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Utine CA, Özizmirliler D, Kayabaşı M, Günenç Ü. The number of intracorneal ring segments in asymmetric and central cones. EYE AND VISION (LONDON, ENGLAND) 2021; 8:10. [PMID: 33785054 PMCID: PMC8010988 DOI: 10.1186/s40662-021-00234-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 03/07/2021] [Indexed: 12/03/2022]
Abstract
Background To compare the results of single versus double intracorneal ring segment (ICRS) (KeraRing) implantation in keratoconus with respect to different cone locations. Methods Twenty-two eyes of 18 patients with totally asymmetric cones (20–80% or 0–100% distribution along steep axis) were implanted with single ICRS (Group 1), 38 eyes of 32 patients with central or partially asymmetric cones (50–50% or 40–60% distribution along steep axis) were implanted with double ICRS (Group 2), at a depth of 80% of the site of implantation, in channels created with femtosecond laser device. All patients had uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively) of ≤ 0.3 Snellen lines. Results In both groups, patients had median UDVA and CDVA gain of 3 Snellen lines (P > 0.05). Postoperative improvement in indices of vertical asymmetry and height decentration in Group 1; simulated keratometry, corneal astigmatism and anterior corneal asphericity values in Group 2 were greater (P < 0.05). A total of 10 eyes (45.5%) in Group 1 were recommended double ring implantation by the manufacturer’s nomogram, but underwent single ICRS implantation and achieved visual, refractive, tomographic outcomes comparable to that in Group 2, although corneal cylindrical correction was less and final topographic astigmatism was greater. Conclusion Double ICRS implantation seems to be superior in terms of keratometry, corneal astigmatism and anterior corneal asphericity improvement. Single ICRS implantation in totally asymmetric cones seems to provide satisfactory visual, refractive and tomographic results, similar to double ICRS implantation in central and partially asymmetric cones, by inducing central shift of the cone.
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Affiliation(s)
- Canan Asli Utine
- Department of Ophthalmology, Faculty of Medicine, Dokuz Eylul University, Mithatpasa cad, No:1606 Inciraltı Kampusu, Balcova, 35330, Izmir, Turkey. .,Izmir Biomedicine and Genome Center, Izmir, Turkey.
| | - Denizcan Özizmirliler
- Department of Ophthalmology, Faculty of Medicine, Dokuz Eylul University, Mithatpasa cad, No:1606 Inciraltı Kampusu, Balcova, 35330, Izmir, Turkey
| | - Mustafa Kayabaşı
- Department of Ophthalmology, Faculty of Medicine, Dokuz Eylul University, Mithatpasa cad, No:1606 Inciraltı Kampusu, Balcova, 35330, Izmir, Turkey
| | - Üzeyir Günenç
- Department of Ophthalmology, Faculty of Medicine, Dokuz Eylul University, Mithatpasa cad, No:1606 Inciraltı Kampusu, Balcova, 35330, Izmir, Turkey
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Averich VV, Avetisov KS, Alkhumidi K, Avetisov SE. [Phacosurgery features in keratoconus]. Vestn Oftalmol 2020; 136:296-300. [PMID: 33063980 DOI: 10.17116/oftalma2020136052296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The review summarizes the results of surgical treatment of cataracts in patients with keratoconus. The major challenges of phacosurgery in keratoconus are associated with intraocular lens (IOL) power calculation, choice of the most appropriate IOL model and additional interventions required to stabilize keratectasia and reduce corneal irregularity.
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Affiliation(s)
- V V Averich
- Research Institute of Eye Diseases, Moscow, Russia
| | - K S Avetisov
- Research Institute of Eye Diseases, Moscow, Russia
| | - K Alkhumidi
- Research Institute of Eye Diseases, Moscow, Russia
| | - S E Avetisov
- Research Institute of Eye Diseases, Moscow, Russia.,I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
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[Reliability of corneal tomography after implantation of intracorneal ring segments for keratoconus]. Ophthalmologe 2020; 117:1092-1099. [PMID: 32140771 PMCID: PMC7644543 DOI: 10.1007/s00347-020-01074-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND AND OBJECTIVE Intracorneal ring segments (ICRS) are believed to stop the progression of keratoconus (KC). This statement on progression, however, requires knowledge about measurement reproducibility. The purpose of this study was to compare the reproducibility of tomographic parameters in eyes with KC after femtosecond laser-assisted implantation of INTACS (fs-INTACS) using two different devices and to determine which is more reliable for the follow-up of these patients. PATIENTS AND METHODS In this study 19 KC eyes were included and repeatedly examined 5 times with the Scheimpflug topography Pentacam HR and the Casia 2 optical coherence tomography (VA-OCT) devices. Outcome measures included the reproducibility and comparability of measurements between the two devices of (1) keratometric refractive power of the anterior cornea and (2) posterior cornea, (3) maximum keratometric refractive power, (4) central corneal thickness and (5) corneal thickness at the thinnest site. RESULTS The mean differences (Pentacam minus Casia 2) of (1), (2), (3), (4) and (5) were 0.67 dpt, 0.41 dpt, 3.4 dpt, 1.5 µm and 11.8 µm, respectively. The mean SDs of the 5 repeat measurements for (1), (2), (3), (4) and (5) were 0.20 dpt/0.20 dpt, 0.10 dpt/0.07 dpt, 0.75 dpt/0.5 dpt, 6.5 µm/2.4 µm (p = 0.007) and 7.3 µm/1.9 µm (p = 0.001) for Pentacam and Casia 2, respectively. Cronbach's alpha was better than 0.98 for both devices and all parameters. CONCLUSION Both Casia 2 and Pentacam enable a reliable assessment of the corneal refractive power in KC after fs-INTACS implantation; however, the reproducibility was significantly better with Casia 2 only for the measurement of corneal thickness. The Pentacam showed significantly higher values for the mean anterior and posterior corneal refractive power and measured significantly thicker at the thinnest point of the cornea compared to Casia 2.
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Sakellaris D, Balidis M, Gorou O, Szentmary N, Alexoudis A, Grieshaber MC, Sagri D, Scholl H, Gatzioufas Z. Intracorneal Ring Segment Implantation in the Management of Keratoconus: An Evidence-Based Approach. Ophthalmol Ther 2019; 8:5-14. [PMID: 31605316 PMCID: PMC6789055 DOI: 10.1007/s40123-019-00211-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Indexed: 01/19/2023] Open
Abstract
Intracorneal ring segment (ICRS) implantation represents a modern, minimally invasive, surgical option for visual improvement in patients with keratoconus. ICRS modify the corneal geometry in a manner that enhances its refractive properties and thereby, they improve visual acuity. It is well-documented that implantation of ICRS decreases the keratometric readings, spherical equivalent and cylinder, reduces high-order aberrations and improves uncorrected distance visual acuity (UDVA) and best-corrected distance visual acuity (BCDVA) in patients with keratoconus. Success rate after ICRS implantation is high, depending on appropriate patient selection and adherence to suitable implantation nomograms, and most important, the overall complication rate is very low. This review is summarizing current indications/contra-indications for ICRS implantation, implantation techniques, clinical outcomes and potential complications, shedding light on myths and realities related to this innovative surgical option.
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Affiliation(s)
| | | | - Olga Gorou
- Ophthalmica Institute, Thessaloniki, Greece
| | - Nora Szentmary
- Department of Ophthalmology, University Clinic Saarland, Homburg, Saarland, Germany
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Antonios Alexoudis
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | | | | | - Hendrik Scholl
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Zisis Gatzioufas
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland.
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Monteiro T, Alfonso JF, Freitas R, Franqueira N, Faria-Correira F, Ambrósio R, Madrid-Costa D. Comparison of Complication Rates between Manual and Femtosecond Laser-Assisted Techniques for Intrastromal Corneal Ring Segments Implantation in Keratoconus. Curr Eye Res 2019; 44:1291-1298. [PMID: 31226888 DOI: 10.1080/02713683.2019.1635165] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Purpose: To compare the incidence of complications between manual and femtosecond-laser assisted surgery for intrastromal corneal ring segments (ICRS) implantation.Material and methods: This study included keratoconus patients who had ICRS implantation using manual dissection and using the femtosecond laser with a minimum follow-up of 12 months. Uncorrected (UDVA) corrected (CDVA) distance visual acuity (CDVA), refraction, corneal topography and aberrometry, pachymetry map and slit-lamp microscopy were assessed before and after surgery.Results: The study included 265 eyes in the manual group and 111 in the femtosecond laser group. In the manual group, there were complications in 48 eyes (18.11%); while in the femtosecond laser 4 eyes had a complication (3.6%). In the manual group, the most frequent complications were ICRS exchange/adjustment for visual and refractive enhancement (25 eyes; 9.43%) and late ICRS spontaneous extrusion (15 eyes; 5.66%). In the manual group, 81.25% of complications were observed during the first 3 years of surgeon's experience. Eyes who suffered a complication had preoperatively higher mean refractive (p = .002) and topographic cylinder (p = .003) and lower UDVA (p = .005) and CDVA (p = .002). After a second surgical procedure for complication management visual, refractive and topographic outcomes significantly improved.Conclusion: Manual mechanical ICRS surgery shows a higher rate of intra- and postoperative mechanical and refractive complications when compared to femtosecond laser assisted technique. The incidence is specially higher during the surgeon's first years of implementation of the technique.
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Affiliation(s)
- Tiago Monteiro
- Ophthalmology Department, Hospital de Braga, Braga, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - José F Alfonso
- Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, Oviedo, Spain
| | - Rui Freitas
- Ophthalmology Department, Hospital de Braga, Braga, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Nuno Franqueira
- Ophthalmology Department, Hospital de Braga, Braga, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Fernando Faria-Correira
- Ophthalmology Department, Hospital de Braga, Braga, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Renato Ambrósio
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.,Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - David Madrid-Costa
- Optometry and Vision Department, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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Pandolfi A, Gizzi A, Vasta M. A microstructural model of cross-link interaction between collagen fibrils in the human cornea. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180079. [PMID: 30879417 DOI: 10.1098/rsta.2018.0079] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 05/28/2023]
Abstract
We propose a simplified micromechanical model of the fibrous reinforcement of the corneal tissue. We restrict our consideration to the structural function of the collagen fibrils located in the stroma and disregard the other all-important components of the cornea. The reinforcing structure is modelled with two sets of parallel fibrils, connected by transversal bonds within the single fibril family (inter-cross-link) and across the two families (intra-cross-link). The particular design chosen for this ideal structure relies on the fact that its ability to sustain loads is dependent on the degree of the cross-link and, therefore, on the density and stiffness of the bonds. We analyse the mechanical response of the system according to the type of interlacing and on the stiffness of fibres and bonds. Results show that the weakening of transversal bonds is associated with a marked increase of the deformability of the system. In particular, the deterioration of transversal bonds due to mechanical, chemical or enzymatic reasons can justify the loss of stiffness of the stromal tissue resulting in localized thinning and bulging typically observed in keratoconus corneas. This article is part of the theme issue 'Rivlin's legacy in continuum mechanics and applied mathematics'.
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Affiliation(s)
- A Pandolfi
- 1 Dipartimento di Ingegneria Civile ed Ambientale, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan , Italy
| | - A Gizzi
- 2 Department of Engineering , University Campus Bio-Medico of Rome , Via A. del Portillo 21, Rome 00128 , Italy
| | - M Vasta
- 3 Dipartimento INGEO , Università di Chieti-Pescara , Viale Pindaro 42, Pescara , Italy
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Garcia-Ferrer FJ, Akpek EK, Amescua G, Farid M, Lin A, Rhee MK, Varu DM, Musch DC, Mah FS, Dunn SP. Corneal Ectasia Preferred Practice Pattern®. Ophthalmology 2019; 126:P170-P215. [DOI: 10.1016/j.ophtha.2018.10.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023] Open
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Two-year topographic and densitometric outcomes of accelerated (45 mW/cm 2) transepithelial corneal cross-linking for keratoconus: a case-control study. BMC Ophthalmol 2018; 18:337. [PMID: 30587181 PMCID: PMC6307285 DOI: 10.1186/s12886-018-0999-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 12/05/2018] [Indexed: 12/13/2022] Open
Abstract
Background Conventional corneal cross-linking is effective for retarding the progression of keratoconus. However the long-term efficacy and safety of accelerated (45 mW/cm2) transepithelial corneal cross-linking (ATE-CXL) on progressive keratoconus (KC) treatment is not fully understood. The purpose of this study is to evaluate the 2-year changes in corneal topographic parameters and densitometry values after ATE-CXL for KC. Methods Twenty-five progressive eyes of 25 KC patients (KC group) and 25 eyes of 25 myopes without KC (control group) were enrolled. Corneal topography and densitometry values were evaluated pre-operatively and at 6, 12 and 24 months post-operatively in the KC group. Results The mean values of flat keratometry (K1), steep keratometry (K2), mean keratometry (Km), corneal astigmatism (CA), maximum keratometry (Kmax), central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior corneal elevation (ACE) and posterior corneal elevation (PCE) all remained unchanged over time (all P values > 0.05). The densitometry values of the anterior, central, posterior and total layers over the annular diameters 0 mm to 2 mm (Φ0-2 mm) and Φ2–6 mm all decreased significantly (all P values < 0.05). At post-operative month 24, except for the densitometry value of the posterior layer (Φ0-2 mm), which was significantly lower than that of the control group (post hoc P = 0.010), all densitometry values obtained from the remaining locations of the KC eyes were equal to those of the control group (All post hoc P values > 0.05). Subgroups with Km ≥ 50.30D or ACE ≥35.3 μm progressed significantly when compared with those with Km < 50.30D (F = 8.167, P = 0.004) or ACE< 35.3 μm (F = 5.207, P = 0.022). Conclusions K1, K2, Km, CA, Kmax, CCT, TCT, ACE, and PCE values may remain stable but severer KC patients tend to have poorer long-term outcomes. The densitometry values of the full corneal thickness (total layer over Φ0-2 mm and Φ2–6 mm) may decrease to normal levels at 2 years after ATE-CXL for KC.
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Outcome of Keratoconus Management: Review of the Past 20 Years' Contemporary Treatment Modalities. Eye Contact Lens 2017; 43:141-154. [DOI: 10.1097/icl.0000000000000270] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Hydrogel ocular sealant for wound closure during intrastromal corneal ring segment implantation. J Cataract Refract Surg 2016; 42:515-9. [DOI: 10.1016/j.jcrs.2016.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 02/24/2016] [Accepted: 03/06/2016] [Indexed: 11/21/2022]
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Vega-Estrada A, Alio JL. The use of intracorneal ring segments in keratoconus. EYE AND VISION 2016; 3:8. [PMID: 26981548 PMCID: PMC4791885 DOI: 10.1186/s40662-016-0040-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 03/06/2016] [Indexed: 12/31/2022]
Abstract
Keratoconus is a corneal degeneration that usually appears during puberty and may seriously deteriorate the quality of life of the patients. This corneal disease is today the first indication of corneal transplantation in young patients. Until the last decade of the XX century, keratoplasty procedures were the only alternative to treat this pathological condition. In the beginning of the XXI century, intracorneal ring segments implantation was proposed as a therapeutic choice for treating keratoconus patients. Since then, several published articles have reported the benefits of this surgical procedure in treating this type of corneal ectatic disorder. The purpose of the present investigative work is to summarize the characteristic of the intracorneal ring segments and also to review the different features published in the literature in relation to this surgical technique for the treatment of keratoconus patients.
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Affiliation(s)
- Alfredo Vega-Estrada
- Keratoconus Unit, Vissum Alicante, Calle Cabañal, 1 Edificio Vissum, 03016 Alicante, Spain ; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain
| | - Jorge L Alio
- Keratoconus Unit, Vissum Alicante, Calle Cabañal, 1 Edificio Vissum, 03016 Alicante, Spain ; Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain
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Reshaping procedures for the surgical management of corneal ectasia. J Cataract Refract Surg 2015; 41:842-72. [PMID: 25840308 DOI: 10.1016/j.jcrs.2015.03.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/15/2014] [Accepted: 07/23/2014] [Indexed: 12/31/2022]
Abstract
UNLABELLED Corneal ectasia is a progressive, degenerative, and noninflammatory thinning disorder of the cornea. Recently developed corneal reshaping techniques have expanded the treatment armamentarium available to the corneal specialist by offering effective nontransplant options. This review summarizes the current evidence base for corneal collagen crosslinking, topography-guided photorefractive keratectomy, and intrastromal corneal ring segment implantation for the treatment of corneal ectasia by analyzing the data published between the years 2000 and 2014. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Chhadva P, Yesilirmak N, Cabot F, Yoo SH. Intrastromal Corneal Ring Segment Explantation in Patients With Keratoconus: Causes, Technique, and Outcomes. J Refract Surg 2015; 31:392-7. [PMID: 26046706 DOI: 10.3928/1081597x-20150521-05] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 04/17/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the causes for intrastromal corneal ring segment (Intacs; Addition Technology Inc., Lombard, IL) explantation in patients with keratoconus, and technique for explantation, long-term outcomes, and secondary procedures to correct visual acuity. METHODS Ten eyes of 8 patients with a history of Intacs explantation between 2004 and 2012 were included in a retrospective study performed at the Bascom Palmer Eye Institute, Miami, Florida. Causes of Intacs removal, surgical technique, preoperative and postoperative corneal examination, and uncorrected and corrected distance visual acuity were documented. Additionally, corneal topography (Tomey, Nagoya, Japan) parameters such as average keratometry and corneal cylinder were assessed. RESULTS Although the segments were well positioned, the most common cause of Intacs removal was worsening visual acuity (80%). There was no statistically significant difference between pre-Intacs placement, post-Intacs placement, and post-Intacs removal in uncorrected and corrected distance visual acuity, average keratometry, or corneal cylinder, except between 1-year post-Intacs placement corrected distance visual acuity (0.57 logMAR [20/75 Snellen]) and 1-month post-Intacs removal corrected distance visual acuity (0.25 logMAR [20/36 Snellen], P =.03). Four patients underwent penetrating keratoplasty after Intacs removal with good visual outcomes. CONCLUSION This study demonstrates the visual and structural outcomes that returned to near baseline after Intacs explantation in keratoconic eyes.
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Corneal Transplantation Activity Over 7 Years: Changing Trends for Indications, Patient Demographics and Surgical Techniques From the Corneal Transplant Epidemiological Study (CORTES). Transplant Proc 2015; 47:528-35. [DOI: 10.1016/j.transproceed.2014.10.040] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 10/06/2014] [Accepted: 10/27/2014] [Indexed: 11/20/2022]
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Intrastromal corneal ring segment implantation (keraring 355°) in patients with central keratoconus: 6-month follow-up. J Ophthalmol 2015; 2015:916385. [PMID: 25685395 PMCID: PMC4313675 DOI: 10.1155/2015/916385] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/27/2014] [Accepted: 11/28/2014] [Indexed: 11/17/2022] Open
Abstract
We evaluate the efficacy and safety of Keraring 355° intrastromal corneal ring segment (ICRS) implantation aided by PocketMaker microkeratome for the correction of keratoconus. Patients underwent ICRS insertion using mechanical dissection with PocketMaker microkeratome and completed 6 months of follow-up. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, topographic findings, safety, efficacy index, and adverse events were reported for six months postoperatively. We evaluated 15 eyes of 15 patients (12 men) with a mean age of 28.87 ± 6.94 years (range 21–49 years). At final postoperative examination, there was a statistically significant reduction in the spherical equivalent refractive error compared to preoperative measurements (−5.46 ± 1.52 to −2.01 ± 1.63 D, P < 0.001). Mean preoperative UCVA (logMAR) before implantation was 0.79 ± 0.48, and postoperative UCVA was 0.28 ± 0.15, P = 0.001. Mean preoperative BSCVA (logMAR) before implantation was 0.36 ± 0.21; at final follow-up examination BSCVA was 0.18 ± 0.9, P = 0.009. Mean K decreased from 48.33 to 43.31 D, P < 0.001. All patients were satisfied with ICRS implantation; 86.7% were moderately to very happy with the results. No intraoperative or postoperative complications were demonstrated. This preliminary study shows that ICRS (Keraring 355°) implantation is an efficient, cost-effective, and minimally invasive procedure for improving visual acuity in nipple type keratoconic corneas.
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Karamichos D, Hjortdal J. Keratoconus: tissue engineering and biomaterials. J Funct Biomater 2014; 5:111-34. [PMID: 25215423 PMCID: PMC4192608 DOI: 10.3390/jfb5030111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 08/26/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022] Open
Abstract
Keratoconus (KC) is a bilateral, asymmetric, corneal disorder that is characterized by progressive thinning, steepening, and potential scarring. The prevalence of KC is stated to be 1 in 2000 persons worldwide; however, numbers vary depending on size of the study and regions. KC appears more often in South Asian, Eastern Mediterranean, and North African populations. The cause remains unknown, although a variety of factors have been considered. Genetics, cellular, and mechanical changes have all been reported; however, most of these studies have proven inconclusive. Clearly, the major problem here, like with any other ocular disease, is quality of life and the threat of vision loss. While most KC cases progress until the third or fourth decade, it varies between individuals. Patients may experience periods of several months with significant changes followed by months or years of no change, followed by another period of rapid changes. Despite the major advancements, it is still uncertain how to treat KC at early stages and prevent vision impairment. There are currently limited tissue engineering techniques and/or "smart" biomaterials that can help arrest the progression of KC. This review will focus on current treatments and how biomaterials may hold promise for the future.
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Affiliation(s)
- Dimitrios Karamichos
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, DMEI PA-409, Oklahoma City, OK 73104, USA.
| | - Jesper Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C DK-800, Denmark.
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Haddad W, Fadlallah A, Dirani A, El Rami H, Fahd D, Khanafer D, Fahed S. Comparison of 2 types of intrastromal corneal ring segments for keratoconus. J Cataract Refract Surg 2012; 38:1214-21. [DOI: 10.1016/j.jcrs.2012.02.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/26/2012] [Accepted: 02/01/2012] [Indexed: 10/28/2022]
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Ancèle E, Malecaze F, Arné JL, Fournié P. Facteurs prédictifs de succès des anneaux intracornéens de Ferrara dans le kératocône. J Fr Ophtalmol 2011; 34:513-20. [DOI: 10.1016/j.jfo.2011.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Revised: 02/06/2011] [Accepted: 02/14/2011] [Indexed: 11/16/2022]
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Corneal Melt of Incisions Overlying Corneal Ring Segments: Case Series and Literature Review. Cornea 2011; 30:968-71. [DOI: 10.1097/ico.0b013e3182031ca0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Choi SW, Choae WS, Her J. Intrastromal Corneal Ring Segments (KeraRing®) Implantation for the Correction of Keratoconus. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2011. [DOI: 10.3341/jkos.2011.52.3.277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Sung Wook Choi
- Department of Ophthalmology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Woo Seok Choae
- Department of Ophthalmology, Masan Samsung Hospital, Sungkyunkwan University School of Medicine, Masan, Korea
| | - Jun Her
- Department of Ophthalmology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
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Madar J, Proust H, Matonti F, Conrath J, Ridings B, Hoffart L. [New therapeutic approach of keratoconus with intracorneal ring segments aided by femtosecond laser (Tecnolas Perfect Vision): indications, operating technique and results]. J Fr Ophtalmol 2010; 34:2-9. [PMID: 21112667 DOI: 10.1016/j.jfo.2010.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 09/20/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To assess the results of intracorneal ring segment implantation assisted by the Tecnolas Perfect Vision(®) femtosecond laser (Heidelberg, Germany). SETTINGS Retrospective observational study. METHODS The patients were operated on with the Tecnolas Perfect Vision(®) femtosecond laser. The following parameters were evaluated before and after surgery: uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal topography, wavefront analysis, and central corneal thickness. The Wilcoxon test was used for statistical analysis. RESULTS Seventeen eyes of 15 patients were included. The mean follow-up was 6.9±0.71 months. Significant improvement of UCVA and BCVA was observed in 82.35% (P=0.027) and 94.12% (P=0.003) of the eyes, respectively. The subjective refraction showed a significant decrease of the sphere from -10.29±5.54 to -6.5±5.03D (P=0.002). The subjective cylinder significantly decreased from 5.43±3.20 to 3.69±2.30D (P=0.026). The SAI also decreased significantly (P=0.011). CONCLUSION Femtosecond-assisted intracorneal ring segment implantation is an effective treatment for corneal ectasia. Further studies are needed to improve surgical parameters and outcomes.
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Affiliation(s)
- J Madar
- Service d'ophtalmologie, hôpital de la Timone, 264, rue Saint-Pierre, 13385 Marseille cedex 5, France.
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Kubaloglu A, Sari ES, Cinar Y, Cingu K, Koytak A, Coşkun E, Özertürk Y. Comparison of mechanical and femtosecond laser tunnel creation for intrastromal corneal ring segment implantation in keratoconus. J Cataract Refract Surg 2010; 36:1556-61. [DOI: 10.1016/j.jcrs.2010.04.028] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 04/01/2010] [Accepted: 04/02/2010] [Indexed: 10/19/2022]
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Modification and refinement of astigmatism in keratoconic eyes with intrastromal corneal ring segments. J Cataract Refract Surg 2010; 36:1562-72. [DOI: 10.1016/j.jcrs.2010.04.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 02/24/2010] [Accepted: 04/19/2010] [Indexed: 11/23/2022]
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Implantation of new intracorneal ring segments after segment explantation for unsuccessful outcomes in eyes with keratoconus. J Cataract Refract Surg 2010; 36:1303-10. [DOI: 10.1016/j.jcrs.2010.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 02/02/2010] [Accepted: 02/10/2010] [Indexed: 10/19/2022]
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Piñero DP, Alio JL. Intracorneal ring segments in ectatic corneal disease - a review. Clin Exp Ophthalmol 2010; 38:154-67. [DOI: 10.1111/j.1442-9071.2010.02197.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Piñero DP, Alió JL, El Kady B, Pascual I. Corneal aberrometric and refractive performance of 2 intrastromal corneal ring segment models in early and moderate ectatic disease. J Cataract Refract Surg 2010; 36:102-9. [DOI: 10.1016/j.jcrs.2009.07.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 07/16/2009] [Accepted: 07/22/2009] [Indexed: 11/27/2022]
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Sansanayudh W, Bahar I, Kumar NL, Shehadeh-Mashour R, Ritenour R, Singal N, Rootman DS. Intrastromal corneal ring segment SK implantation for moderate to severe keratoconus. J Cataract Refract Surg 2010; 36:110-3. [PMID: 20117713 DOI: 10.1016/j.jcrs.2009.07.040] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 07/10/2009] [Accepted: 07/12/2009] [Indexed: 11/15/2022]
Affiliation(s)
- Wiwan Sansanayudh
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Ontario, Canada.
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Ha CI, Choi SK, Lee DH, Kim JH. The Clinical Results of Intrastromal Corneal Ring Segment Implantation Using a Femtosecond Laser in Keratectasia. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2010. [DOI: 10.3341/jkos.2010.51.1.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Chang Il Ha
- Department of Ophthalmology, Ilsan Paik Hospital, Inje University College of Medicine, Ilsan, Korea
| | - Suk Kyue Choi
- Department of Ophthalmology, Ilsan Paik Hospital, Inje University College of Medicine, Ilsan, Korea
| | - Do Hyung Lee
- Department of Ophthalmology, Ilsan Paik Hospital, Inje University College of Medicine, Ilsan, Korea
| | - Jin Hyoung Kim
- Department of Ophthalmology, Ilsan Paik Hospital, Inje University College of Medicine, Ilsan, Korea
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Piñero DP, Alio JL, El Kady B, Coskunseven E, Morbelli H, Uceda-Montanes A, Maldonado MJ, Cuevas D, Pascual I. Refractive and aberrometric outcomes of intracorneal ring segments for keratoconus: mechanical versus femtosecond-assisted procedures. Ophthalmology 2009; 116:1675-87. [PMID: 19643498 DOI: 10.1016/j.ophtha.2009.05.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 05/11/2009] [Accepted: 05/12/2009] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE To compare visual, refractive, and corneal aberrometric outcomes in keratoconic eyes implanted with intracorneal ring segments (ICRS) implantation using either a mechanical or a femtosecond laser-assisted procedure. DESIGN Retrospective, consecutive case series. PARTICIPANTS A total of 146 consecutive eyes of 106 patients with the diagnosis of keratoconus (68 unilateral and 39 bilateral) were included. Two groups were created according to the surgical technique used for corneal tunnelization: Mechanical group (mechanical tunnelization, 63 eyes) and Femtosecond group (femtosecond laser-assisted tunnelization, 83 eyes). Intracorneal ring segments implantation was indicated because of the existence of reduced best spectacle-corrected visual acuity (BSCVA) or contact lens intolerance. METHODS Intracorneal ring segments implantations were performed by 6 surgeons following the same protocol except for the incision location. A total of 55 eyes were implanted with Intacs (Addition Technology, Inc, Fremont, CA) and 8 eyes were implanted with KeraRings (Mediphacos, Belo Horizonte, Brazil) in the Mechanical group, and 25 eyes were implanted with Intacs and 58 eyes were implanted with KeraRings in the Femtosecond group. Mean follow-up was 10.66+/-8.20 months, ranging from 1 month to 24 months. MAIN OUTCOME MEASURES Uncorrected visual acuity (UCVA), BSCVA, refraction, keratometry, and root mean square (RMS) for different kinds of corneal aberrations. RESULTS By reporting only for statistically significant changes, UCVA improved in both groups at 6 months (P< or =0.02) and BSCVA improved in the Femtosecond group (P<0.01). The refraction improved in both groups at 6 months (P< or =0.02). The cornea on average was flatter in both groups at 6 months (P<0.01). Root mean square astigmatism was reduced in the Femtosecond group (P = 0.03), but there was an increase in some higher-order aberrations (P = 0.03). Significant differences were found between the 2 groups for eyes implanted with Intacs for primary spherical aberration, coma, and other higher-order aberrations, favoring the Femtosecond group (P< or =0.01). A significant negative correlation was found between the preoperative corneal aberrations and the postoperative BSCVA in the Mechanical group (r>0.63, P< or =0.04). CONCLUSIONS Intracorneal ring segments implantation using both mechanical and femtosecond laser-assisted procedures provide similar visual and refractive outcomes. A more limited aberrometric correction is observed for eyes with mechanical implantation. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Kim HS, Lee TH, Lee KH. Intracorneal Ring Segment Implantation for the Management of Keratoconus: Short-Term Safety and Efficacy. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2009. [DOI: 10.3341/jkos.2009.50.10.1505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ertan A, Karacal H. Factors influencing flap and INTACS decentration after femtosecond laser application in normal and keratoconic eyes. J Refract Surg 2008; 24:797-801. [PMID: 18856233 DOI: 10.3928/1081597x-20081001-05] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare accuracy of LASIK flap and INTACS centration following femtosecond laser application in normal and keratoconic eyes. METHODS This is a retrospective case series comprising 133 eyes of 128 patients referred for refractive surgery. All eyes were divided into two groups according to preoperative diagnosis: group 1 (LASIK group) comprised 74 normal eyes of 72 patients undergoing LASIK with a femtosecond laser (IntraLase), and group 2 (INTACS group) consisted of 59 eyes of 39 patients with keratoconus for whom INTACS were implanted using a femtosecond laser (IntraLase). Decentration of the LASIK flap and INTACS was analyzed using Pentacam. RESULTS Temporal decentration was 612.56 +/- 384.24 microm (range: 30 to 2120 microm) in the LASIK group and 788.33 +/- 500.34 microm (range: 30 to 2450 microm) in the INTACS group. A statistically significant difference was noted between the groups in terms of decentration (P < .05). Regression analysis showed that the amount of decentration of the LASIK flap and INTACS correlated with the central corneal thickness in the LASIK group and preoperative sphere and cylinder in the INTACS group, respectively. CONCLUSIONS Decentration with the IntraLase occurred in most cases, especially in keratoconic eyes. The applanation performed for centralization during IntraLase application may flatten and shift the pupil center, and thus cause decentralization of the LASIK flap and INTACS. Central corneal thickness in the LASIK group and preoperative sphere and cylinder in the INTACS group proved to be statistically significant parameters associated with decentration.
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Ertan A, Kamburoğlu G. Intacs implantation using a femtosecond laser for management of keratoconus: Comparison of 306 cases in different stages. J Cataract Refract Surg 2008; 34:1521-6. [PMID: 18721713 DOI: 10.1016/j.jcrs.2008.05.028] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Accepted: 05/06/2008] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate the efficacy of intrastromal ring segment (Intacs, Addition Technology, Inc.) implantation and analyze outcomes according to different keratoconus stages. SETTING Kudret Eye Hospital, Ankara, Turkey. METHOD In this retrospective noncomparative case series, 306 keratoconic eyes of 255 patients who had Intacs segment implantation were reviewed. Patients were grouped according to the Amsler-Krumeich keratoconus classification (stage II, 155 eyes; stage III, 83 eyes; stage IV, 68 eyes). The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), central corneal curvature, spherical and cylindrical manifest refractions, and central corneal thickness were analyzed and compared according to keratoconus stage. RESULTS At a mean follow-up of 10.39 months +/- 5.04 (SD), the BCVA improved in 71.6% of eyes and the UCVA improved in 75.7% of eyes. The mean keratometry (K) decreased from 50.7 diopters (D) to 47.9 D (P<.05); the mean manifest spherical refraction, from -6.04 D to -3.09 D (P<.05); and the mean manifest cylindrical refraction, from -4.11 D to -3.82 D (P>.05). The changes in BCVA and manifest spherical and cylindrical refractions were not statistically different between the different keratoconus stages (P >.05). There was less change in UCVA and more improvement in the mean K value after Intacs treatment in stage IV than in the other stages (P<.05, analysis of variance). CONCLUSIONS Intacs treatment with a femtosecond laser was effective for management of keratoconus of all stages. Improvement in UCVA may be less in severe keratoconus than in moderate keratoconus.
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Affiliation(s)
- Aylin Ertan
- Kudret Eye Hospital, Kennedy Caddesi No. 71, Kavaklidere, Ankara, Turkey.
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Coskunseven E, Kymionis GD, Tsiklis NS, Atun S, Arslan E, Jankov MR, Pallikaris IG. One-year results of intrastromal corneal ring segment implantation (KeraRing) using femtosecond laser in patients with keratoconus. Am J Ophthalmol 2008; 145:775-9. [PMID: 18291344 DOI: 10.1016/j.ajo.2007.12.022] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 12/12/2007] [Accepted: 12/14/2007] [Indexed: 11/26/2022]
Abstract
PURPOSE To report the results of intrastromal corneal ring segment [ICRS] (KeraRing; Mediphacos, Belo Horizonte, Brazil) implantation using a femtosecond laser (IntraLase Corp, Irvine, California, USA) in keratoconic patients. DESIGN Retrospective, noncomparative, interventional study. METHODS Thirty-two keratoconic patients (50 eyes) who underwent ICRS insertion using a femtosecond laser for channel creation and completed at least one year of follow-up were included in this study. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, topographic findings, and adverse events were assessed. RESULTS No intraoperative complications were demonstrated in this series of patients. At the first postoperative day, segment migration to the incision site was seen in three eyes (6%; early postoperative complication). To avoid melting, we repositioned the migrated segment away from the incision site. Serious second migration was not seen and we did not need to reposition any segment again. At the last postoperative examination, there was a statistically significant reduction in the spherical equivalent refractive error compared with that observed at the examination before implantation (mean +/- standard deviation, -5.62 +/- 4.15 diopters [D; range, -23.62 to 0.50 D] to -2.49 +/- 2.68 D [range, -11.12 to 3.5 D]; P < .001). The UCVA before implantation was 20/40 or worse in 47 eyes (94%; range, counting fingers to 20/30), whereas at the last follow-up examination, 14 (28%) of 50 eyes had a UCVA of 20/40 or better (range, counting fingers to 20/25). Nine eyes (18%) maintained the preimplantation BSCVA, whereas 39 eyes (68%) experienced a BSCVA gain of one to four lines at the last follow-up examination. Only in two eyes (4%; two patients) with advanced keratoconus (stage III) was there a decrease of up to two lines. Despite this deterioration in BSCVA, the patients did not want to remove the ICRSs, because there was an increase of UCVA. No late postoperative complications were observed during the follow-up period. CONCLUSIONS ICRS (KeraRing) implantation using femtosecond laser for tunnel creation is a minimally invasive procedure for improving visual acuity (both UCVA and BSCVA) in keratoconic patients.
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Kymionis GD, Bouzoukis DI, Haft P, Siganos CS, Yoo S. Intrastromal corneal ring segments for the treatment of irregular astigmatism. EXPERT REVIEW OF OPHTHALMOLOGY 2008. [DOI: 10.1586/17469899.3.1.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Emre S, Doganay S, Yologlu S. Evaluation of anterior segment parameters in keratoconic eyes measured with the Pentacam system. J Cataract Refract Surg 2007; 33:1708-12. [PMID: 17889764 DOI: 10.1016/j.jcrs.2007.06.020] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Accepted: 06/08/2007] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the alteration in anterior chamber parameters with the progression of keratoconus using a rotating Scheimpflug camera. SETTING Inonu University, Turgut Ozal Medical Center, Ophthalmology Department, Malatya, Turkey. METHODS Two hundred sixteen eyes of 123 patients diagnosed with keratoconus and 224 eyes of 112 normal subjects were evaluated with a Pentacam Scheimpflug camera (Oculus Inc.). Keratoconic eyes were divided into 3 groups according to mean keratometer (K) readings: mild (K = less than 47.0 diopters [D]), moderate (K = 47.0 to 52.0 D), and severe (K = 52.0 D or higher). The following parameters were obtained: thinnest corneal thickness (TCT), anterior chamber depth (ACD), corneal volume (CV), anterior chamber angle (ACA), and anterior chamber volume (ACV). RESULTS One hundred twenty-nine eyes had mild keratoconus, 59 had moderate keratoconus, and 35 had severe keratoconus. There were no statistically significant differences between the keratoconus group and control group in age, sex, or eye distribution (P>.05). With the progression of the disease, TCT and ACD were statistically different between all groups (P<.05). There were statistically significant differences in ACA and CV measurements between the mild keratoconus and severe keratoconus groups (P<.05). Also, CV readings were significantly different between the control group and all keratoconus groups (P<.05), although there was no significant difference in ACA measurements (P>.05). Despite a progressive increase in the ACV with disease progression, the differences between groups were not statistically significant (P>.05) except between the severe keratoconus group and the control group (P<.05). CONCLUSION Anterior segment parameters of the eye showed significant alterations with the progression of keratoconus.
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Affiliation(s)
- Sinan Emre
- Department of Ophthalmology, School of Medicine, Inonu University, Malatya, Turkey.
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Abstract
PURPOSE To evaluate the efficacy of intracorneal ring segments to treat keratoconus and post-laser in situ keratomileusis (LASIK) keratectasia implanted by using either mechanical dissection or a femtosecond laser. METHODS Thirty-three eyes of 29 patients had intracorneal ring segments implanted by using mechanical dissection (17 eyes) or a femtosecond laser (16 eyes). Mean follow-up was 10.3 months. Parameters assessed before and after surgery included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent (MRSE), refractive cylinder (RC), best contact lens-corrected visual acuity (BCLVA), and contact lens tolerance. RESULTS Statistically significant changes occurred for all parameters when we analyzed all 33 eyes as 1 group. Mean UCVA LogMar values improved from 1.0 +/- 0.3 (20/200) to 0.6 +/- 0.4 (20/80) (P < 0.0005). Mean BSCVA changed from 0.3 +/- 0.2 (20/40) to 0.2 +/- 0.2 (20/30) (10%; P < 0.05), and MRSE from -9 +/- 4 to -7 +/- 4 D (P < 0.05; 20%). There was a decrease of 0.5 D or more of RC in 62% of eyes. BCLVA improved from 0.2 +/- 0.2 (20/30) to 0.1 +/- 0.1 (20/25) after surgery (P < 0.02). Contact lens tolerance improved in 81% of eyes. There was no statistically significant difference in outcomes between mechanical dissection and femtosecond laser-assisted techniques. However, although statistical power was adequate to detect changes in clinical parameters as a result of surgery, it was not sufficient to conclusively show such differences between surgical techniques. CONCLUSIONS For mild to moderate cases of keratoconus and post-LASIK keratectasia, the use of a femtosecond laser for Intacs channel creation seems as effective as mechanical dissection. Future studies are warranted to further evaluate channel creation by a femtosecond laser.
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Ertan A, Colin J. Intracorneal rings for keratoconus and keratectasia. J Cataract Refract Surg 2007; 33:1303-14. [PMID: 17586391 DOI: 10.1016/j.jcrs.2007.02.048] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Accepted: 02/15/2007] [Indexed: 10/23/2022]
Abstract
Intrastromal corneal ring segments were designed to achieve refractive adjustment by flattening the cornea. Recently, they have been used to reshape keratoconic corneas to improve uncorrected visual acuity, best corrected visual acuity, and contact lens tolerance and to delay or prevent the need for keratoplasty. Intracorneal ring segments have several distinct and important advantages. New thicknesses and different ring sizes and the use of femtosecond lasers to dissect channels inside the cornea will likely improve the surgical outcomes. This article reviews the latest data published or presented at meetings on the correction of keratoconus and keratectasia by intracorneal ring segments.
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Affiliation(s)
- Aylin Ertan
- Kudret Eye Hospital, Ankara, Turkey, and the Bordeaux University, Bordeaux, France.
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Abstract
PURPOSE OF REVIEW The use of Intacs as a therapeutic modality in contact lens intolerant patients with mild to moderate keratoconus is increasingly gaining acceptance in the ophthalmic community. RECENT FINDINGS During the past year we have gleaned significant new information about patients who are appropriate candidates, the location and relative placement of segment sizes and long-term safety and stability after Intacs placement. Another new and exciting development which will make this procedure safer and more commonly acceptable is the use of the femtosecond laser to create the channels to insert the Intacs, which has been described for the first time this year. This technology allows for accurate depth of inserting, improved outcomes and less complications due to superficial placement. New reports about Intacs revision surgery also allows us to retreat many patients who would otherwise have been considered surgical failures. SUMMARY The new advances described this past year will improve outcomes and ultimately contribute to an increase in the amount of physicians performing this procedure and the number of patients requesting it.
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Affiliation(s)
- Yaron S Rabinowitz
- Ophthalmology Research, Cornea Genetic Eye Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
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Ertan A, Kamburoğlu G, Akgün U. Comparison of outcomes of 2 channel sizes for intrastromal ring segment implantation with a femtosecond laser in eyes with keratoconus. J Cataract Refract Surg 2007; 33:648-53. [PMID: 17397738 DOI: 10.1016/j.jcrs.2007.01.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 01/12/2007] [Indexed: 12/01/2022]
Abstract
PURPOSE To compare the outcomes of 2 channel sizes for intrastromal ring segment (Intacs, Addition Technology, Inc.) implantation using a femtosecond laser in eyes with keratoconus. SETTING Kudret Eye Hospital, Ankara, Turkey. METHODS A retrospective outpatient study included 159 consecutive keratoconic eyes of 103 patients. Patients were classified into 2 groups according to channel dissection size: wide (6.7 mm x 8.2 mm) and narrow (6.6 mm x 7.6 mm). Dissections were created with an IntraLase femtosecond laser (IntraLase Corp.). The 2 groups were compared according to uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive error (manifest sphere, manifest cylinder, and manifest refractive spherical equivalent), mean K-value, and complications within 6 months postoperatively. RESULTS The wide-channel group comprised 97 eyes of 65 patients (37 men, 28 women) with a mean age of 27.64 years +/- 8.61 (SD). The narrow-channel group comprised 62 eyes of 38 patients (23 men, 15 women) with a mean age of 26.62 +/- 6.13 years. At 6 months, the UCVA and BCVA had significantly improved in 63.9% and 70.1% of eyes, respectively, in the wide-channel group and in 72.5% and 75.8% of eyes, respectively, in the narrow-channel group. The change in mean BCVA and change in mean UCVA in both groups were not statistically significant (P<.05, independent samples t test). There was no between-group difference in the improvement in manifest spherical refraction, cylindrical refraction, manifest refractive spherical equivalent, or mean K-readings (P<.05, independent samples t test). Epithelial plug, yellow-white deposits, tunnel haze around segments, and upward movement of the inferior segment without extrusion were observed more frequently in the narrow-channel group than in the wide-channel group. CONCLUSIONS The refractive outcomes of wide channels and narrow channels for Intacs treatment in eyes with keratoconus were similar 6 months postoperatively. The narrow-channel group had a higher rate of mild to moderate complications than the wide-channel group.
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Tomalla M, Cagnolati W. Modern treatment options for the therapy of keratoconus. Cont Lens Anterior Eye 2007; 30:61-6. [PMID: 17207654 DOI: 10.1016/j.clae.2006.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 12/04/2006] [Accepted: 12/05/2006] [Indexed: 11/26/2022]
Abstract
The following case report describes the implantation of intrastromal corneal ring segments (ICRS) and the postoperative contact lens treatment in a 42-year-old patient with bilateral advanced keratoconus. The patient had a preoperative contact lens intolerance. After femtosecond laser assisted surgery and the implantation of ICRS new custom mini-scleral contact lenses were fitted. The postoperative subjective and objective contact lens tolerance was excellent.
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Affiliation(s)
- Mark Tomalla
- EJK Niederrhein, Klinik für refraktive und Ophthalmochirurgie, Fahrner Str. 133, D-47169 Duisburg, Germany
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Ertan A, Kamburoğlu G. Analysis of centration of Intacs segments implanted with a femtosecond laser. J Cataract Refract Surg 2007; 33:484-7. [PMID: 17321400 DOI: 10.1016/j.jcrs.2006.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Accepted: 11/27/2006] [Indexed: 10/23/2022]
Abstract
PURPOSE To analyze the centration of intrastromal ring segments (Intacs, Addition Technology, Inc.) implanted using a femtosecond laser in eyes with keratoconus. SETTING Kudret Eye Hospital, Ankara, Turkey. METHODS In a retrospective noncomparative case series, the distance of deviation of the intrastromal ring segment from the pupillary center was evaluated in 59 eyes of 39 keratoconic patients after tunnel creation with a femtosecond laser. The distance of deviation of segments from the pupillary edge and direction of decentration were analyzed using the anterior segment analyzer of the Pentacam Scheimpflug photographic camera (Oculus Opticgerate GmbH). RESULTS Intacs were successfully implanted in all eyes. The mean horizontal deviation was 788.33 microm +/- 500.34 (SD) (range 30 to 2450 microm), and there was a temporal displacement in all eyes. The mean vertical deviation was 370.83 +/- 343.17 microm (range 0 to 1690 microm), and there was an inferior displacement in 28.81% of eyes and superior displacement in 66.10% of eyes. There was no vertical displacement in 3 eyes (5.08%). CONCLUSION During applanation for Intacs correction by a femtosecond laser, the cornea and pupil are not in their natural position, which leads to decentration and misalignment of the segments.
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Affiliation(s)
- Aylin Ertan
- Kudret Göz Hastanesi, Kennedy Caddesi No:71, Kavaklidere, Ankara, Turkey.
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Chan CCK, Wachler BSB. Reduced Best Spectacle-corrected Visual Acuity from Inserting a Thicker Intacs Above and Thinner Intacs Below in Keratoconus. J Refract Surg 2007; 23:93-5. [PMID: 17269250 DOI: 10.3928/1081-597x-20070101-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To report a case of decreased best spectacle-corrected visual acuity (BSCVA) 2 months after Intacs implantation. METHODS A 33-year-old woman with keratoconus and contact lens intolerance underwent Intacs surgery in the left eye at another institution. Two segments were used--a thinner one (0.25 mm) below the cone and a thicker one (0.35 mm) above the cone. RESULTS Two months postoperatively, the patient presented to our practice with BSCVA reduced from 20/20 to 20/30. The superior Intacs segment was explanted, the inferior segment was exchanged for a thicker one (0.35 mm), and collagen cross-linking with riboflavin treatment was performed. This resulted in visual, topographic, and refractive improvement with BSCVA returning to 20/20. CONCLUSIONS Single inferior segment Intacs may be more appropriate for paracentral and peripheral cones. Collagen cross-linking may help cause further flattening. Using asymmetrical segments, with the thicker segment above the cone, may increase distortions and result in loss of BSCVA.
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Affiliation(s)
- Colin C K Chan
- Boxer Wachler Vision Institute, Beverly Hills, Calif, USA
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Chan CCK, Sharma M, Wachler BSB. Effect of inferior-segment Intacs with and without C3-R on keratoconus. J Cataract Refract Surg 2007; 33:75-80. [PMID: 17189797 DOI: 10.1016/j.jcrs.2006.09.012] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Accepted: 09/25/2006] [Indexed: 11/19/2022]
Abstract
PURPOSE To determine whether corneal collagen cross-linking with riboflavin (C3-R) augments the effect of inferior-segment Intacs (Addition Technology) in the treatment of keratoconus. SETTING Private practice, Beverly Hills, California, USA. METHODS A retrospective nonrandomized comparative case series comprised 12 eyes of 9 patients who had inferior-segment Intacs placement without C3-R (Intacs-only group) and 13 eyes of 12 patients who had inferior-segment Intacs placement combined with C3-R (Intacs with C3-R group). The 2 groups were matched preoperatively. All patients had inferior-segment Intacs placed with the incision in the steep axis of manifest refraction. Corneal collagen cross-linking with riboflavin was performed after the Intacs segments were inserted. Outcome measures were topographic keratometry values and the lower-upper (L-U) ratio, which is a topographic measure of the degree of keratoconus. Preoperative data were compared to results 1 day postoperatively and measurements at the last postoperative visit. RESULTS The Intacs with C3-R group had a significantly greater reduction in cylinder than the Intacs-only group (P<.05). Steep and average keratometry were reduced significantly more in the Intacs with C3-R group (P<.05). There was a greater reduction in L-U ratio in the Intacs with C3-R group (P<.05). CONCLUSION The addition of C3-R to the Intacs procedure resulted in greater keratoconus improvements than Intacs insertion alone.
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Ertan A, Kamburoğlu G, Bahadir M. Intacs insertion with the femtosecond laser for the management of keratoconus. J Cataract Refract Surg 2006; 32:2039-42. [PMID: 17137980 DOI: 10.1016/j.jcrs.2006.08.032] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 08/18/2006] [Indexed: 11/24/2022]
Abstract
PURPOSE To assess the outcomes of intrastromal ring segment (Intacs, Addition Technology) implantation for keratoconus using the femtosecond laser. SETTING Kudret Eye Hospital, Ankara, Turkey. METHODS In a retrospective noncomparative case series, 118 eyes of 69 patients with keratoconus who had Intacs segments implanted with the femtosecond laser were evaluated. Preoperative and postoperative evaluations included slitlamp examination, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and mean keratometry values measured with the Pentacam Scheimpflug camera (Oculus Opticgerate GmbH). All parameters were assessed preoperatively and 1 year after Intacs implantation. RESULTS Intacs were successfully implanted in all eyes. At the end of the first postoperative year, 81.3% of eyes had improved UCVA and 73.7% had improved BCVA. The mean keratometry decreased from 51.56 diopters (D) to 47.66 D, and the mean refractive spherical equivalent decreased from -7.57 D to -3.72 D. CONCLUSIONS Intacs implantation with the femtosecond laser was safe and effective for the treatment of keratoconus. All parameters had improved by the 1-year follow-up.
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Pesudovs K, Coster DJ. Penetrating Keratoplasty for Keratoconus: The Nexus Between Corneal Wavefront Aberrations and Visual Performance. J Refract Surg 2006; 22:926-31. [PMID: 17124891 DOI: 10.3928/1081-597x-20061101-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the visual and optical performance after penetrating keratoplasty (PK) for keratoconus to normal patients and to examine the relationship between corneal wavefront aberrations and visual performance in patients with PK. METHODS Visual performance testing, with optimal refractive correction, included low contrast visual acuity (LCVA) and Pelli-Robson contrast sensitivity with and without glare, and high contrast visual acuity. Corneal first surface wavefront aberrations were calculated from EyeSys topography data using VOL-Pro software v7.00 for a 4.0-mm pupil as a 10th order Zernike expansion and converted into single value metrics. Normal patients were compared to patients with PK using analysis of variance, and linear regression was used to compare wavefront aberration metrics to visual performance. RESULTS Patients with PK (n=14, age 41.6 +/- 7.0 years) and normal patients (n=14, age 36.7-9.0 years) were of similar age (F(1, 26) = 2.54, P = .12). Normal patients saw significantly better on all visual performance measures and had better optical performance for total higher order root-mean-square corneal wavefront aberration (mean-SD): PK, 0.67 +/- 0.41 microm; normal, 0.09 +/- 0.02 microm (F(1,26) = 28.41, P < .001) and across all Zernike orders and modes. Wavefront aberrations in PK eyes were dominated by trefoil 0.35 +/- 0.27 microm, coma 0.47 +/- 0.37 microm, spherical aberration 0.17 +/- 0.10 microm, and tetrafoil 0.12 +/- 0.07 microm. The relationships between corneal wavefront aberration and visual performance metrics were strongest for LCVA = 0.30-0.98 Pupil fraction for wavefront (tessellation) -0.04 Half width at half height, R2=0.75. CONCLUSIONS In this series, patients with PK had poorer visual performance compared to normal patients, which is due to increased corneal wavefront aberrations. Outcomes research in corneal transplantation should include measurement of wavefront aberrations and visual performance in the contrast domain.
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Affiliation(s)
- Konrad Pesudovs
- NH&MRC Centre for Clinical Eye Research, Department of Ophthalmology, Flinders Medical Centre and Flinders University, Bedford Park, South Australia, Australia.
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Rabinowitz YS, Li X, Ignacio TS, Maguen E. INTACS Inserts Using the Femtosecond Laser Compared to the Mechanical Spreader in the Treatment of Keratoconus. J Refract Surg 2006; 22:764-71. [PMID: 17061713 DOI: 10.3928/1081-597x-20061001-06] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine the efficacy of INTACS insertion using a femtosecond laser in the treatment of keratoconus and to compare it to the technique using a mechanical spreader. METHODS INTACS were inserted in 10 eyes using the mechanical spreader to create the channels and subsequently on another 20 eyes using the femtosecond laser. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), manifest refraction, and corneal topography were measured prior to surgery, at 6 months (femtosecond group), and 1 year (mechanical group). Pre- and postoperative data were analyzed to determine changes in the above parameters. RESULTS Both groups showed significant reduction in average keratometry (K), spherical equivalent refraction, BSCVA, UCVA, surface regularity index (SRI), and surface asymmetry index (SAI). The laser group performed better in all parameters except change in SRI. Results of the laser versus the mechanical spreader were as follows: reduction in spherical equivalent refraction (3.98 vs 2.96), change in average K (2.91 vs 2.52), improvement in UCVA (4.13 vs 3.63), improvement in BSCVA (3.92 vs 1.63), change in SRI (0.37 vs 0.64), and change in SAI (1.00 vs 0.70). Statistical analysis, however, did not reveal any statistically significant differences between the two groups for any single parameter studied. The biggest improvement in the laser group versus the mechanical group was BSCVA (P=.09). Overall success, defined as contact lens or spectacles tolerance, was 85% in the laser group and 70% in the mechanical group. CONCLUSIONS Inserting INTACS using the femtosecond laser to create the channels is as effective as using the mechanical spreader.
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Affiliation(s)
- Yaron S Rabinowitz
- Cornea Genetic Eye Institute, Cedars-Sinai Medical Center, 444 S San Vicente Blvd, #1102, Los Angeles, CA 90048, USA.
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