Single Intacs segment for post-laser in situ keratomileusis keratectasia

Pokroy, Russell; Levinger, Samuel; Hirsh, Ami

doi:10.1016/j.jcrs.2004.02.050

Cited by 57 publications

(37 citation statements)

References 21 publications

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“…In addition, no significant decrease in ke ratometric astigma tism was reported in Group A (mean change, -1.66); in contrast, it was significant in group B (mean change, -2.78). The significant as tigmatic reduction found in our study supports the findings of previous studies (19,20) . With regard to BSCVA, only Group B showed significant improvement at the last postoperative follow-up visit.…”

Section: Discussionsupporting

confidence: 93%

Intrastromal corneal ring segment implantation for ectasia after refractive surgery

Stival

Nassaralla

Figueiredo

et al. 2015

Arquivos Brasileiros De Oftalmologia

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Purpose: To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct ectasia in eyes with prior refractive surgery. Methods: Forty-one eyes of 25 patients (13 men, 12 women; mean age, 28.66 years) with ectasia after refractive surgery [photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK)] were included in a nonrandomized, retrospective, observational case series. Corneal tunnels were created by mechanical dissection in all eyes. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), refraction, keratometry, and computerized analysis of corneal topography. Patients were divided into two groups by the type of refractive surgery (Group A: PRK, Group B: LASIK). Results:The mean preoperative manifest astigmatism decreased from -1.88 to -0.84 D in Group A (p=0.096) and -3.18 to -1.77 D in Group B (p=0.000). The mean keratometric astigmatism decreased from -2.58 to -1.66 D in Group A (p=0.010) and -4.80 to -2.78 D in Group B (p=0.000). The mean spherical equivalent decreased from -2.97 to -2.05 D in Group A (p=0.065) and -3.31 to -2.42 D in Group B (p=0.014). No significant between-group differences were noted on the comparison of preoperative and postoperative results. No intraoperative or postoperative com plications were observed. Conclusion: ICRS implantation is a useful treatment option for ectasia following refractive surgery, and it has significantly reduced the refractive cylinder and increased best spectacle-corrected visual acuity.

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Section: Discussionsupporting

confidence: 93%

Intrastromal corneal ring segment implantation for ectasia after refractive surgery

Stival

Nassaralla

Figueiredo

et al. 2015

Arquivos Brasileiros De Oftalmologia

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“…13,15,16 In rare cases, INTACS implantation could not resolve ectatic changes in keratoconus and after LASIK surgery. It is unclear what factors contribute to progressing ectasia after INTACS and what reaction INTACS implantation elicits in the corneal stroma at the molecular level.…”

Section: Conclusion-abnormalmentioning

confidence: 99%

“…10,11 Midstromal semicircular channels for INTACS ring insertion are created by a mechanical system with a blunt spiral device. 1,12,13 Despite the streamlined mechanistic procedure, attempts were made to improve control over the depth and shape of the channels. A femtosecond laser mounted on a delivery system capable of creating an intrastromal pattern of virtually any shape was recently used to create channels for INTACS insertion.…”

Section: Introductionmentioning

confidence: 99%

Alterations of Extracellular Matrix Components and Proteinases in Human Corneal Buttons With INTACS for Post-Laser In Situ Keratomileusis Keratectasia and Keratoconus

Maguen¹,

Rabinowitz²,

Regev³

et al. 2008

Cornea

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Purpose-To perform an immunohistochemical evaluation of corneas with INTACS for post-laser in situ keratomileusis (LASIK) keratectasia and keratoconus, obtained after corneal transplantation.Methods-Corneas from 1 patient with INTACS for post-LASIK keratectasia and 2 patients with INTACS for keratoconus were obtained within 3 hours after penetrating keratoplasty, and cryostat sections were analyzed by immunostaining for 35 extracellular matrix (ECM) components and proteinases.Results-In the stroma of all corneas next to an INTACS implant, ECM components typically associated with fibrosis were observed. These included tenascin-C, fibrillin-1, and types III, IV (α1/ α2 chains), and XIV collagen. Also, significant deposition of perlecan, nidogen-2, and cellular fibronectin was revealed in the same locations. The keratoconus cases displayed typical Bowman layer breaks and subepithelial fibrosis with deposition of various ECM components. In all cases, some keratocytes around INTACS were positive for specific proteinases associated with stromal remodeling, including cathepsins F and H, matrix metalloproteinase (MMP)-1, MMP-3, and MMP-10. Staining for MMP-7 was variable; MMP-2 and MMP-9 were mostly negative. Patterns of type IV collagen α3, α4, and α6 chains; types VI and VIII collagen;α4, α5,β1, β2, and γ1 laminin chains; vitronectin; thrombospondin-1; urokinase; EMMPRIN; and cathepsins B and L were unchanged around INTACS in all 3 cases compared with normal. Recently, INTACS has acquired new interest as an alternative treatment of keratoconus. [5][6][7][8][9][10] The rationale is that INTACS not only flattens the central cornea but also corrects some of the astigmatic component. The corneal profile becomes more symmetrical, usually allowing better correction with glasses and contact lenses. Given that, for these patients, the alternative would be penetrating keratoplasty, INTACS may delay the need for this option. 10,11 Midstromal semicircular channels for INTACS ring insertion are created by a mechanical system with a blunt spiral device. 1,12,13 Despite the streamlined mechanistic procedure, attempts were made to improve control over the depth and shape of the channels. A femtosecond laser mounted on a delivery system capable of creating an intrastromal pattern of virtually any shape was recently used to create channels for INTACS insertion. 10 This method may be technically easier and more precise, reflecting better final outcomes. Conclusions-AbnormalKeratectasia is a rare but serious complication of laser vision correction of any refractive errors. It occurs mostly after LASIK but was also described after surface excimer laser ablation (photorefractive keratectomy). 14-16 It involves severe refractive changes mostly occurring several years after the surgery, which are caused by thinning and sagging of the corneal profile, similar to keratoconus.The etiology of this complication remains uncertain. In some cases, preexisting forme fruste keratoconus was documented. 17,18 Other cases could be caused by a me...

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“…[5][6][7][8][9] Colin et al 1,2 in 10 eyes and Boxer Wachler et al 3 in 74 eyes, in an attempt to treat the inferior ectasia characteristic of keratoconus, used an asymmetric technique, implanting an inferior 0.45-mm segment and a superior 0.25-mm segment through a temporal incision. In 33 keratoconic eyes, Siganos et al 4 used a symmetric technique, implanting 2 same-thickness segments in a technique similar to that used to correct low myopia.…”

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confidence: 99%

Keratoconus Managed With Intacs

Levinger¹

2005

Arch Ophthalmol

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To describe the visual outcome of keratoconus managed with Intacs implantation (Addition Technology Inc, Fremont, Calif) and to define criteria that predict good outcome.Methods: This retrospective, nonrandomized, comparative, consecutive case series studied 58 eyes of 43 patients with keratoconus managed by Intacs implantation. The outcome measures were analyzed pre-Intacs and 1 year post-Intacs. Preoperative parameters were correlated with outcome.Main Outcome Measures: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, videokeratography, and patient questionnaires.Results: Intacs were implanted in all eyes with no in-traoperative complications. Six eyes underwent additional Intacs surgery. Post-Intacs, the mean±SD UCVA improved from less than 20/200 ± 0.1 line to 20/ 50 −3 ±3.1 lines, the mean±SD BSCVA was unchanged at 20/32±2.0 lines, the mean±SD spherical equivalent improved from −3.88±1.64 to −1.04±1.51 diopters (D), and the mean±SD astigmatism improved from 3.34±2.23 to 1.97 ± 1.51 D. Twenty-five eyes had a good outcome (UCVAՆ20/40). Multiple regression selected BSCVA, astigmatism, and spherical myopia as the preoperative predictors of outcome.Conclusions: Intacs improve myopia and regular astigmatism in keratoconus. Milder keratoconus (BSCVAϾ20/ 32 −2 and astigmatismϽ3.50 D) and significant spherical myopia (Ͼ−1.75) predict better outcome.

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Single Intacs segment for post-laser in situ keratomileusis keratectasia

Abstract: Implantation of a single Intacs segment inferiorly appeared to improve progressive myopia and regular and irregular astigmatism in eyes with corneal ectasia after LASIK. With further study, this technique may prove to be an effective, relatively noninvasive approach.

Cited by 57 publications

References 21 publications

Intrastromal corneal ring segment implantation for ectasia after refractive surgery

Intrastromal corneal ring segment implantation for ectasia after refractive surgery

Alterations of Extracellular Matrix Components and Proteinases in Human Corneal Buttons With INTACS for Post-Laser In Situ Keratomileusis Keratectasia and Keratoconus

Keratoconus Managed With Intacs

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