Contact Lens & Anterior Eye
Volume 33, Issue 4 , Pages 157-166 , August 2010

Keratoconus: A review

  • Miguel Romero-Jiménez

      Affiliations

    • MGR Doctores, Madrid, Spain
  • ,
  • Jacinto Santodomingo-Rubido

      Affiliations

    • Menicon Co., Ltd (Madrid Office), Iglesia 9, Apartamento 106, 28220 Majadahonda, Madrid, Spain
    • Corresponding Author InformationCorresponding author. Tel.: +34 610 832 234; fax: +34 916 388 774.
  • ,
  • James S. Wolffsohn

      Affiliations

    • Ophthalmic Research Group, Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK

References 

  1. Nottingham J. Practical observations on conical cornea. London: Churchill, London; 1984;p. 1–19
  2. Zadnik K, Barr JT, Gordon MO, Edrington TB CLEK Study Group. Biomicroscopic signs and disease severity in keratoconus. Cornea. 1996;15:139–146
  3. Kennedy RH, Bourne WM, Dyer JA. A 48-year clinical and epidemiologic study of keratoconus. Am J Ophthalmol. 1986;101:267–273
  4. Zadnik K, Steger-May K, Fink BA, Joslin CE, Nichols JJ, Rosenstiel CE, et al. Between-eye asymmetry in keratoconus. Cornea. 2002;21:671–679
  5. Chopra I, Jain AK. Between eye asymmetry in keratoconus in an Indian population. Clin Exp Optom. 2005;88:146–152
  6. Auffarth GU, Wang L, Völcker HE. Keratoconus evaluation using the Orbscan topography system. J Cataract Refract Surg. 2000;26:222–228
  7. Prisant O, Legeais , Renard G. Superior keratoconus. Cornea. 1997;16:693–694
  8. Weed KH, McGhee CN, Mac Ewen CJ. Atypical unilateral superior keratoconus in young males. Contact Lens Anterior Eye. 2005;28:177–179
  9. Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998;42:297–319
  10. Rahmen W, Anwar S. An unusual case of keratoconus. J Pediatr Ophthalmol Strabismus. 2006;43:373–375
  11. Rabinowitz YS, Yang H, Rasheed K, Li X. Longitudinal analysis of the fellow eyes in unilateral keratoconus. Invest Ophthalmol Vis Sci. 2003;44:E-Abstract 1311
  12. Krachmer JH, Feder RS, Belin MW. Keratoconus and related non-inflammatory corneal thinning disorders. Surv Ophthalmol. 1984;28:293–322
  13. Li X, Rabinowitz YS, Rasheed K, Yang H. Longitudinal study of the normal eyes in unilateral keratoconus patients. Ophthalmology. 2004;111:440–446
  14. Stein HA, Stein RM, Freeman MI. The ophthalmic assistant: a text for allied and associated ophthalmic personnel. Canada: Elsevier Mosby; 2006;p. 396
  15. Owens H, Gamble G. A profile of keratoconus in New Zealand. Cornea. 2003;22:122–125
  16. Weed KH, Mc Ghee CN. Referral patterns, treatment management and visual outcome in keratoconus. Eye. 1998;12:663–668
  17. Pearson AR, Soneji B, Sarvananthan N, Sandford-Smith JH. Does ethnic origin influence the incidence or severity of keratoconus?. Eye. 2000;14:625–628
  18. Wagner H, Barr JT, Zadnik K. Collaborative longitudinal evaluation of keratoconus (CLEK) study: methods and findings to date. Contact Lens Anterior Eye. 2007;30:223–232
  19. Weed KH, MacEwen CJ, Giles T, Low J, McGhee CN. The Dundee university Scottish Keratoconus study: demographics, corneal signs, associated diseases, and eye rubbing. Eye. 2008;22:534–541
  20. Owens H, Gamble GD, Bjornholdt MC, Boyce NK, Keung L. Topographic indications of emerging keratoconus in teenage New Zealanders. Cornea. 2007;26:312–318
  21. Georgiou T, Funnell CL, Cassels-Brown A, O’Conor R. Influence of ethnic origin on the incidence of keratoconus and associated atopic disease in Asians and white patients. Eye. 2004;18:379–383
  22. Arntz A, Durán JA, Pijoán JI. Subclinical keratoconus diagnosis by elevation topography. Arch Soc Esp Oftalmol. 2003;78:659–664
  23. Fleischer B. Über Keratoconus und eigenartige Pigmenfbildung in der kornea. München Med Wschr. 1906;53:625–626
  24. Barraquer-Somers E, Chang CC, Green WR. Corneal epithelial iron deposition. Ophthalmology. 1983;90:729–734
  25. Davis LJ, Barr JT, Vanotteren D. Transitient rigid lens-induced striae in keratoconus. Optom Vis Sci. 1993;70:216–219
  26. Thota S, Miller WL, Bergmanson JP. Acute corneal hydrops: a case report including confocal and histopathological considerations. Contact Lens Anterior Eye. 2006;29:69–73
  27. Perry HD, Buxton JN, Fine BS. Round and oval cones in Keratoconus. Ophthalmology. 1980;87:905–909
  28. Hom M, Bruce AS. Manual of contact lens prescribing and fitting. London: Butterworth-Heineman; 2006;p. 503–44
  29. McMahon TT, Szczotka-Flynn L, Barr JT, Anderson RJ, Slaughter ME, Lass JH, et al. A new method for grading the severity of keratoconus: the keratoconus severity score (KSS). Cornea. 2006;25:794–799
  30. McMahon TT, Robin JB, Scarpulla KM, Putz JL. The spectrum of topography found in keratoconus. CLAO J. 1991;17:198–204
  31. Abad JC, Rubinfeld RS, Del Valle M, Belin MW, Kurstin JM, Vertical D. A novel topographic pattern in some keratoconus suspects. Ophthalmology. 2007;114:1020–1026
  32. Amsler M. Le keratocone fruste au javal. Ophtalmologica. 1938;96:77–83
  33. Amsler M. Keratocone classique et keratocone fruste, arguments unitaires. Ophtalmologica. 1946;111:96–101
  34. Randleman JB, Russell B, Ward MA, Thompson KP, Stulting RD. Risk factors and prognosis for corneal ectasia after LASIK. Ophthalmology. 2003;110:267–275
  35. Chiang RK, Park AJ, Rapuano CJ, Cohen EJ. Bilateral keratoconus after LASIK in keratoconus patient. Eye Contact Lens. 2003;29:90–92
  36. Binder PS, Lindstrom RL, Stulting RD, Donnenfeld E, Wu H, McDonnell P, et al. Keratoconus and corneal ectasia after LASIK. J Refract Surg. 2005;21:749–752
  37. Rabinowitz YS, McDonnell PJ. Computer-assisted corneal topography in keratoconus. Refract Corneal Surg. 1989;5:400–408
  38. Maeda N, Klyce SD, Smolek MK, Thompson HW. Automated keratoconus screening with corneal topography analysis. Invest Ophtalmol Vis Sci. 1994;35:2749–2757
  39. Smolek MK, Klyce SD. Current keratoconus detection methods compared with a neural network approach. Invest Ophthalmol Vis Sci. 1997;74:2290–2299
  40. Maeda N, Klyce SD, Smolek MK. Neural network classification of corneal topography. Preliminary demonstration. Invest Ophtalmol Vis Sci. 1995;36:1947–1948
  41. Schwiegerling J, Greivenkamp JE. Keratoconus detection based on videokeratoscopic height data. Optom Vis Sci. 1996;73:721–728
  42. Rabinowitz YS, Rasheed K. KISA% index: a quantitative videokeratography algorithm embodying minimal topographic criteria for diagnosing keratoconus. J Cataract Refract Surg. 1999;25:1327–1335
  43. Mahmoud AM, Roberts CJ, Lembach RG, Twa MD, Herderick EE, McMahon TT. CLMI: the cone location and magnitude index. Cornea. 2008;27:480–487
  44. Li Y, Meisler DM, Tang M, Lu AT, Thakrar V, Reiser BJ, et al. Keratoconus diagnosis with optical coherence tomography pachymetry mapping. Ophthalmology. 2008;115:2159–2166
  45. Gobbe M, Guillon M. Corneal wavefront aberration measurement to detect keratoconus patients. Contact Lens Anterior Eye. 2005;28:57–66
  46. Emre S, Doganay S, Yologlu S. Evaluation of anterior segment parameters in keratoconic eyes measured with Pentacam system. J Cataract Refract Surg. 2007;33:1708–1712
  47. Ortiz D, Piñero D, Shabayek MH, Arnalich-Montiel F, Alió JL. Corneal biomechanical properties in normal, post-laser in situ keratomileusis, and keratoconic eyes. J Cataract Refract Surg. 2007;33:1371–1375
  48. Piñero D, Alió JL, Alesón A, Escaf M, Miranda M. Pentacam posterior and anterior corneal aberrations in normal and keratoconic eyes. Clin Exp Optom. 2009;92:297–303
  49. de Sanctis U, Loiacono C, Richiardi L, Turco D, Mutani B, Grignolo FM. Sensitivity and specifity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/subclinical keratoconus. Ophthalmology. 2008;115:1534–1539
  50. Sawaguchi S, Fukuchi T, Abe H, Kaiya T, Sugar J, Yue BY. Three-dimensional scanning electron microscopic study of keratoconus corneas. Arch Ophthalmol. 1998;116:62–68
  51. Weed KH, MacEwen CJ, Cox A, McGhee CN. Quantitative analysis of corneal microstructure in keratoconus utilising in vivo confocal microscopy. Eye. 2007;21:614–623
  52. Sherwin T, Brookes NH. Morphological changes in keratoconus: pathology or pathogenesis. Clin Experiment Ophthalmol. 2004;32:211–217
  53. Meek KM, Tuft SJ, Huang Y, Gill PS, Hayes S, Newton RH, et al. Changes in collagen orientation and distribution in keratoconus corneas. Invest Opthalmol Vis Sci. 2005;46:1948–1956
  54. Ku JY, Niederer RL, Patel DV, Sherwin T, McGhee CN. Laser scanning in vivo confocal analysis of keratocyte density in keratoconus. Ophthalmology. 2008;115:845–850
  55. Patel DV, Ku JY, Johnson R, McGhee CN. Laser scanning in vivo confocal microscopy and quantitative aesthesiometry reveal decreased corneal inervation and sensation in keratoconus. Eye. 2009;23:586–592
  56. Hammerstein W. Genetics of conical cornea (author's transl). Albrecht Von Graefes Arch Klin Exp Ophthalmol. 1974;190:293–308
  57. Gónzalez V, McDonnell PJ. Computer-assisted corneal topography in parents of patients with keratoconus. Arch Ophthalmol. 1992;110:1413–1414
  58. Wang Y, Rabinowitz YS, Rotter JI, Yang H. Genetic epidemiological study of keratoconus: evidence for major gene determination. Am J Med Genet. 2000;93:403–409
  59. Parker J, Ko WW, Pavlopoulos G, Wolfe PJ, Rabinowitz YS, Feldman ST. Videokeratography of keratoconus in monozygotic twins. J Refract Surg. 1996;12:180–183
  60. Weed KH, MacEwen CJ, McGhee CN. The variable expression of keratoconus within monozygotic twins: Dundee university scottish keratoconus study (DUSKS). Contact Lens Anterior Eye. 2006;29:123–126
  61. Bechara SJ, Waring GO, Insler MS. Keratoconus in two pairs of identical twins. Cornea. 1996;15:90–93
  62. McMahon TT, Shin JA, Newlin A, Edrington TB, Sugar J, Zadnik K. Discordance for keratoconus in two pairs of monozygotic twins. Cornea. 1999;18:444–451
  63. Schmitt-Bernard C, Schneider CD, Blanc D, Arnaud B. Keratographic analysis of a family with keratoconus in identical twins. J Cataract Refract Surg. 2000;26:1830–1832
  64. Aknin C, Allart JF, Rouland JF. Unilateral keratoconus and mirror image in a pair of monozygotic twins. J Fr Ophtalmol. 2007;30:899–902
  65. Fullerton J, Paprocki P, Foote S, Mackey DA, Williamson R, Forrest S. Identify-by-descent approach to gene localisation in eight individuals affected by keratoconus from north-west Tasmania, Australia. Hum Genet. 2002;110:462–470
  66. Tyynismaa H, Sistonen P, Tuupanen S, Tervo T, Dammert A, Latvala T, et al. A locus for autosomal dominant keratoconus: linkage to 16q22.3-q23.1 in Finnish families. Invest Ophthalmol Vis Sci. 2002;43:3160–3164
  67. Hughes AE, Dash DP, Jackson AJ, Frazer DG, Silvestri G. Familiar keratoconus with cataract: linkage to the long arm of chromosome 15 and exclusion of candidate genes. Invest Ophthalmol Vis Sci. 2003;44:5063–5066
  68. Brancati F, Valente EM, Sarkozy A, Fehèr J, Castori M, Del Duca P, et al. A locus for autosomal dominant keratoconus maps to human chromosome 3p14-q13. J Med Genet. 2004;41:188–192
  69. Hutchings H, Ginisty H, Le Gallo M, Levy D, Stoësser F, Rouland JF, et al. Identification of a new locus for isolated familial keratoconus at 2p24. J Med Genet. 2005;42:88–94
  70. Tang YG, Rabinowitz YS, Taylor KD, Li X, Hu M, Picornell Y, et al. Genomewide linkage scan in a multigeneration Caucasian pedigree identifies a novel locus for keratoconus on chromosome 5q14.3-q21.1. Genet Med. 2005;7:397–405
  71. Li X, Rabinowitz YS, Tang YG, Picornell Y, Taylor KD, Hu M, et al. Two-stage genome-wide linkage scan in keratoconus sib pair families. Invest Ophthalmol Vis Sci. 2006;47:3791–3795
  72. Bisceglia L, De Bonis P, Pizzicoli C, Fischetti L, Laborante A, Di Perna M, et al. Linkage analysis in keratoconus: replication of locus 5q21.2 and identification of other suggestive Loci. Invest Ophthalmol Vis Sci. 2009;50:1081–1086
  73. Héon E, Greenberg A, Kopp KK, Rootman D, Vincent AL, Billingsley G, et al. VSX1: a gene for posterior polymorphous dystrophy and keratoconus. Hum Mol Genet. 2002;11:1029–1036
  74. Bisceglia L, Ciaschetti M, De Bonis P, Campo PA, Pizzicoli C, Scala C, et al. VSX1 mutational analysis in a series of Italian patients affected by keratoconus: detection of a novel mutation. Invest Ophthalmol Vis Sci. 2005;46:39–45
  75. Eran P, Almogit A, David Z, Wolf HR, Hana G, Yaniv B, et al. The D144E substitution in the VSX1gene: a non-pathogenic variant or disease causing mutation?. Ophthalmic Genet. 2008;29:53–59
  76. Aldave AJ, Yellore VS, Salem AK, Yoo GL, Rayner SA, Yang H, et al. No VSX1 gene mutations associated with keratoconus. Invest Ophthalmol Vis Sci. 2006;47:2820–2822
  77. Liskova P, Ebenezer ND, Hysi PG, Gwilliam R, El-Ashry MF, Moodaley LC, et al. Molecular analysis of the VSX1 gene in familial keratoconus. Mol Vis. 2007;4:1887–1891
  78. Tang YG, Picornell Y, Su X, Li X, Yang H, Rabinowitz YS. Three VSX1 gene mutations, L159M, R166W, and H244R, are not associated with keratoconus. Cornea. 2008;27:189–192
  79. Määttä M, Väisänen T, Väisänen MR, Pihlajaniemi T, Tervo T. Altered expression of type XIII collagen in keratoconus and scarred human corneas: increased expression in scarred cornea is associated with myofibroblast transformation. Cornea. 2006;25:448–453
  80. Määttä M, Heljasvaara R, Sormunen R, Pihlajaniemi T, Autio-Harmainen H, Tervo T. Differential expression of collagen types XVIII/endostatin and XV in normal, keratoconus and scarred human corneas. Cornea. 2006;25:341–349
  81. Fukuchi T, Yue BY, Sugar J, Lam S. Lysosomal enzyme activities in conjunctival tissues of patients with keratoconus. Arch Ophthalmol. 1994;112:1368–1374
  82. Sawaguchi S, Yue BY, Sugar J, Gilboy JE. Lysosomal abnormalities in keratoconus. Arch Ophthalmol. 1989;107:1507–1510
  83. Sawaguchi S, Twining SS, Yue BY, Chang SH, Zhou X, Loushin G, et al. Alpha 2 macroglobulin levels in normal human and keratoconus corneas. Invest Ophthalmol Vis Sci. 1994;35:4008–4014
  84. Bereau J, Fabre EJ, Hecquet C, Pouliquen Y, Lorans G. Modification of prostaglandin E2 and collagen synthesis in keratoconus fibroblasts associated with an increase of interleukin-1 alpha receptor number. CR Acad Sci III. 1993;316:425–430
  85. Wilson SE, He YG, Weng J, Li Q, McDowall AW, Vital M, et al. Epithelial injury induces keratocyte apoptosis: hypothesized role for the interleukin-1 system in the modulation of corneal tissue organization and wound healing. Exp Eye Res. 1996;62:325–337
  86. Bron A, rabinowitz YS. Corneal dystrophies and keratoconus. Curr Opin Ophthalmol. 1996;7:71–82
  87. Lema I, Durán JA, Ruiz C, Díez-Feijoo E, Acera A, Merayo J. Inflammatory response to contact lenses in patients with keratoconus compared with myopic subjects. Cornea. 2008;27:758–763
  88. Lema I, Sobrino T, Durán JA, Brea D, Díez-Feijoo E. Subclinical keratoconus and inflammatory molecules from tears. Br J Ophthalmol. 2009;93:820–824
  89. Klintworth GK, Damms T. Corneal dystrophies and keratoconus. Curr Opin Ophthalmol. 1995;6:44–56
  90. Gondhowiardjo TD, van Haeringen NJ. Corneal aldehyde dehydrogenase, glutathione reductase, and glutathione S-transferase in pathologic corneas. Cornea. 1993;12:310–314
  91. Behndig A, Karlsson K, Johansson BO, Brännström T, Marklund SL. Superoxide dismutase isoenzymes in the human eye. Invest Ophthalmol Vis Sci. 1998;39:471–475
  92. Kenney MC, Brown DJ. The cascade hypothesis of keratoconus. Contact Lens Anterior Eye. 2003;26:139–146
  93. Copeman PW. Eczema and keratoconus. Br Med J. 1965;2:977–979
  94. Gasset AR, Hinson WA, Frias JL. Keratoconus and atopic disease. Ann Ophthalmol. 1978;10:991–994
  95. Lowell FC, Carroll JM. A study of the occurrence of atopic traits in patients with keratoconus. J Allergy Clin Immunol. 1970;46:32–39
  96. Bawazerr AM, Hodge WG, Lorimer B. Atopy and keratoconus: a multivariate analysis. Br J Ophthalmol. 2000;84:834–836
  97. McMonnies CW. Abnormal rubbing and keratectasia. Eye Contact Lens. 2007;33:265–271
  98. McMonnies CW. The evidentiary significance of case reports: eye rubbing and keratoconus. Optom Vis Sci. 2008;85:262–269
  99. Kaya V, Utine CA, Altunsoy M, Oral D, Yilmaz OF. Evaluation of the corneal topographic characteristics of keratoconus with orbscan II in patients with and without atopy. Cornea. 2007;26:945–948
  100. Hargrave S, Chu Y, Mendelblatt D, Mayhew E, Niederkorn J. Preliminary findings in corneal allograft rejection in patients with keratoconus. Am J Ophthalmol. 2003;135:452–460
  101. Gasset AR, Houde WL, Garcia-Bengochea M. Hard contact lens wear as an environmental risk in keratoconus. Am J Ophthalmol. 1978;85:339–341
  102. Cullen JF, Buttler HG. Mongolism (Down's Syndrome) and keratoconus. Br J Ophthalmol. 1963;47:321–330
  103. Shrapiro MB, France TD. The ocular features of Down's syndrome. Am J Ophthalmol. 1985;99:659–663
  104. Elder MJ. Leber congenital amaurosis and its association with keratoconus and keratoglobus. J Pediatr Ophthalmol Strabismus. 1994;31:38–40
  105. Damji KF, Sohocki MM, Khan R, Gupta SK, Rahim M, Loyer M, et al. Leber's congenital amaurosis with anterior keratoconus in Pakistani families is caused by the Trp278X mutation in the AIPL1 gene on 17p. Can J Ophthalmol. 2001;36:252–259
  106. Roberston I. Keratoconus and Ehlers-Dalos syndrome. A new aspect of keratoconus. Med J Aust. 1975;1:571–573
  107. Kuming BS, Joffe L. Ehlers-Danlos syndrome associated with keratoconus. A case report. S Afr Med J. 1977;52:403–405
  108. Beckh U, Schonherr U, Naumann GO. Autosomal dominant keratoconus as the chief ocular symptom in Lobstein osteogenesis imperfecta tarda. Klin Monatsbl Augenheilkd. 1995;206:268–272
  109. Sharif KW, Casey TA, Coltart J. Prevalence of mitral valve prolapse in keratoconus patients. J R Soc Med. 1992;85:446–448
  110. Litcher H, Loya N, Sagie A, Cohen N, Muzmacher L, Yassur Y, et al. Keratoconus and mitral valve prolapse. Am J Ophthalmol. 2000;129:667–668
  111. Street DA, Vinokur ET, Waring GO, Pollak SJ, Clements SD, Perkins JV. Lack of association between keratoconus, mitral valve prolapse, and joint hypermobility. Ophthalmology. 1991;98:170–176
  112. Fick AE. A contact-lens. 1888 (translation). Arch Ophthalmol. 1988;106:1373–1377
  113. Bilgin LK, Yilmaz S, Araz B, Yüksel SB, Sezen T. 30 years of contact lens prescribing for keratoconic patients in Turkey. Contact Lens Anterior Eye. 2009;32:16–21
  114. Zadnik K, Barr JT, Edrington TB, Everett DF, Jameson M, McMahon TT, et al. Baseline findings in the collaborative longitudinal evaluation of keratoconus (CLEK) study. Invest Ophthalmol Vis Sci. 1998;39:2537–2546
  115. Lim N, Vogt U. Characteristics and functional outcomes of 130 patients with keratoconus attending a specialist contact lens clinic. Eye. 2002;16:54–59
  116. González-Méijome JM, Jorge J, de Almeida JB, Parafita MA. Soft contact lenses for keratoconus: case report. Eye Contact Lens. 2006;32:143–147
  117. Marsack JD, Parker KE, Applegate RA. Performance of wavefront-guided soft lenses in three keratoconus subjects. Optom Vis Sci. 2008;85:E1172–E1178
  118. Katsoulos C, Karageorgiadis L, Vasileiou N, Mousafeiropoulos T, Asimellis G. Customized hydrogel contact lenses for keratoconus incorporating correction for vertical coma aberration. Ophthalmic Physiol Opt. 2009;29:321–329
  119. McMonnies CW. Keratoconus fittings: apical clearance or apical support?. Eye Contact Lens. 2004;30:147–155
  120. Edrington TB, Gundel RE, Libassi DP, Wagner H, Pierce GE, Walline JJ, et al. Variables affecting rigid contact lens comfort in the collaborative longitudinal evaluation of keratoconus (CLEK) study. Optom Vis Sci. 2004;81:182–188
  121. Zadnik K, Barr JT, Steger-May K, Edrington TB, McMahon TT, Gordon MO. Comparison of flat and steep rigid contact lens fitting methods in keratoconus. Optom Vis Sci. 2005;82:1014–1021
  122. Betts AM, Mitchell GL, Zadnik K. Visual performance and comfort with the Rose K lens for keratoconus. Optom Vis Sci. 2002;79:493–501
  123. Lee JL, Kim MK. Clinical performance and fitting characteristics with a multicurve lens for keratoconus. Eye Contact Lens. 2004;30:20–24
  124. Hu CY, Tung HC. Managing keratoconus with reverse-geometry and dual-geometry contact lenses: a case report. Eye Contact Lens. 2008;34:71–75
  125. Rubinstein MP, Sud S. The use of hybrid lenses in management of the irregular cornea. Contact Lens Anterior Eye. 1999;22:87–90
  126. Leal F, Lipener C, Chalita MR, Uras R, Campos M, Höfling-Lima AL. Hybrid material contact lens in keratoconus and myopic astigmatism patients. Arq Bras Oftalmol. 2007;70:247–254
  127. Pilskalns B, Fink BA, Hill RM. Oxygen demands with hybrid contact lenses. Optom Vis Sci. 2007;84:334–342
  128. Jaworski P, Wygledowska-Promieńska D, Gierek-Ciaciura S. Application of duo-systems (piggy back) in correction of keratoconus. Klin Oczna. 2004;106:629–632
  129. O’Donnell C, Maldonado-Codina C. A hyper-Dk piggyback contact lens system for keratoconus. Eye Contact Lens. 2004;30:44–48
  130. Sray WA, Cohen EJ, Rapuano CJ, Laibson PR. Factors associated with the need for penetrating keratoplasty in keratoconus. Cornea. 2002;21:784–786
  131. Gordon MO, Steger-May K, Szczotka-Flynn L, Riley C, Joslin CE, Weissman BA, et al. Baseline factors predictive of incident penetrating keratoplasty in keratoconus. Am J Ophthalmol. 2006;142:923–930
  132. Tuft SJ, Moodaley LC, Gregory WM, Davison CR, Buckley RJ. Prognostic factors for the progression of keratoconus. Ophthalmology. 1994;101:439–447
  133. Reeves SW, Stinnett S, Adelman RA, Afshari NA. Risk factors for progression to penetrating keratoplasty in patients with keratoconus. Am J Ophthalmol. 2005;140:607–611
  134. Watson SL, Ramsay A, Dart JK, Bunce C, Craig E. Comparison of deep lamellar keratoplasty and penetrating keratoplasty in patients with keratoconus. Ophthalmology. 2004;111:1676–1682
  135. Funnell CL, Ball J, Noble BA. Comparative cohort study of the outcomes of deep lamellar keratoplasty and penetrating keratoplasty for keratoconus. Eye. 2006;20:527–532
  136. Vabres B, Bosnjakowski M, Bekri L, Weber M, Pechereau A. Deep lamellar keratoplasty versus penetrating keratoplasty for keratoconus. J Fr Ophtalmol. 2006;29:361–371
  137. Krumeich JH, Kezirian GM. Circular keratotomy to reduce astigmatism and improve vision in stage I and II keratoconus. J Refract Surg. 2009;25:357–365
  138. Leccisotti A. Effect of circular keratotomy on keratoconus. J Cataract Refract Surg. 2006;32:2139–2141
  139. Kasparova EA. Pathogenetic basis for treatment of primary keratoconus by a combined method of excimer laser surgery (combination of photorefraction and phototherapeutic keratectomy). Vestn Oftalmol. 2002;118:21–25
  140. Bahar I, Levinger S, Kremer I. Wavefront-supported photorefractive keratectomy with the Bausch & Lomb Zyoptix in patients with myopic astigmatism and suspected keratoconus. J Refract Surg. 2006;22:533–538
  141. Alpins N, Stamatelatos G. Customized photoastigmatic refractive keratectomy using combined topographic and refractive data for myopia and astigmatism in eyes with forme fruste and mild keratoconus. J Cataract Refract Surg. 2007;33:591–602
  142. Doyle SJ, Hynes E, Naroo S, Shah S. PRK in patients with a keratoconic topography picture. The concept of a physiological ‘displaced apex syndrome’. Br J Ophthalmol. 1996;80:25–28
  143. Bilgihan K, Ozdek SC, Sari A, Hasanreisoglu B. Microkeratome-assisted lamellar keratoplasty for keratoconus: stromal sandwich. J Cataract Refract Surg. 2003;29:1267–1272
  144. Wagoner MD, Smith SD, Rademaker WJ, Mahmood MA. Penetrating keratoplasty vs. epikeratoplasty for the surgical treatment of keratoconus. J Refract Surg. 2001;17:138–146
  145. Buzard T, Tuengler A, Febbraro JL. Treatment of mild to moderate keratoconus with laser in situ keratomileusis. J Cataract Refract Surg. 1999;25:1600–1609
  146. Legeais JM, Parc C, d’Hermies F, Pouliquen Y, Renard G. Nineteen years of penetrating keratoplasty in the Hotel-Dieu Hospital in Paris. Cornea. 2001;20:603–606
  147. Lim L, Pesudovs K, Coster DJ. Penetrating keratoplasty for keratoconus: visual outcome and success. Ophthalmology. 2000;107:1125–1131
  148. Brierly SC, Izquierdo L, Mannis MJ. Penetrating keratoplasty for keratoconus. Cornea. 2000;19:329–332
  149. Nosé W, Neves RA, Burris TE, Schanzlin DJ, Belfort Júnior R. Intrastromal corneal ring: 12-month sighted myopic eyes. J Refract Surg. 1996;12:20–28
  150. Colin J, Cochener B, Savary G, Malet F. Correcting keratoconus with intracorneal rings. J Cataract Refract Surg. 2000;26:1117–1122
  151. Tomalla M, Cagnolati W. Modern treatment options for the therapy of keratoconus. Contact Lens Anterior Eye. 2007;30:61–66
  152. Zare MA, Hashemi H, Salri MR. Intracorneal ring segment implantation for the management of keratoconus: safety and efficacy. J Cataract Refract Surg. 2007;33:1886–1891
  153. Coskunseven E, Kymionis GD, Tsiklis NS, Atun S, Arslan E, Jankov MR, et al. One-year results of intrastromal corneal ring segment implantation (KeraRing) using femtosecond laser in patients with keratoconus. Am J Ophthalmol. 2008;145:775–779
  154. Shabayek MH, Alió JL. Intrastromal corneal ring segment implantation by femtosecond laser for keratoconus correction. Ophthalmology. 2007;114:1643–1652
  155. Spoerl E, Mrochen M, Sliney D, Trokel S, Seiler T. Safety of UVA-riboflavin cross-linking of the cornea. Cornea. 2007;26:385–389
  156. Wollensak G. Crosslinking treatment of progressive keratoconus: new hope. Curr Opin Ophthalmol. 2006;17:356–360
  157. Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE. Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: long-term results. J Cataract Refract Surg. 2008;34:796–801
  158. Chan CC, Sharma M, Wachler BS. Effect of inferior-segment Intacs with and without C3-R on keratoconus. J Cataract Refract Surg. 2007;33:75–80
  159. Mazzotta C, Balestrazzi A, Traversi C, Baiocchi S, Caporossi T, Tommasi C, et al. Treatment of progressive keratoconus by riboflavin-UVA-induced cross-linking of corneal collagen: ultrastructural analysis by Heidelberg Retinal Tomograph II in vivo confocal microscopy in humans. Cornea. 2007;26:390–397
  160. Colin J, Velou S. Implantation of Intacts and a refractive intraocular lens to correct keratoconus. J Cataract Reract Surg. 2003;29:832–834
  161. El-Raggal TM, Abdel Fattah AA. Sequential Intacts and Verisyse phakic intraocular lens for refractive improvement in keratoconic eyes. J Cataract Refract Surg. 2007;33:966–970
  162. Coskunseven E, Onder M, Kymionis GD, Diakonis VF, Arslan E, Tsiklis N, et al. Combined intacts and posterior chamber toric implantable collamer lens omplantation for keratoconic patients with extreme myopia. Am J Opthalmol. 2007;144:387–389
  163. Gasset AR, Kaufman HE. Thermokeratoplasty in the treatment of keratoconus. Am J Ophthalmol. 1975;79:226–232
  164. Sekundo W, Stevens JD. Surgical treatment of keratoconus at the turn of 20th century. J Refract Surg. 2001;17:69–73
  165. Aquavella JV, Smith RS, Shaw EL. Alterations in corneal morphology following thermokeratoplasty. Arch Ophthalmol. 1976;94:2082–2085
  166. Lyra JM, Trindade FC, Lyra D, Bezerra A. Outcomes of radiofrequency in advanced keratoconus. J Cataract Refract Surg. 2007;33:1288–1295
  167. Alió JL, Claramonte PJ, Cáliz A, Ramzy MI. Corneal modeling of keratoconus by conductive keratoplasty. J Cataract Refract Surg. 2005;31:190–197
  168. Hycl J, Janek M, Valesova L, Růzicka P, Donát A, Kuhnová G, et al. Experimental correction of irregular astigmatism in patients with keratoconus using diode laser thermal keratoplasty. Cesk Slov Oftalmol. 2003;59:382–391

PII: S1367-0484(10)00056-1

doi: 10.1016/j.clae.2010.04.006

Contact Lens & Anterior Eye
Volume 33, Issue 4 , Pages 157-166 , August 2010