Results of intrastromal corneal ring segment implanted alone or combined with same-day corneal crosslinking and their correlation with preoperative corneal biomechanical strain from finite element analysis

Serpe, Crislaine Caroline; Mello, Glauco Reggiani; Seven, Ibrahim; Dupps, William J.; Santhiago, Marcony R.

doi:10.1097/j.jcrs.0000000000000533

Cited by 5 publications

(3 citation statements)

References 20 publications

(37 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This led to an asymmetric decrease in topographic parameters, resulting in a significant decrease in SIF or SIB ( Supplementary Table S1 ). Moreover, recent studies have reported an association between the loss of Snellen lines for CDVA and an increase in the I-S difference [ 28 , 29 ]. In typical keratoconus, coma aberration appears with a delayed wavefront in the inferior cornea and an advanced wavefront in the superior cornea, consistent with a vertical asymmetric corneal shape [ 30 ].…”

Section: Discussionmentioning

confidence: 99%

Asymmetric Intrastromal Corneal Ring Segments with Progressive Base Width and Thickness for Keratoconus: Evaluation of Efficacy and Analysis of Epithelial Remodeling

Benlarbi

Kallel

David

et al. 2023

JCM

View full text Add to dashboard Cite

Purpose: The aim of this study is to describe visual outcomes and epithelial remodeling following the implantation of asymmetric intracorneal ring segments (ICRSs) of variable thickness and base width for the management of duck-type keratoconus. Methods: A prospective observational study of patients with duck-type keratoconus was conducted. All patients received one ICRS AJL PRO + implant (AJL Ophthalmic). We analyzed demographic and clinical data, anterior segment optical coherence tomography (AS-OCT) data and Scheimpflug camera images obtained with a Placido disc MS-39 (CSO, Firenze, Italy) one and six months after surgery to determine keratometric and aberrometric outcomes and epithelial remodeling. Results: We studied 33 keratoconic eyes. ICRS implantation significantly improved both corrected distance visual acuity (CDVA) and uncorrected distance visual acuity at six months, as assessed with the logMAR (minimum angle of resolution) system, from 0.32 ± 0.19 to 0.12 ± 0.12 (p < 0.001) and from 0.75 ± 0.38 to 0.37 ± 0.24 (p < 0.001), respectively. Overall, 87% of implanted eyes gained ≥ 1 line of CDVA, and 3% of patients (n = 1) lost one line of CDVA; 55% of eyes attained a manifest refraction spherical equivalent between +1.50 and −1.50 D. Epithelial remodeling was greater at the wider and thicker end (+11.33 µm ± 12.95; p < 0.001 relative to the initial value) than at the narrower and thinner end (+2.24 µm ± 5.67; p = 0.01). Coma aberration was significantly reduced from 1.62 ± 0.81 µm to 0.99 ± 0.59 µm (p < 0.001). Conclusions: AJL-PRO + ICRS implantation for duck-type keratoconus improves refractive, topographic, aberrometric and visual parameters and induces progressive epithelial thickening along the segment.

show abstract

Section: Discussionmentioning

confidence: 99%

Asymmetric Intrastromal Corneal Ring Segments with Progressive Base Width and Thickness for Keratoconus: Evaluation of Efficacy and Analysis of Epithelial Remodeling

Benlarbi

Kallel

David

et al. 2023

JCM

View full text Add to dashboard Cite

show abstract

“…This strengthening effect varies with the type, number, thickness, and arc length of segment(s) and could explain the variability of the biomechanical results. 27 Nevertheless, tissue alterations occurring in response to ICRS implantation such as perisegmental fibrosis, 28 especially in extreme cases, 29 or a combination of ICRS implantation with CXL, 30 could also directly alter the corneal biomechanics. As air-puff corneal deformation has been proven to inherently depend on additional factors such as IOP and corneal geometry, 31 biomechanical analysis using pneumotonometers may be biased by ICRS-induced geometrical changes, leaving the measurements uninterpretable or being misinterpreted.…”

Section: Discussionmentioning

confidence: 99%

Implantation of Intracorneal Ring Segments in Keratectasia: Effects on Corneal Biomechanics in 112 Eyes

Hamon,

Pfahl,

Flockerzi

et al. 2023

Cornea

View full text Add to dashboard Cite

Purpose: The aim of this study was to analyze changes in corneal biomechanical properties after implantation of intracorneal ring segments (ICRSs) in keratectasia. Methods: This retrospective single-center study included 112 patient eyes that underwent femtosecond laser-assisted ICRS implantation (Intacs SK; Addition Technology Inc, Des Plaines, IL) for keratectasia. Biomechanical analysis was performed using the Ocular Response Analyzer (ORA; Reichert Inc, Depew, NY), with determination of corneal resistance factor, corneal hysteresis, and Keratoconus Match Index, as well as by Corvis ST (OCULUS, Wetzlar, Germany), with determination of stiffness parameter A1, Ambrosio relational thickness to the horizontal profile (Arth), integrated radius, deformation amplitude ratio, and stress–strain index as well as Corvis Biomechanical Index and Tomographic Biomechanical Index. Data collection was performed preoperatively and 6 months postoperatively for ORA and Corvis ST and additionally after 1 and 2 years for ORA. Results: The corneal resistance factor decreased significantly postoperatively (5.8 ± 1.7 mm Hg) compared with preoperatively (6.75 ± 3.7 mm Hg; P = 0.021) and increased again during follow-up (6.2 ± 1.9 mm Hg; P = 0.024), without regaining preoperative values. Corneal hysteresis and Keratoconus Match Index did not change significantly. Stiffness parameter A1 (P = 0.045) increased significantly after ICRS implantation and Arth decreased significantly from 181 ± 85 to 150 ± 92 (P = 0.016). However, there was no significant postoperative change for others Corvis parameters. Conclusions: Corneal biomechanical properties showed inconsistent changes after ICRS implantation. Classical corneal biomechanical parameters (using single central air-puff tonometers) do not seem to be suitable for follow-up after ICRS implantation.

show abstract

“…[ 3 8 9 10 ] Regarding tomography, there is consensus in the existing literature that ICRS implantation causes flattening of the cornea, thereby reducing myopic refraction and finally improving the uncorrected and corrected distance visual acuity of KC patients. [ 3 11 12 13 ] The mechanism of action of ICRS has been described via an arc-shortening effect within the cornea due to the added implant volume in the cornea. [ 14 ] An additional “artificial-limbus effect” caused by continuous ICRS has also been reported.…”

mentioning

confidence: 99%

Evaluation of dynamic corneal response parameters and the biomechanical E-staging after Intacs® SK implantation in keratoconus

Flockerzi,

Berger,

Seitz

et al. 2024

Indian Journal of Ophthalmology

View full text Add to dashboard Cite

Purpose: This retrospective longitudinal study evaluated the biomechanical E-staging in KC corneas before and after intracorneal ring segment (ICRS) implantation (Intacs® SK, Addition Technology, Illinois, United States). Methods: Biomechanical E-staging for ectatic corneal diseases was applied retrospectively on 49 KC corneas of 41 patients who underwent ICRS implantation. The main outcome parameters included the Corvis Biomechanical Factor (CBiF, the linearized Corvis Biomechanical Index and the biomechanical parameters included), the resulting biomechanical E-staging, the stress-strain index, thinnest corneal thickness (TCT), maximal anterior keratometry (Kmax), and the anterior radius of curvature (ARC). They were evaluated at 1.9 ± 1.1 months preoperatively and postoperatively after 2.8 ± 0.7, 5.8 ± 1.0, and 10.6 ± 2.3 months. Results: The CBiF decreased (4.9 ± 0.5 | 4.7 ± 0.5, P = 0.0013), and the E-staging increased significantly (2.8 ± 0.8 | 3.1 ± 0.9, P = 0.0012, paired t-test) from preoperatively to the first postoperative follow-up. The difference remained significant after 6 months; however, there was no more difference after 11 months. TCT was stable, whereas Kmax and ARC significantly decreased after ICRS implantation (TCT: 464 ± 49, 470 ± 51, 467 ± 38, 461 ± 48; Kmax: 56.3 ± 4.5, 54.7 ± 4.5, 54.2 ± 4.8, 54.1 ± 4.3; ARC: 51.5 ± 3.4, 48.3 ± 3.8, 48.6 ± 3.0, 48.6 ± 3.2 preoperatively and 3, 6, and 11 months postoperatively, respectively). Besides Kmax and ARC, Ambrósio’s relational thickness to the horizontal profile (ARTh) was the only parameter that was significantly lower than preoperatively at any follow-up (P ≤ 0.0024, Wilcoxon matched-pairs test). Conclusion: Intacs® SK implantation results in an increasing biomechanical E-staging in the first postoperative months with stabilization near preoperative values after 1 year. Significantly lower ARTh values at any follow-up document the ICRS effect and contribute to a slightly higher postoperative biomechanical E-staging value.

show abstract

Results of intrastromal corneal ring segment implanted alone or combined with same-day corneal crosslinking and their correlation with preoperative corneal biomechanical strain from finite element analysis

Abstract: To compare the results of intrastromal corneal ring segment (ICRS) alone or combined with same-day corneal crosslinking (CXL) and investigate the relationship of preoperative corneal biomechanics data on the outcomes.

Cited by 5 publications

References 20 publications

Asymmetric Intrastromal Corneal Ring Segments with Progressive Base Width and Thickness for Keratoconus: Evaluation of Efficacy and Analysis of Epithelial Remodeling

Asymmetric Intrastromal Corneal Ring Segments with Progressive Base Width and Thickness for Keratoconus: Evaluation of Efficacy and Analysis of Epithelial Remodeling

Implantation of Intracorneal Ring Segments in Keratectasia: Effects on Corneal Biomechanics in 112 Eyes

Evaluation of dynamic corneal response parameters and the biomechanical E-staging after Intacs® SK implantation in keratoconus

Contact Info

Product

Resources

About