Klinische und histologische Studien zu den intrastromalen kornealen Ringsegmenten (ICRS®, Intacs®)

 

 Buy Article Permissions and Reprints

Zusammenfassung

Intrastromale korneale Ringsegmente (ICRS®, Intacs®) sind Hornhautimplantate aus PMMA mit einer Bogenlänge von 150° zur Korrektur einer niedrigen Myopie bis etwa - 4 D. Dieses additive und damit potenziell reversible chirurgische Verfahren wurde in den letzten Jahren zur klinischen Reife geführt. Neben der Entwicklung der Methodik und den Ergebnissen der amerikanischen (US-FDA-)Studien wird vor allem über die europäischen Erfahrungen mit dieser Technik berichtet. Erstmals werden Langzeitergebnisse (aus der Landesaugenklinik Salzburg) mit einer Nachbeobachtung bis zu 5 Jahren präsentiert. Die biomikroskopisch sichtbaren Veränderungen der Hornhaut nach Intacs®-Implantation wurden an einer Serie von Patienten mittels konfokaler Mikroskopie untersucht. Einige Wochen und Monate nach der Implantation der PMMA-Segmente kommt es zum Auftreten von morphologischen Veränderungen in Form so genannter „Lamellar Channel Deposits” um die Implantate. Neue histologische Untersuchungen an Versuchstieren ergaben, dass es sich bei diesem Material um intrazelluläre Fette (Cholesterol-Estern, Triglyzeriden und unverestertes Cholesterol) handelt. Zu den neuesten Entwicklungen dieser Technik zählen kürzere Segmente zur Korrektur von myopem Astigmatismus sowie stabförmige, kurze radiäre Implantate (intrastromale korneale Segmente, ICS®) zur Hyperopiekorrektur. In den letzten Jahren wurde ebenfalls versucht, Intacs® bei Keratokonus und Keratektasie nach LASIK einzusetzen. Diese noch sehr frühen Resultate geben Hoffnung, dass diese Technik in ausgewählten Fällen von Keratokonus zu einer Verbesserung der Hornhautgeometrie führen kann. Auch der Einsatz von Intacs® zur Korrektur einer Restmyopie nach Regression oder unterkorrigierter LASIK (mit zu dünner Hornhaut für eine weitere Laserbehandlung) erscheint viel versprechend. Obwohl die klinischen Daten der Intacs®-Implantation sowohl hinsichtlich der Sicherheit als auch der Effektivität jenen von PRK und LASIK entsprechen, hat sich die Intacs®-Technologie bei refraktiven Chirurgen und Patienten bisher noch nicht in großem Ausmaß durchsetzen können. Ob Intacs® - trotz ihrer unbestreitbaren Vorzüge - ihre Stellung in der refraktiven Routinepraxis halten und ausbauen werden können oder als „Nischenprodukt” für Keratokonus, Keratektasien oder Regressionen nach LASIK übrig bleiben, wird erst die Zukunft zeigen.

Abstract

Intrastromal corneal ring segments (ICRS®, Intacs®) are corneal inlays made of PMMA with an arc length of 150° for the correction of low to moderate myopia. This additive and potentially reversible method has recently been developed to clinical usefulness during the last few years. Besides the historical development und the results of the US FDA studies, we focus on the results of the European experience with this technique. For the first time, long-time follow-up results (5 years from a single surgical center) are presented. Morphological changes after implantation of Intacs® were investigated in a series of patients by confocal microscopy. Weeks and months after implantation „lamellar channel deposits” regularly appear around the segments. This material consists of intracellular lipids (cholesterol ester, triglyceride and unesterified cholesterol), as we could show in new histological studies on rabbit eyes. New developments of this technique include short arc length segments (130°) for the correction of myopia concurrent with astigmatism and radially placed corneal inlays (Intrastromal Corneal Segments, ICS®) for the correction of hyperopia. In recent years, Intacs® have also been implanted in eyes with keratoconus and keratectasia after LASIK. These early results seem to indicate that in certain cases of early keratoconus, these implants can indeed improve corneal geometry and vision. Even in cases of regression or undercorrection after LASIK (with thin corneas), Intacs® seem to give promising results in selected cases. Although Intacs® do give comparable results regarding both safety and efficacy when compared with PRK and LASIK, this technology has not yet been widely accepted among refractive surgeons. Whether Intacs® will play a greater role in routine refractive surgery in the future or will just remain a special device for the correction of keratectasia, keratoconus or regression after LASIK cannot yet be decided with certainty.

Literatur

• 1 Altmann J, Grabner G, Husinsky W, Mitterer S, Baumgartner I, Skorpik F. et al . Corneal lathing using the excimer laser and a computer-controlled positioning system: Part I-Lathing of epikeratoplasty lenticules.  Refract Corneal Surg. 1991;  7 (5) 377-384
  PubMedGoogle Scholar
• 2 Asbell P A, Uçakhan O O, Abbott R L, Assil K A, Burris T E, Durrie D S. et al . Intrastromal corneal ring segments: reversibility of refractive effect.  J Refract Surg. 2001;  17 25-31
  PubMedGoogle Scholar
• 3 Asbell P A, Ucakhan O O. Long-term follow-up of Intacs from a single center.  J Cataract Refract Surg. 2001;  27 (9) 1456-1468
  CrossrefPubMedGoogle Scholar
• 4 Asbell P A, Ucakhan O O, Odrich M. Photorefractive keratectomy after intrastromal corneal ring segment explantation.  Am J Ophthalmol. 1999;  128 (6) 755-756
  CrossrefPubMedGoogle Scholar
• 5 Assil K, Barrett A, Fouraker B. One year results of the intrastromal corneal ring in nonfunctional human eyes.  Arch Ophthalmol. 1995;  113 159-167
  PubMedGoogle Scholar
• 6 Assil K, Quantock A, Barrett A. Corneal iron lines associated with the intrastromal corneal ring.  Am J Ophthalmol. 1993;  116 350-356
  PubMedGoogle Scholar
• 7 Azar R G, Holdbrook M J, Lemp M, Edelhauser H F,. KeraVision Study Group . Two-year corneal endothelial cell assessment following INTACS implantation.  J Refract Surg. 2001;  17 (5) 542-548
  PubMedGoogle Scholar
• 8 Baikoff G, Maia N, Poulhalec D, Fontaine A, Giusiano B. Diurnal variations in keratometry and refraction with intracorneal ring segments.  J Cataract Refract Surg. 1999;  25 (8) 1056-1061
  CrossrefPubMedGoogle Scholar
• 9 Barraquer J I. Queratoplastia refractiva, estudios e informaciones.  Oftalmologicas. 1949;  2 10-30
  PubMedGoogle Scholar
• 10 Barraquer J I. Modofication de la refracion por medio de inclusiones intracorneales.  Arc Soc Am Oftalmol Optom. 1963;  4 229-262
  PubMedGoogle Scholar
• 11 Barraquer J I. Modification of refraction by means of intracorneal inclusions.  Int Ophthalmol Clin.. 1966;  6 (1) 53-78
  PubMedGoogle Scholar
• 12 Barraquer J I. Keratophakia.  Trans Ophthalmol Soc U K. 1972;  92 499-516
  PubMedGoogle Scholar
• 13 Biowski R, Homolka P, Barisani-Asenbauer T, Baumgartner I, Husinsky W, Kaminski S. et al . Corneal lathing using the excimer laser and a computer-controlled positioning system.  J Refract Surg. 2000;  16 (1) 23-31
  PubMedGoogle Scholar
• 14 Bisantis C, Bisantis F. Intrastromal segmental perioptic implants for high myopia.  Invest Ophthalmol Vis Sci. 1995;  36 (suppl) 5988
  PubMedGoogle Scholar
• 15 Blavatskaya E D. Intralamellar homoplasty for the purpose of relaxation of refraction of the eye.  Arch Soc Ophthalmol Optom. 1968;  6 311-325 ,  (übersetzt aus Oftalmol Zh 1966; 7: 530 - 537)
  PubMedGoogle Scholar
• 16 Burris T E, Ayer C T, Evensen D A, Davenport J M. Effects of intrastromal corneal ring size and thickness on corneal flattening in human eyes.  J Refract Corneal Surg. 1991;  7 46-50
  PubMedGoogle Scholar
• 17 Burris T E, Baker P C, Ayer C T, Loomas B E, Mathis M L, Silvestrini T A. Flattening of central corneal curvature with intrastromal corneal rings of increasing thickness: An eye-bank study.  J Cataract Refract Surg. 1993;  19 (suppl) 182-187
  CrossrefPubMedGoogle Scholar
• 18 Cahill M, Condon P, O'Keefe M. Long-term outcome of epikeratophakia.  J Cataract Refract Surg. 1999;  25 (4) 500-507
  CrossrefPubMedGoogle Scholar
• 19 Chan S M, Khan H N. Reversibility and exchangeability of intrastromal corneal ring segments.  J Cataract Refract Surg. 2002;  28 (4) 676-681
  CrossrefPubMedGoogle Scholar
• 20 Choyce D P. The present status of intra-cameral and intra-corneal implants.  Can J Ophthalmol. 1968;  3 (4) 295-311
  PubMedGoogle Scholar
• 21 Choyce D P. The correction of refractive errors with polysulfone corneal inlays. A new frontier to be explored?.  Trans Ophthalmol Soc U K. 1985;  104 (Pt 3) 332-342
  PubMedGoogle Scholar
• 22 Cochener B, Le Floch G, Colin J. Intra-corneal rings for the correction of weak myopias.  J Fr Ophtalmol. 1998;  21 (3) 191-208
  PubMedGoogle Scholar
• 23 Colin J, Cochener B, Savary G, Malet F, Holmes-Higgin D. INTACS inserts for treating keratoconus: One-year results.  Ophthalmology. 2001;  108 (8) 1409-1414
  CrossrefPubMedGoogle Scholar
• 24 Colin J, Cochener B, Savary G, Malet F. Correcting keratoconus with intracorneal rings.  J Cataract Refract Surg. 2000;  26 (8) 1117-1122
  CrossrefPubMedGoogle Scholar
• 25 Davis E A, Hardten D R, Lindstrom R L. Laser in situ keratomileusis after intracorneal rings. Report of 5 cases.  J Cataract Refract Surg. 2000;  26 (12) 1733-1741
  CrossrefPubMedGoogle Scholar
• 26 D'Hermies F, Hartmann C, von Ey F, Holzkamper C, Renard G, Pouliquen Y. Biocompatibility of a refractive intracorneal PMMA ring.  Fortschr Ophthalmol. 1991;  88 790-793
  PubMedGoogle Scholar
• 27 Durrie D S, Vande Garde T L. Intacs After Laser in situ Keratomileusis: A Preliminary Report.  J Refract Surg. 2000;  16 (suppl) S236-S238
  PubMedGoogle Scholar
• 28 Ferrrara P. Técnica cirúrgica para correção de miopia. Anel corneano intra-estromal.  Revista Brasileira de oftalmologia. 1995;  54 (8) 19-30
  PubMedGoogle Scholar
• 29 Fink A M, Gore C, Rosen E S. Corneal changes associated with intrastromal corneal ring segments.  Arch Ophthalmol. 1999;  117 (2) 282
  PubMedGoogle Scholar
• 30 Fleming J F, Reynolds A E, Kilmer L, Burries T E, Abbott R L, Schanzlin D J. The intrastromal corneal ring: Two cases in rabbits.  J Refract Surg. 1987;  3 227-232
  PubMedGoogle Scholar
• 31 Fleming J, Wan W, Schanzlin D. The theory of corneal curvature change with the intrastromal ring.  CLAO J. 1989;  15 146-150
  PubMedGoogle Scholar
• 32 Fleming J F, Lovisolo C F. Intrastromal corneal ring segments in a patient with previous laser in situ keratomileusis.  J Refract Surg. 2000;  16 (3) 365-367
  PubMedGoogle Scholar
• 33 Goosey J D, Prager T C, Goosey C B, Martin D I. One year follow-up of epikeratoplasty for myopia.  J Cataract Refract Surg. 1990;  16 (1) 21-30
  PubMedGoogle Scholar
• 34 Gomez L, Chayet A. Laser in situ keratomileusis results after intrastromal corneal ring segments (Intacs).  Ophthalmology. 2001;  108 (10) 1738-1743
  CrossrefPubMedGoogle Scholar
• 35 Görges H W, Höh H, Rehfeldt K. Intrakorneale Ringsegmente zur Myopiekorrektur. Ergebnisse der Kleinschnitttechnik.  Ophthalmologe. 2001;  98 (7) 617-622
  CrossrefPubMedGoogle Scholar
• 36 Grabner G. Complications of epikeratophakia.  J Refract Surg. 1988;  4 96-104
  PubMedGoogle Scholar
• 37 Grabner G. Komplikationen der Epikeratophakie zur Korrektur von Aphakie, Myopie, Hyperopie und Keratoconus.  Fortschr Ophthalmol. 1991;  88 4-11
  PubMedGoogle Scholar
• 38 Grabner G, Ruckhofer J, Tratter C, Alzner E. Der Intrastromale Corneale Ring (KeraVision® Ring, ICR®, ICRS®). Eine moderne Methode zur Korrektur der geringen Myopie.  Wien Med Wochenschr. 1997;  147 309-321
  PubMedGoogle Scholar
• 39 Güell J L. New hope for high myopes: Intacs inserts after LASIK. Intacs inserts: Expanding the horizons of refractive technology. Chateney-Malabry, France; KeraVision Europe 2001: 6-8
  Google Scholar
• 40 Hartmann C, Rieck P W, Holzkamper C, Pouliquen Y, Renard G. The intrastromal corneal ring in clinical refractive surgery: reference to results in rabbit eyes.  Graefes Arch Clin Exp Ophthalmol. 2000;  238 (6) 465-471
  CrossrefPubMedGoogle Scholar
• 41 Hartmann C, Pharmakakis N, von Ey F. Intrastromale Implantation eines justierbaren Kunststoffringes zur Hornhautrefraktionsänderung. In: Freyler H, Skorpik C, Grasl M (Hrsg) 3. Kongress der Deutschen Gesellschaft für Intraokularlinsen-Implantation. Wien, New York; Springer-Verlag 1989: 465-475
  Google Scholar
• 42 Holmes-Higgin D K, Burris T E. Corneal surface topography and associated visual performance with INTACS for myopia: Phase III clinical trial results.  Ophthalmology. 2000;  107 (11) 2061-2071
  CrossrefPubMedGoogle Scholar
• 43 Holmes-Higgin D K, Baker P C, Burris T E, Silvestrini T A. Characterization of the aspheric corneal surface with intrastromal corneal ring segments.  J Refract Surg. 1999;  15 (5) 520-528
  PubMedGoogle Scholar
• 44 Holmes-Higgin D K, Burris T E, Asbell P A, Durrie D S, Schanzlin D J. Topographic predicted corneal acuity with intrastromal corneal ring segments.  J Refract Surg. 1999;  15 (3) 324-330
  PubMedGoogle Scholar
• 45 Höh H, Rehfeldt K, Reiss G. Myopiekorrektur mit dem intrakornealen Ring.  Ophthalmologe. 1999;  96 717-723
  CrossrefPubMedGoogle Scholar
• 46 Höh H, Rehfeldt K, Görges W. Der intrakorneale Ring zur Myopiekorrektur - die erste reversible Alternative in der refraktiven Chirurgie.  Contactologia. 1999;  21 172-191
  PubMedGoogle Scholar
• 47 Höh H. Hyperopiekorrektur mit intrastromalen Implantaten.  Klin Monatsbl Augenheilkd. 1999;  215 (Suppl 12) 6
  PubMedGoogle Scholar
• 48 Husinsky W, Mitterer S, Altmann J, Grabner G, Baumgartner I, Skorpik F. et al . Corneal lathing using the excimer laser and a computer-controlled positioning system: Part II - Variable trephination of corneal buttons.  Refract Corneal Surg. 1991;  7 (5) 385-389
  PubMedGoogle Scholar
• 49 Kaufman H E, Werblin T P. Epikeratophakia for the treatment of keratoconus.  Am J Ophthalmol. 1982;  93 (3) 342-347
  PubMedGoogle Scholar
• 50 Koenig S B, Hamano T, Yamaguchi T, Kimura T, McDonald M B, Kaufman H E. Refractive keratoplasty with hydrogel implants in primates.  Ophthalmic Surg. 1984;  14 225-229
  PubMedGoogle Scholar
• 51 Kritzinger M S. KeraVision Intacs for post-LASIK correction. KeraVision Intacs: Expanding the horizons of refractive technology. Chateney-Malabry, France; KeraVision Europe 2000: 10-12
  Google Scholar
• 52 Kuhne F, Simon G, Parel J M. Les resultats de 2 ans d'experimentation animale des anneaux intrastromaux en polyoxyde d'ethylene reticule.  J Fr Ophtalmol. 1994;  17 83
  PubMedGoogle Scholar
• 53 Lane S L, Lindstrom R L, Cameron J D, Thomas R H, Mindrup E A, Waring G O, McCarey B E, Binder P S. Polysulfone corneal lenses.  J Cataract Refract Surg. 1986;  12 (1) 50-60
  PubMedGoogle Scholar
• 54 Linebarger E J, Song D, Ruckhofer J, Schanzlin D J. Intacs: the intrastromal corneal ring.  Int Ophthalmol Clin. 2000;  40 (3) 199-208
  PubMedGoogle Scholar
• 55 Lovisolo C F. Corneal and ocular bioptics with Intacs inserts. Intacs inserts: Expanding the horizons of refractive technology. Chateney-Malabry, France; KeraVision Europe 2001: 9-11
  Google Scholar
• 56 Marinho A. An alternative approach to treating keratoconus with Intacs inserts. Intacs inserts: Expanding the horizons of refractive technology. Chateney-Malabry, France; KeraVision Europe 2001: 22-24
  Google Scholar
• 57 McCarey B, Andrews D. Refractivekeratoplasty with intrastromal hydrogel implants in primates.  Invest Ophthalmol Vis Sci. 1981;  21 107-115
  PubMedGoogle Scholar
• 58 McDonald M B, Kaufman H E, Aquavella J V, Durrie D S, Hiles D A, Hunkeler J D, Keates R H, Morgan K S, Sanders D R. The nationwide study of epikeratophakia for myopia.  Am J Ophthalmol. 1987;  103 (3 Pt 2) 375-383
  PubMedGoogle Scholar
• 59 Morgan K S, McDonald M B, Hiles D A, Aquavella J V, Durrie D S, Hunkeler J D, Kaufman H E, Keates R H, Sanders D R. The nationwide study of epikeratophakia for aphakia in children.  Am J Ophthalmol. 1987;  103 (3 Pt 2) 366-374
  PubMedGoogle Scholar
• 60 Morgan K S, McDonald M B, Hiles D A, Aquavella J V, Durrie D S, Hunkeler J D, Kaufman H E, Keates R H, Sanders D R. The nationwide study of epikeratophakia for aphakia in older children.  Ophthalmology. 1988;  95 (4) 526-532
  PubMedGoogle Scholar
• 61 Nagy Z, Krasznai G, Modis L, Sefcsik I, Furka I, Miko I. Intrastromal corneal ring, a new refractive surgical technique to decrease myopia. Experimental and clinical results.  Acta Chir Hung. 1997;  36 (1 - 4) 248-250
  PubMedGoogle Scholar
• 62 Nosé W, Neves R A, Schanzlin D J, Belfort R. Intrastromal corneal ring-one year results of first implants in humans: a preliminary nonfunctional eye study.  Refract Corneal Surg. 1993;  9 452-458
  PubMedGoogle Scholar
• 63 Nose W, Neves R A, Burris T. The Intracorneal Ring: 12-month sighted myopic eyes.  J Refract Surg. 1996;  12 20-28
  PubMedGoogle Scholar
• 64 Patel S, Marshall J, Fitzke F W. Model for deriving the optical performance of the myopic eye corrected with an intracorneal ring.  J Refract Surg. 1995;  11 (4) 248-252
  PubMedGoogle Scholar
• 65 Parks R A, McCarey B E, Knight P M, Storie B R. Intrastromal crystalline deposits following hydrogel keratophakia in monkeys.  Cornea. 1993;  12 29-34
  PubMedGoogle Scholar
• 66 Pinsky P, Datye D, Silvestrini T. Numerical simulation of topographical alterations in the cornea after ICR (intrastromal ring implantat) placement.  Invest Ophthalmol Vis Sci. 1995;  36 (suppl) S309
  PubMedGoogle Scholar
• 67 Quantock A, Kincaid M, Schanzlin D. Stromal healing following explantation of an ICR (Intrastromal Corneal Ring) from a nonfunctional human eye.  Arch Ophthalmol. 1995;  113 208-209
  PubMedGoogle Scholar
• 68 Rapuano C J, Sugar A, Koch D D, Agapitos P J, Culbertson W W, de Luise V P. et al . Intrastromal corneal ring segments for low myopia: a report by the American Academy of Ophthalmology.  Ophthalmology . 2001;  108 (10) 1922-1928
  CrossrefPubMedGoogle Scholar
• 69 Reynolds A E. Intracorneal PMMA ring passing animal tests. In theory, device flattens or steepens cornea without touching visual axis.  Ocular Surg News. 1988;  6 21
  PubMedGoogle Scholar
• 70 Robman L, Shusterov Y. Ring tunnel keratoplasty in high and extreme myopia correction.  Aust N Z J Ophthalmol. 1998;  26, Suppl 1 S26-28
  PubMedGoogle Scholar
• 71 Rodrigues M M, McCarey B E, Waring G O, Hidayat A A, Kruth H S. Lipid deposits posterior to impermeable intracorneal lenses in rhesus monkeys: Clinical, histochemical, and ultrastructural studies.  Refract Corneal Surg. 1990;  6 32-37
  PubMedGoogle Scholar
• 72 Ruckhofer J, Alzner E, Grabner G. Der Intrastromale Corneale Ring (KeraVision Ring, ICR, ICRS) - Eine neue, reversible Methode zur Korrektur der niedrigen Myopie. Entwicklung, kritischer Vergleich mit RK und PRK, eigene refraktive Ergebnisse und Nebenwirkungen der ersten 25 Eingriffe.  Spektrum Augenheilkd. 1997;  11 247-254
  PubMedGoogle Scholar
• 73 Ruckhofer J, Alzner E, Grabner G. Intrastromale Corneale Ring Segmente (ICRS®, KeraVision®-Ring). 1-Jahres-Ergebnisse der ersten 25 Eingriffe.  Klin Monatsbl Augenheilkd. 1998;  213 147-153
  PubMedGoogle Scholar
• 74 Ruckhofer J, Stoiber J, Alzner E, Grabner G. Intrastromale Corneale Ringsegmente (ICRS®, KeraVision-Ring®, Intacs®): Klinische Ergebnisse nach 2 Jahren.  Klin Monatsbl Augenheilkd. 2000;  216 133-142
  Article in Thieme ConnectPubMedGoogle Scholar
• 75 Ruckhofer J, Böhnke M, Alzner E, Grabner G. Confocal microscopy after implantation of intrastromal corneal ring segments.  Ophthalmology. 2000;  107 (12) 16-23
  PubMedGoogle Scholar
• 76 Ruckhofer J, Linebarger E J, Schanzlin D J. Goldmann applanation tonometry after Intacs corneal ring segments.  J Cataract Refract Surg. 2000;  26 (9) 1332-1338
  CrossrefPubMedGoogle Scholar
• 77 Ruckhofer J. Additive Refractive Surgery: Products and Techniques. „Surgically Induced Astigmatism after Intacs”. Boston; Ophthalmology Interactive (CDROM) 2000
  Google Scholar
• 78 Ruckhofer J, Twa M D, Schanzlin D J. Clinical characterization of lamellar channel deposits after Intacs.  J Cataract Refract Surg. 2000;  26 (10) 1473-1479
  CrossrefPubMedGoogle Scholar
• 79 Ruckhofer J, Stoiber J, Alzner E, Grabner G. European multicenter (MECCA) study of intrastromal corneal ring segments (ICRS®): 1-year results. Part I: refractive outcome.  J Cataract Refract Surg. 2001;  27 (2) 277-286
  CrossrefPubMedGoogle Scholar
• 80 Ruckhofer J, Stoiber J, Alzner E, Grabner G. for the MECCA Study Group . European multicenter (MECCA) study of intrastromal corneal ring segments (ICRS®): 1-year results. Part II: complications, visual symptoms, and patient satisfaction.  J Cataract Refract Surg. 2001;  27 (2) 287-296
  CrossrefPubMedGoogle Scholar
• 81 Schanzlin D J, Asbell P A, Burris T E, Durrie D S. The intrastromal corneal ring segments. Phase II results for the correction of myopia.  Ophthalmology. 1997;  104 (7) 1067-1078
  PubMedGoogle Scholar
• 82 Schanzlin D J. Studies of intrastromal corneal ring segments for the correction of low to moderate myopic refractive errors.  Tr Am Ophth Soc. 1999;  47 815-890
  PubMedGoogle Scholar
• 83 Schanzlin D J, Abbott R L, Asbell P A, Assil K K, Burris T E, Durrie D S. et al . Two-Year Outcomes of ICRS® (Intrastromal Corneal Ring Segments) for the Correction of Myopia.  Ophthalmology. 2001;  108 (9) 1688-1694
  CrossrefPubMedGoogle Scholar
• 84 Siganos C S, Kymionis G D, Astyrakakis N, Pallikaris I G. Management of corneal ectasia after laser in situ keratomileusis with INTACS.  J Refract Surg. 2002;  18 (1) 43-46
  PubMedGoogle Scholar
• 85 Simon G, Barraquer I, Barraquer E. Refractive modeling of the cornea by intrastromal rings. ARVO abstracts.  Invest Ophthalmol Vis Sci. 1989;  30 187
  PubMedGoogle Scholar
• 86 Suiter B G, Twa M D, Ruckhofer J, Schanzlin D J. A comparison of visual acuity, predictability, and visual function outcomes after intracorneal ring segments and laser in situ keratomileusis.  Trans Am Ophthalmol Soc. 2000;  98 51-55, discussion 55 - 57
  PubMedGoogle Scholar
• 87 Thibos L N, Horner D. Power vector analysis of the optical outcome of refractive surgery.  J Cataract Refract Surg. 2001;  27 (1) 80-85
  CrossrefPubMedGoogle Scholar
• 88 Twa M D, Karpecki P M, King B J, Linn S H, Durrie D S, Schanzlin D J. One-year results from the phase III investigation of the KeraVision Intacs.  J Am Optom Assoc. 1999;  70 515-524
  PubMedGoogle Scholar
• 89 Twa M D, Hurst T, Walker J, Waring G O, Schanzlin D J. Diurnal stability of refraction after implantation with intracorneal ring segments.  J Cataract Refract Surg. 2000;  26 516-523
  CrossrefPubMedGoogle Scholar
• 90 Twa M D, Ruckhofer J, Schanzlin D J. Surgically induced astigmatism after Intacs intrastromal corneal ring segments.  J Cataract Refract Surg. 2001;  27 (3) 411-415 , Ophthalmology 1984 Oct; 91 (10): 1170 - 1175
  CrossrefPubMedGoogle Scholar
• 91 Wagoner M D, Smith S D, Rademaker W J, Mahmood M A. Penetrating keratoplasty vs. epikeratoplasty for the surgical treatment of keratoconus.  J Refract Surg. 2001;  17 (2) 138-146
  PubMedGoogle Scholar
• 92 Werblin T P, Kaufman H E. Epikeratophakia: the surgical correction of aphakia. II. Preliminary results in a non-human primate model.  Curr Eye Res. 1981;  1 (3) 131-137
  PubMedGoogle Scholar
• 93 Yamaguchi T, Koenig S B, Hamano T, Kimura T, Santana E, McDonald M B. et al . Electron microscopic study of intrastromal hydrogel implants in primates.  Ophthalmology. 1984;  91 1170-1175
  PubMedGoogle Scholar

Dr. Josef Ruckhofer

Landesklinik für Augenheilkunde und Optometrie · St. Johanns Spital · Landeskliniken Salzburg

Müllner Hauptstraße 48

5020 Salzburg · Österreich

Email: j.ruckhofer@lks.at