction (ß = 1.184, P = 0.004) following FS-LASIK. The induced spherical aberrations in the SMILE group were less than those in the FS-LASIK group (P < 0.05) and were negatively correlated with the EOZ/POZ (ß = -16.653, P < 0.001). CONCLUSIONS: The EOZ following SMILE was larger than that following FS-LASIK in the long postoperative term for moderate and high myopia. Furthermore, a continual reduction in the EOZ was noted after both surgical modalities.

Clinical outcomes of femtosecond laser-assisted corneal allogenic intrastromal ring segment (CAIRS) in the treatment of keratoconus.

BACKGROUND: To evaluate the results of corneal allogenic intrastromal ring segment (CAIRS) implantation in keratoconus. METHODS: The medical records of patients with keratoconus who underwent CAIRS implantation were reviewed. The CAIRS, prepared by trephination from the donor cornea, was implanted into a tunnel created using the femtosecond laser. The depth of the tunnel was 200 µ; the inner diameter of the tunnel was 4.5 mm; and the outer diameter was 7 mm. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), keratometry, minimum corneal thickness (CT), endothelial cell density (ECD), and high order aberration values were recorded preoperatively and at the 1st, 3rd, and 6th months postoperatively. RESULTS: A total of 23 eyes of 23 patients were included in the study. Preoperative UCVA (0.08 ± 0.01) and BCVA (0.25 ± 0. 11) values improved postoperatively and reached 0.40 ± 0.05 and 0.68 ± 0.09, respectively, at the end of the 6-month follow-up period (p1 < 0.001, p2 = 0.016; respectively). A statistically significant flattening of all keratometric values was observed in the postoperative period compared to preoperatively (p < 0.001 for all). There were no statistical differences between CT and ECC values at the preoperative and postoperative visits (p1 = 0.654, p2 = 0.769; respectively). In addition, coma aberration values were lower than the preoperative values at all postoperative visits (p < 0.05 for all). CONCLUSIONS: These results suggest that CAIRS implantation is a safe treatment option with good visual and keratometric outcomes for suitable patients with keratoconus.

Simultaneous Deep Anterior Lamellar Keratoplasty and Descemet Membrane Endothelial Keratoplasty for Corneal Endothelial Failure With Stromal Scarring.

ABSTRACT: We present an alternative surgical procedure including simultaneous deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK) in a case with endothelial failure and stromal scarring. A 62-year-old woman presented with vision loss caused by pseudophakic bullous keratopathy. While waiting for a corneal transplant, the patient developed infectious keratitis, which was treated with medication. Although the keratitis healed, it left a scar. To improve the patient's vision, a corneal transplant surgery that included simultaneous DALK and DMEK was performed. Postoperatively, the corneal graft was clear, and the Descemet membrane was well attached. However, there was an interface haze because of residual stromal tissue. The patient's best-corrected visual acuity improved from hand motion to 0.2 (decimal). This combined procedure allows for lamellar keratoplasty in cases with coexistence of corneal endothelial and stromal involvement.

Intrastromal corneal ring segments for keratoconus patients: up to 12 years follow up.

PURPOSE: Intrastromal corneal ring segment (ICRS) implantation is a surgical technique developed with the purpose of avoiding the progression of corneal protrusion and is considered a viable option for managing patients with keratoconus as it stabilizes or improves vision thus delaying or excluding the need of more advanced surgical intervention such as penetrating keratoplasty. However, long term follow up is still limited to determine its actual success in achieving this goal. The current project aims to provide an extended follow up reporting a mean followup of around 5 years, extending up to 12.5 years. METHODS: We recruited patients who performed their ICRS between 2008 and 2013. We contacted patients for a follow up exam with a possible corneal tomography. For each patient, we obtained baseline pre operative data and latest follow up data which included visual acuity, subjective refraction, clinical slit-lamp exam, and corneal tomography. We compared the change in best corrected visual acuity and maximum keratometry readings from clinical visits before ring implantation to the latest follow up. RESULTS: A total of 68 eyes for 53 patients were included. The mean duration of follow up was 53.87 (± 38.8) months, with a maximum duration of 153 months. We found a significant improvement in corrected and uncorrected visual acuity, keratometries and refraction during the follow up period. On correlation analysis, strong negative significant correlation was found between duration since surgery and change in uncorrected visual acuity (p = 0.03, ρ = 0.338) and mean keratometry values (p = 0.033, ρ = 0.296). At the latest follow up for majority of patients with more than 100 weeks of follow up (12 eyes), uncorrected visual acuity were equal to or worse than baseline. CONCLUSION: This study represents the largest follow up for ICRS implanted in keratoconus patients. Improvement of visual acuity following ICRS implantation can be expected in the first few years, after which, a decline occurring thereafter.

Banking of post-SMILE stromal lenticules for additive keratoplasty: A new challenge for eye banks?

PURPOSE: ReLEx (Refractive Lenticule Extraction) Small Incision Lenticule Extraction (SMILE), the second generation of ReLEx Femtosecond Lenticule Extraction (FLEx), is a minimally invasive, flapless procedure designed to treat refractive errors such as myopia, hyperopia, presbyopia, and astigmatism. This review aims to provide a comprehensive overview of the methods for preserving SMILE-derived lenticules and discusses their potential future applications. METHODS: A narrative literature review was conducted using PubMed, Scopus, and Web of Science databases, focusing on articles published up to January 2024 and available in English. The authors also evaluated the reference lists of the collected papers to identify any additional relevant research. RESULTS: No standardized protocols currently exist for the storage or clinical application of SMILE-derived lenticules. However, these lenticules present a promising resource for therapeutic uses, particularly in addressing the shortage of donor corneal tissues. Their potential applications include inlay and overlay additive keratoplasty, as well as other ocular surface applications. Further research is needed to establish reliable protocols for their preservation and clinical use. CONCLUSION: SMILE-derived lenticules offer significant potential as an alternative to donor corneal tissues. Standardizing their storage and application methods could enhance their use in clinical settings.

Refractive outcomes of small lenticule extraction (SMILE) Pro® with a 2 MHz femtosecond laser.

PURPOSE: To evaluate the initial visual outcomes of Small Incision Lenticule Extraction (SMILE) Pro® using a 2 MHz femtosecond laser (VisuMax 800, Carl Zeiss Meditec) and to assess the efficacy, safety, predictability, accuracy, and complication rate. METHODS: This retrospective analysis included eyes which underwent the SMILE Pro® procedure using VisuMax 800 femtosecond laser to correct myopia. All surgeries were performed by one surgeon (DB). Follow-up was conducted 3 months postoperatively to evaluate visual outcomes after neuroadaptation, corrected visual acuity (CDVA) and intra- and postoperative complications. RESULTS: One hundred and fifty-two eyes of 82 patients (mean age 31 ± 6 years) results at 3 months are presented. The mean spherical equivalent (SE) was - 4.44 ± 1.86 D preoperatively while -0.24 ± 0.32 D postoperatively. 99% of eyes achieved SE within ± 1.0 D of attempted correction and 91% were within ± 0.5 D. Efficacy index was 0.93 while the safety index was 1. No complications occurred intra- or postoperatively. No eyes lost more than 1 line of their preoperative CDVA. All highly myopic eyes (- 6.25 to - 10.00 D; n = 18) achieved 20/20 at 3 months postoperatively and were within 0.5 D from the attempted SE and no eyes lost more than 1 line of CDVA. CONCLUSION: The SMILE Pro® is a safe, efficient, and predictable procedure for the treatment of myopia and myopic astigmatism, with comparable results of conventional SMILE surgery. High myopic eyes achieve better results than low and moderate myopia. No complications were recorded in our patients.

Biochemical component analysis of human myopic corneal stroma using the Raman spectrum.

PURPOSE: This study aimed to measure the Raman spectrum of the human corneal stroma lens obtained from small incision lenticule extraction surgery (SMILE) in Asian myopic eyes using a confocal Raman micro-spectrometer built in the laboratory. METHODS: Forty-three myopic patients who underwent SMILE with equivalent diopters between - 4.00 and - 6.00 D were selected, and the right eye data were collected. Corneal stroma lenses were obtained during surgery, and the Raman spectra were measured after air drying. The complete Raman spectrum of human myopic corneal stroma lens tissue was obtained within the range of 700-4000 cm-1. RESULTS: Thirteen characteristic peaks were found, with the stronger peaks appearing at 937 cm-1, corresponding to proline, valine, and the protein skeleton of the human myopic corneal stroma lens; 1243 cm-1, corresponding to collagen protein; 1448 cm-1, corresponding to the collagen protein and phospholipids; and 2940 cm-1, corresponding to the amino acid and lipids, which was the strongest Raman peak. CONCLUSION: These results demonstrated that Raman spectroscopy has much potential as a fast, cost-effective, and reliable diagnostic tool in the diagnosis and treatment of eye diseases, including myopia, keratoconus, and corneal infection.