Clinical Outcomes of Femtosecond Laser–Assisted Implantation of Asymmetric ICRS in Keratoconus With No Coincidence of Topographic and Comatic Axes

Kammoun, H.; Piñero, David P.; Toledo, Juan Álvarez de; Barraquer, Rafael I.; Oteyza, G. García de

doi:10.3928/1081597x-20210712-04

Cited by 9 publications

(8 citation statements)

References 27 publications

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“…[ 1 2 3 4 5 6 7 8 9 10 11 ] However, many topographical characteristics make customization of intrastromal segments more desirable. [ 24 25 26 27 28 29 30 31 ] In this case series, we created tapered segments for patients with pericentral or paracentral decentered cones who showed gradation of keratometric values with one side being steeper than the other. We attempted to do this by varying the volume of tissue implanted in different zones – adding more volume where greater flattening was required and less where less flattening was required.…”

Section: Discussionmentioning

confidence: 99%

“…Asymmetric synthetic ICRS have previously been reported to regularize the corneal shape and result in appreciable visual improvement in patients with a significant difference between corneal topographic and comatic axes. [ 25 26 27 28 29 30 31 ] These asymmetric segments are available as fixed combinations of arc length, diameter, thickness variation, width variation, and in clockwise and anti-clockwise versions. Moreover, the thickness changes at a uniform rate from one end to the other, without varying stretches of uniform thickness as we were able to do in the case of CAIRS.…”

Section: Discussionmentioning

confidence: 99%

“…This advantage of a high level of customization would not be possible with synthetic asymmetric ICRS. Even with the disadvantage of only fixed combinations being available, a large inventory of synthetic segments is needed to be maintained, with different arc lengths and optic zones, thicknesses and widths,[ 25 26 27 28 29 30 31 ] whereas customized CAIRS can be easily cut on the spot by the surgeon or rapidly provided pre-cut as per plan by eye banks.…”

Section: Discussionmentioning

confidence: 99%

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Customized corneal allogenic intrastromal ring segments (CAIRS) for keratoconus with decentered asymmetric cone

Jacob,

Agarwal,

Awwad

et al. 2023

Indian Journal of Ophthalmology

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Corneal allogenic intrastromal ring segments (CAIRS) refer to the intracorneal placement of fresh, unprocessed, processed, preserved, or packaged allogenic rings/segments of any type/length. We described uniform-thickness CAIRS previously. We now describe a new technique of customized CAIRS to personalize the flattening effect as per individual topography. A prospective interventional case series of patients with pericentral/ paracentral decentered cones and gradation of keratometry with one side steeper than the other was conducted. Individually customized tapered CAIRS with variable volume, arc length, taper length, and gradient of taper were implanted. In total, 32 eyes of 29 patients with at least 1-year follow-up were included. Special double-bladed trephines and a CAIRS customizer template allowed the creation of individually customized CAIRS. Mean uncorrected distance visual acuity (UDVA) and spectacle-corrected distance visual acuity improved from 0.22 to 0.47 (P = 0.000) and from 0.76 to 0.89 (P = 0.001), respectively. Significant improvement was seen in K1, K2, Km, Kmax, topographic astigmatism, Q-value, sphere, cylinder, spherical equivalent, Root Mean Square (RMS), Higher Order Aberrations (HOA), and vertical coma (P < 0.01, 0.05). There was no significant change in the width or height of CAIRS between 1 month and last visit on anterior-segment optical coherence tomography. Five eyes continued to remain at the same UDVA, 27 eyes had at least 2 lines, and 13 eyes had at least 3 or more lines improvement in UDVA. The maximum improvement in UDVA was 7 lines. A significant difference in flattening was obtained at different zones across the tapered CAIRS. Thus, differential flattening was achieved across the cone based on the customization plan. Personalized customization was possible for each cornea, unlike limited models of progressive-thickness synthetic segments. Allogenic nature, greater customizability, efficacy, and absent need for large inventories are advantages compared to synthetic segments.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Customized corneal allogenic intrastromal ring segments (CAIRS) for keratoconus with decentered asymmetric cone

Jacob,

Agarwal,

Awwad

et al. 2023

Indian Journal of Ophthalmology

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“…In fact, there are two papers that study the impact of ICRS in the “duck” phenotype. Alfonso et al studied the symmetric ICRS [ 25 ], and Kammoun et al used an asymmetric ICRS, the same as modelled in our current study [ 26 ]. In their study, Alfonso observed an overall reduction in sphere, cylinder, and spherical equivalent in most of the patients, but the results did not reach statistical significance.…”

Section: Discussionmentioning

confidence: 99%

Localized Refractive Changes Induced by Symmetric and Progressive Asymmetric Intracorneal Ring Segments Assessed with a 3D Finite-Element Model

García de Oteyza,

Álvarez de Toledo,

Barraquer

et al. 2023

Bioengineering

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To build a representative 3D finite element model (FEM) for intracorneal ring segment (ICRS) implantation and to investigate localized optical changes induced by different ICRS geometries, a hyperelastic shell FEM was developed to compare the effect of symmetric and progressive asymmetric ICRS designs in a generic healthy and asymmetric keratoconic (KC) cornea. The resulting deformed geometry was assessed in terms of average curvature via a biconic fit, sagittal curvature (K), and optical aberrations via Zernike polynomials. The sagittal curvature map showed a locally restricted flattening interior to the ring (Kmax −11 to −25 dpt) and, in the KC cornea, an additional local steepening on the opposite half of the cornea (Kmax up to +1.9 dpt). Considering the optical aberrations present in the model of the KC cornea, the progressive ICRS corrected vertical coma (−3.42 vs. −3.13 µm); horizontal coma (−0.67 vs. 0.36 µm); and defocus (2.90 vs. 2.75 µm), oblique trefoil (−0.54 vs. −0.08 µm), and oblique secondary astigmatism (0.48 vs. −0.09 µm) aberrations stronger than the symmetric ICRS. Customized ICRS designs inspired by the underlying KC phenotype have the potential to achieve more tailored refractive corrections, particularly in asymmetric keratoconus patterns.

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“…The thickness or width of these segments varies so as to treat the keratoconus heterogeneously, targeting certain areas of the cornea, according to the phenotype. Asymmetric ICRS implantation has resulted in good visual, refractive and topographic outcomes, with a particularly large decrease in coma-like aberration [ 6 , 9 , 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

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

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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.

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Clinical Outcomes of Femtosecond Laser–Assisted Implantation of Asymmetric ICRS in Keratoconus With No Coincidence of Topographic and Comatic Axes

Cited by 9 publications

References 27 publications

Customized corneal allogenic intrastromal ring segments (CAIRS) for keratoconus with decentered asymmetric cone

Customized corneal allogenic intrastromal ring segments (CAIRS) for keratoconus with decentered asymmetric cone

Localized Refractive Changes Induced by Symmetric and Progressive Asymmetric Intracorneal Ring Segments Assessed with a 3D Finite-Element Model

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

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