Comparison of Complication Rates between Manual and Femtosecond Laser-Assisted Techniques for Intrastromal Corneal Ring Segments Implantation in Keratoconus

Monteiro, Tiago; Alfonso, José F.; Freitas, Rui; Franqueira, Nuno; Faria-Correira, Fernando; Ambrósio, Renato; Madrid-Costa, David

doi:10.1080/02713683.2019.1635165

Cited by 26 publications

(32 citation statements)

References 31 publications

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“…It seems to be more critical for better visual and refractive outcomes to implement a correct classification of the ectasia and a personalized nomogram of implantation, rather than the surgical procedure itself. However, beyond visual and refractive outcomes, it should be noted the manual mechanical technique had a higher rate of complications than the femtosecond technique, demonstrating, as previously reported, 13 that the femtosecond laser–assisted surgery is a safer procedure.…”

Section: Discussionmentioning

confidence: 57%

“…Studies have shown that manual channel creation for ICRS implantation has been associated with various potential complications, including infectious keratitis, epithelial defects, anterior or posterior corneal perforations, corneal stromal oedema around the incision, extension of the incision towards the central visual axis or the limbus and asymmetric segment placement. 13–17 We have previously reported that ICRS implantation with femtosecond laser–assisted surgery is a more precise technique, achieving a more accurate implantation depth, with no difference between the intended and the achieved depth of implantation, when compared to a manual mechanical procedure. 7 Safety parameters are the main difference observed between techniques in our study.…”

Section: Discussionmentioning

confidence: 99%

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Comparison of clinical outcomes between manual and femtosecond laser techniques for intrastromal corneal ring segment implantation

Monteiro

Alfonso

Franqueira

et al. 2019

European Journal of Ophthalmology

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Purpose: The purpose was to compare the visual, refractive and aberrometric results of intrastromal corneal ring segments implantation with manual dissection and femtosecond laser–assisted surgery. Methods: This is a multicentre study, which included consecutive patients with paracentral keratoconus, in which the difference between the axes of the topographic flattest and the coma aberration was <60°, who had Ferrara-type intrastromal corneal ring segment implantation using manual dissection or femtosecond laser technique. LogMAR uncorrected (uncorrected distance visual acuity) and corrected (corrected distance visual acuity) distance visual acuity, refractive errors and the root mean square for corneal coma-like aberration were recorded before and at 6 months after surgery. Results: The study included 84 and 110 eyes in the manual group and in the femtosecond group, respectively. After surgery, there was a statistically significant improvement in uncorrected distance visual acuity and corrected distance visual acuity for both groups ( p < 0.0001), and there were no statistically significant differences between groups ( p > 0.3). For both groups, there was a reduction in spherical equivalent after intrastromal corneal ring segment implantation ( p < 0.0001). There were no statistically significant differences between groups in the magnitude of spherical equivalent reduction ( p = 0.34) The magnitude of the root mean square coma-like reduction was 0.93 ± 0.76 and 0.83 ± 0.80 μm in the manual and femtosecond group, respectively ( p = 0.2). While in the femtosecond laser group no complications were reported, in the manual group, the intraoperative or postoperative complications rate was 13.09%. Conclusion: Although both surgical techniques provide comparable visual, refractive and aberrometric outcomes, it should be noted that the femtosecond laser is a safer surgical procedure, with no complications reported.

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Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Comparison of clinical outcomes between manual and femtosecond laser techniques for intrastromal corneal ring segment implantation

Monteiro

Alfonso

Franqueira

et al. 2019

European Journal of Ophthalmology

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“…Also, in a study by Monteiro et al [17], they compared the incidence of complications between manual and femtosecond laser-assisted surgery for ICRS implantation and found that there were complications in 18.11% of eyes of the manual group while in the femtosecond laser only 3.6% of eyes. In the manual group, ICRS spontaneous extrusion occurred in 5.66%.…”

Section: Discussionmentioning

confidence: 99%

Extrusion of Femtosecond Laser-Implanted Intrastromal Corneal Ring Segments in Keratoconic Eyes: Prevalence, Risk Factors, and Clinical Outcomes

Mounir

Farouk

Abdellah

et al. 2020

Journal of Ophthalmology

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Purpose. To evaluate the prevalence, possible risk factors, and clinical results of femtosecond laser implanted intrastromal corneal ring segment (ICRS) extrusion in keratoconic eyes. Patients and Methods. This is a retrospective observational study evaluating 333 eyes of 269 patients who were subjected to femtosecond laser-implanted Keraring ICRS in the Sohag Refractive Center, Sohag, Egypt, from January 2014 to January 2019. The study included eyes with channels created by a femtosecond laser (60 kHz IntraLase femtosecond system; Advanced Medical Optics, Santa Ana, California, USA) with implantation of Keraring intrastromal corneal ring segments (Mediphacos, Belo Horizonte, Brazil). Patient data and causes of Keraring extrusions were identified as being those rings that migrated or showed melting of the cornea with no other reason which required segment removal. Results. Seven eyes were found to fit the criteria of ring extrusion (2.1%) out of the 333 eyes which had Keraring implantation. All extruded rings were from patients with keratoconus grade 3, with eccentric cones, and with femtosecond creation of the tunnel. Four eyes belonging to 3 patients (57.1%) had a history of vernal Keratoconjunctivitis, yet they did not show signs of activity at the time of implantation. They reported excessive rubbing just before they presented with conjunctival hyperemia and foreign body sensation. Five eyes (71.4%) showed chronic sun exposure. The mean minimal corneal thickness was 401.85 μm (range 384–420 μm), while the mean maximum keratometry was 61 D (range 55.18–68.96 D). Most of the extruded rings had large arcs. Six eyes had crosslinking (CXL) at the same session of the Keraring implantation. The simultaneous CXL treatment is considered as a possible significant risk factor for ring extrusion. Conclusion. ICRS is an effective reversible option for patients with keratoconus who are intolerant to hard contact lenses, yet the choice of cases and ring segments is mandatory for satisfactory results. Moreover, meticulous history taking and examination reduces the incidence of complications including extrusion.

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“…They found that careful evaluation and timing of the CXL can be considered as preoperative options to achieve satisfactory results. In an earlier study 33 , they reported the incidence of complications for manual interstation at , with spontaneous extrusion of the ICRS occurring at , while with the femtosecond laser only of the eyes affected by implant extrusion occurred. Accordingly, these observations clinically support the biomechanically assessed influences of corneal stiffness and implementation technique on corneal instability and implant extrusion.…”

Section: Discussionmentioning

confidence: 99%

Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

Bagheri

Kadkhodaei

Pirhadi

et al. 2021

Sci Rep

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The implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value ($$\text {K}_{\text{mean}}$$ K mean ) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower $$\text {K}_{\text{mean}}$$ K mean value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient’s keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.

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Comparison of Complication Rates between Manual and Femtosecond Laser-Assisted Techniques for Intrastromal Corneal Ring Segments Implantation in Keratoconus

Cited by 26 publications

References 31 publications

Comparison of clinical outcomes between manual and femtosecond laser techniques for intrastromal corneal ring segment implantation

Comparison of clinical outcomes between manual and femtosecond laser techniques for intrastromal corneal ring segment implantation

Extrusion of Femtosecond Laser-Implanted Intrastromal Corneal Ring Segments in Keratoconic Eyes: Prevalence, Risk Factors, and Clinical Outcomes

Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

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