Intracorneal rings to correct corneal ectasia after laser in situ keratomileusis

Alió, Jorge L.; Salem, Tamer; Artola, Alberto; Osman, A. A.

doi:10.1016/s0886-3350(01)01275-5

Cited by 131 publications

(80 citation statements)

References 10 publications

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“…[1][2][3][4][5][6][7][8][9][10]12,15,32,33 The procedure is generally safe, with only rare cases of corneal infections. 34 Morphologic studies have shown local stromal reaction with keratocyte activation, lipid accumulation, moderate fibrosis, mild epithelial changes, and formation of new collagen and hypocellular scars.…”

Section: Discussionmentioning

confidence: 99%

“…It occurs mostly after LASIK but was also described after surface excimer laser ablation (photorefractive keratectomy). [14][15][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.…”

mentioning

confidence: 99%

“…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.…”

mentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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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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“…1,2 FDA-approved 3 intrastromal corneal ring segments (ICRS) have been found beneficial for the treatment of KC and corneal ectasia following refractive surgery [4][5][6] as they flatten and regularize the cornea by means of an arc shortening effect. 7 The most common types of ICRS used in clinical practice are Intacs (Addition Technology, Inc., Sunnyvale, CA, USA) and Ferrara rings (Ferrara Ophthalmics, Brazil).…”

Section: Introductionmentioning

confidence: 99%

Depth evaluation of intended vs actual intacs intrastromal ring segments using optical coherence tomography

Barbara

Naftali

2015

Eye

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Purpose Evaluation of actual vs intended intrastromal corneal ring segments (ICRS) implantation depth as measured by anterior segment optical coherence tomography (OCT) Methods Prospective study evaluating 30 Intacs segments implanted manually in 19 eyes of 15 patients suffering from keratoconus. Segment depth evaluation was performed using anterior segment OCT. Measurements were performed above and below the segment at 3 points in relation to the incision site. Statistical analysis was performed using the SAS software for ANOVA, matched t-test, and GLIMMIX procedure. Results Intacs segment depth was 153-μm shallower than intended (58% vs 80%). Segment layout demonstrated the proximal and distal portions to be 13-μm shallower and 12-μm deeper (on average), respectively. Intacs segment thickness does not influence implantation depth. Intacs segments implanted in the same eye do not share similar implantation depths. Stromal compression is likely to occur. Conclusion Intacs are implanted at a shallower depth than intended. The 'pocketing' stage prior to implantation most likely has a stronger effect on the segment's final implantation depth than does the incisions' depth.

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“…At present, there are several options to treat corneal ectatic diseases before a corneal transplant. A surgical alternative method to stabilize or delay the progression of the ectatic disease involves the implantation of intracorneal ring segments [3][4][5]. According to the postulates of Barraquer [6] and Blavatskaya [7], the intracorneal ring segments implanted in the corneal stroma lead to a flattening on the corneal surface.…”

Section: Introductionmentioning

confidence: 99%

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

et al. 2010

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a b s t r a c tThe objective of this work was to evaluate the potential use of less stiff materials based on acrylic copolymers of methyl methacrylate/2-ethylhexyl acrylate (MMA/EHA) as devices to correct, stabilize and improve the effect of poly(methyl methacrylate) (PMMA) intracorneal ring segments. MMA/EHA and PMMA intracorneal ring segments were surgically implanted in the corneas of Lohmann Classic hens. The effects of the intracorneal ring segments were assessed by optical measurements and corneal tolerance was evaluated through biomicroscopic examination over a 90-day observation period and by conventional histology. The experimental results demonstrated that the intracorneal ring segments made of MMA/EHA copolymers provided a significant change in the corneal curvature and an improved in vivo response compared to those obtained for PMMA rings, which was attributed to the higher flexibility of the copolymeric materials, indicating that these systems might be considered suitable as an alternative to those currently used, for application in clinical practice.

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Intracorneal rings to correct corneal ectasia after laser in situ keratomileusis

Abstract: Intacs intrastromal corneal rings used as a mechanical device may alter the biomechanical properties of the cornea for the correction of iatrogenic keratectasia and the associated residual myopia.

Cited by 131 publications

References 10 publications

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

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

Depth evaluation of intended vs actual intacs intrastromal ring segments using optical coherence tomography

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

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