Skip to main content
Log in

Typische Fragen aus der Rheumatologie an den Augenarzt und den kooperierenden Radiologen

Typical questions from the rheumatologist to the ophthalmologist and cooperating radiologist

  • Leitthema
  • Published:
Zeitschrift für Rheumatologie Aims and scope Submit manuscript

Zusammenfassung

Patienten mit rheumatologischen Problemen können im Augenbereich sehr heterogene akute oder chronische Symptome aufweisen. Neben Schmerzen und Bewegungseinschränkungen können Sehverlust und irreversible Zerstörung des Auges vorkommen. Das rote Auge, als leicht erkennbares Symptom, kann sehr viele verschiedene Ursachen haben. Benetzungsstörungen sind bei rheumatologischen Patienten häufig symptomatisch. Jeder ophthalmologische/rheumatologische Fall sollte auf mögliche Infektionserkrankungen oder ein Maskeradesyndrom geprüft werden. Liegen entzündliche Augenveränderungen vor, so sollte der Augenarzt aufgrund seiner spezifischen klinischen Kenntnisse den labordiagnostischen Weg vorgeben. Bei der juvenilen idiopathischen Arthritis muss je nach Gelenkbefallsmuster mit einem hohen Uveitisrisiko gerechnet werden. Während bei der Episkleritis eine zugrunde liegende Systemerkrankung eher selten beobachtet wird, ist diese bei einer Skleritis in der Hälfte aller Fälle gegeben. Ein Hornhautulkus ist immer ein ophthalmologischer Notfall und erfordert mitunter neben einer systemischen konservativen Therapie auch eine gezielte operative Versorgung. Das therapeutische Arsenal des Rheumatologen muss der Augenarzt in Einzelfällen durch lokale Medikamentengaben oder operative Maßnahmen bereichern. Das Ausmaß der entzündlichen Raumforderung im Auge bzw. in der Augenhöhle kann durch bildgebende Verfahren objektiviert werden. Es gibt wenige spezifische Nebenwirkungen rheumatologischer Therapeutika, die der Augenarzt kennen sollte, um selten auftretende schwerwiegende Nebenwirkungen frühzeitig zu erkennen.

Abstract

Patients with rheumatic disorders may suffer from various acute or chronic ocular symptoms. In addition to pain and motility disorders, loss of vision, and irreversible deterioration of the eye may occur. Red eye, a symptom easily identified, can be a sign of rheumatic involvement, but can also have a variety of other causes. Dry eye is frequently present in rheumatic patients. It is always important that infections and masquerade syndromes are ruled out in the differential diagnoses of any ocular inflammation. In cases of ocular inflammation the ophthalmologist should determine the diagnostic procedure on the basis of his clinical experience. Uveitis is a common complication of juvenile idiopathic arthritis depending on the subtype of arthritis. Patients with episcleritis rarely suffer from systemic inflammation, while inflammation is found in half of all cases of scleritis. Corneal ulceration should always be managed as an emergency case and, in addition to systemic medication, surgical intervention is often indicated. The degree of orbital or ocular involvement can be objectively monitored using modern imaging techniques. Medications against rheumatic inflammation may rarely result in ocular side effects, which should be detected early by the eye specialist.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Abb. 1
Abb. 2
Abb. 3
Abb. 4
Abb. 5
Abb. 6
Abb. 7
Abb. 8
Abb. 9
Abb. 10

Literatur

  1. Abu el-Asrar AM (1997) Central serous chorioretinopathy complicating systemic corticosteroid therapy. Eur J Ophthalmol 7: 297–300

    Google Scholar 

  2. Akpek EK, Thorne JE, Qazi FA et al. (2004) Evaluation of patients with scleritis for systemic disease. Ophthalmology 111: 501–506

    Article  PubMed  Google Scholar 

  3. Amm M, Nölle B (2002) Gore-Tex®-Patch-Aufnähung bei immunologisch bedingten Hornhautulzerationen. Klin Monatsbl Augenheilkd 219: 735–739

    Article  PubMed  Google Scholar 

  4. Becker MD, Bodaghi B, Holz FG et al. (2003) Diagnostische Vitrektomie bei Uveitis. Möglichkeiten der Molekularbiologie. Ophthalmologe 100: 796–801

    Article  PubMed  CAS  Google Scholar 

  5. Behrens A, Doyle JJ, Stern L et al. (2006) Dysfunctinal tear syndrome. A delphi approach to treatment recommendations. Cornea 25: 900–907

    Article  PubMed  Google Scholar 

  6. Biederer J, Schnabel A, Muhle C et al. (2004) Correlation between HRCT findings, pulmonary function tests and bronchoalveolar lavage cytology in interstitial lung disease associated with rheumatoid arthritis. Eur Radiol 14: 272–280

    Article  PubMed  CAS  Google Scholar 

  7. Bley TA, Uhl M, Markl M et al. (2007) Magnetresonanztomografie der Arteriitis temporalis Horton. Fortschr Röntgenstr 179: 703–711

    Article  CAS  Google Scholar 

  8. Both M, Aries PM, Müller-Hülsbeck S et al. (2006) Balloon angioplasty of arteries of the upper extremities in patients with extracranial giant-cell arteritis. Ann Rheum Dis 65: 1124–1130

    Article  PubMed  CAS  Google Scholar 

  9. Brignole F, Pisella PJ, Goldschild M et al. (2000) Flow cytometric analysis of inflammatory markers in conjunctival epithelial cells of patients with dry eyes. Invest Ophthalmol Vis Sci 41: 1356–1363

    PubMed  CAS  Google Scholar 

  10. Caldwell JR, Furst DE (1991) The efficacy and safety of low-dose corticosteroids for rheumatoid arthritis. Semin Arthritis Rheum 21: 1–11

    Article  PubMed  CAS  Google Scholar 

  11. Coles RS (1966) Steroid therapy in uveitis. Int Ophthalmol Clin Winter 6(4): 869–901

    CAS  Google Scholar 

  12. Cunningham MA, Edelman JL, Kaushal S (2008) Intravitreal steroids for macular edema: the past, the present, and the future. Surv Ophthalmol 53: 139–149

    Article  PubMed  Google Scholar 

  13. Dale DC, Petersdorf RG (1973) Corticosteroids and infectious diseases. Med Clin North Am 57: 1277–1287

    PubMed  CAS  Google Scholar 

  14. Dollfus H (1998) Eye involvement in children’s rheumatic diseases. Baillieres Clin Rheumatol 12: 309–328

    Article  PubMed  CAS  Google Scholar 

  15. El Afrit MA, Mazlout H, Trojet S et al. (2007) Cortisone glaucoma: epidemiological, clinical, and therapeutic study. J Fr Ophtalmol 30: 49–52

    Article  Google Scholar 

  16. Falcini F, Taccetti G, Trapani S et al. (1991) Growth retardation in juvenile chronic arthritis patients treated with steroids. Clin Exp Rheumatol Suppl 6: 37–40

    Google Scholar 

  17. Fox RI (1994) Systemic diseases associated with dry eye. Int Ophthalmol Clin 34: 71–87

    Article  PubMed  CAS  Google Scholar 

  18. Fujita M, Igarashi T, Kurai T et al. (2005) Correlation between dry eye and rheumatoid arthritis activity. Am J Ophthalmol 140: 808–813

    Article  PubMed  Google Scholar 

  19. Garbe E, LeLorier J, Boivin JF, Suissa S (1997) Risk of ocular hypertension or open-angle glaucoma in elderly patients on oral glucocorticosteroids. Lancet 350: 979–982

    Article  PubMed  CAS  Google Scholar 

  20. Galatoire O, Baudouin C, Pisella PJ, Brignole F (2003) Flow cytometry in impression cytology during keratoconjunctivitis sicca: effects of topical cyclosporin A on HLA DR expression. J Fr Ophtalmol. 26: 337–343

    Google Scholar 

  21. Galor A, Thorne JE (2007) Scleritis and peripheral ulcerative keratitis. Rheum Dis Clin North Am 33: 835–854

    Article  PubMed  Google Scholar 

  22. Gijtenbeek JM, van den Bent MJ, Vecht CJ (1999) Cyclosporine neurotoxicity: a review. J Neurol 87: 339–346

    Article  Google Scholar 

  23. Haerter G, Manfras BJ, de Jong-Hesse Y et al. (2004) Cytomegalovirus retinitis in a patient treated with anti-tumor necrosis factor alpha antibody therapy for rheumatoid arthritis. Clin Infect Dis 39: e88–94

    Article  PubMed  Google Scholar 

  24. Harper SL, Foster CS (1998) The ocular manifestations of rheumatoid disease. Int Ophthalmol Clin 38: 1–19

    Article  PubMed  CAS  Google Scholar 

  25. Hartmann M, Siebert S, Rohde S (2006) Kraniale Manifestation des Morbus Wegener: Aktueller Stand der Diagnostik. Fortschr Röntgenstr 178: 31–37

    Article  CAS  Google Scholar 

  26. Heiligenhaus A, Koch JM, Kemper D et al. (1994) Therapie von Benetzungsstörungen. Klin Monatsbl Augenheilkd 204: 162–168

    PubMed  CAS  Google Scholar 

  27. Henkind P, Gold DH (1973) Ocular manifestations of rheumatic disorders. Natural and iatrogenic. Rheumatology 4: 13–59

    PubMed  CAS  Google Scholar 

  28. Hick S, Demers PE, Brunette I et al. (2005) Amniotic membrane transplantation and fibrin glue in the management of corneal ulcers and perforations: a review of 33 cases. Cornea 24: 369–377

    Article  PubMed  Google Scholar 

  29. Hudde T, Neudorf U, Heiligenhaus A et al. (2007) Diagnostik bei Uveitis im Kindesalter: Welche Tests bei welcher Uveitis? Klin Monatsbl Augenheilkd 224: 494–499

    Article  PubMed  CAS  Google Scholar 

  30. Hylkema HA, Kijlstra A (1989) Circulating immune complexes in uveitis patients. Int Ophthalmol 13: 253–257

    Article  PubMed  CAS  Google Scholar 

  31. Jabs DA, Nussenblatt RB, Rosenbaum JT (2005) Standardization of uveitis nomenclature or reporting clinical data. Results of the First International Workshop. Am J Ophthalmol 140: 509–516

    Article  PubMed  Google Scholar 

  32. Jaffe GJ, Martin D, Callanan D et al. (2006) Fluocinolone Acetonide Uveitis Study Group. Fluocinolone acetonide implant (Retisert) for noninfectious posterior uveitis: thirty-four-week results of a multicenter randomized clinical study. Ophthalmology 113: 1020–1027 [Epub 2006 May 9]

    Article  PubMed  Google Scholar 

  33. James ER (2007) The etiology of steroid cataract. J Ocul Pharmacol Ther 23: 403–420

    Article  PubMed  CAS  Google Scholar 

  34. Kawai Y, Sumi M, Kitamori H et al. (2005) Diffusion-weighted MR microimaging of the lacrimal glands in patients with Sjögren’s syndrome. AJR Am J Roentgenol 184: 1320–1325

    PubMed  Google Scholar 

  35. Kadayifcilar S, Boyacioglu S, Kart H et al. (1999) Ocular complications with high dose interferon-alpha in chronic active hepatitis. Eye 13: 241–246

    PubMed  Google Scholar 

  36. Kasp E, Stanford MR, Brown E et al. (1992) Circulating immune complexes may play a regulatory and pathogenic role in experimental autoimmune uveoretinitis. Clin Exp Immunol 88: 307–312

    PubMed  CAS  Google Scholar 

  37. Kellner U, Kraus H, Foerster MH (2000) Multifocal ERG in chloroquine retinopathy: regional variance of retinal dysfunction. Graefe’s Arch Clin Exp Ophthalmol 238: 94–97

    Google Scholar 

  38. Kellner U (2006) Fundus autofluorescence and mfERG for early detection of retinal alterations in patients with chloroquine/hydroxychloroquine. Invest Ophthalmol Vis Sci 47: 3531–3538

    Article  PubMed  Google Scholar 

  39. Kotaniemi K, Arkela-Kautiainen M, Haapasaari J, Leirisalo-Repo M (2005) Uveitis in young adults with juvenile idiopathic arthritis: a clinical evaluation of 123 patients. Ann Rheum Dis 64: 871–874

    Article  PubMed  CAS  Google Scholar 

  40. Lai TY, Ngai JW, Chan WM, Lam DS (2006) Visual field and multifocal electroretinography and their correlations in patients on hydroxychloroquine therapy. Doc Ophthalmol 112: 177–187

    Article  PubMed  Google Scholar 

  41. Lane KA, Bilyk JR (2006) Preliminary study of positron emission tomography in the detection and management of orbital malignancy. Ophthal Plast Reconstr Surg 22: 361–365

    Article  PubMed  Google Scholar 

  42. Lamprecht P, Voswinkel J, Lilienthal T et al. (2002) Effectiveness of TNF-alpha blockade with infliximab in refractory Wegener’s granulomatosis. Rheumatol (Oxford) 41: 1303–1307

    Google Scholar 

  43. Levy GD, Munz SJ, Paschal J et al. (1997) Incidence of hydroxychloroquine retinopathy in 1,207 patients in a large multicenter outpatient practice. Arthritis Rheum 40: 1482–1486

    Article  PubMed  CAS  Google Scholar 

  44. Lyons JS, Severns ML (2007) Detection of early hydroxychloroquine retinal toxicity enhanced by ring ratio analysis of multifocal electroretinography. Am J Ophthalmol 143: 801–809

    Article  PubMed  CAS  Google Scholar 

  45. Malik R, Culinane AB, Tole DM, Cook SD (2006) Rheumatoid keratolysis: a series of 40 eyes. Eur J Ophthalmol 16: 791–797

    PubMed  CAS  Google Scholar 

  46. Manesis EK,Petrou C, Brouzas D, Hadziyannis S (1994) Optic tract neuropathy complicating low-dose interferon treatment. J Hepatol 21: 474–477

    Article  PubMed  CAS  Google Scholar 

  47. Mansour K, Leonhardt CJ, Kalk WW et al. (2007) Sjögren Workgroup. Lacrimal punctum occlusion in the treatment of severe keratoconjunctivitis Sicca caused by Sjögren syndrome: a uniocular evaluation. Cornea 26: 147–150

    Article  PubMed  Google Scholar 

  48. Margolis R (2008) Diagnostic vitrectomy for the diagnosis and management of posterior uveitis of unknown etiology. Curr Opin Ophthalmol 19: 218–224

    Article  PubMed  Google Scholar 

  49. Marmor MF, Carr RE, Easterbrook M (2002) Recommendations on screening for chloroquine and hydroxychloroquine retinopathy: a report by the American Academy of Ophthalmology. Ophthalmology 109: 1377–1382

    Article  PubMed  Google Scholar 

  50. McCluskey P, Powell RJ (2004) The eye in systemic inflammatory diseases. Lancet 364(9451): 2125–2133

    Article  PubMed  Google Scholar 

  51. Merimsky O, Nisiapeanu P, Loewenstein A (1992) Interferon-related cortical blindness. Cancer Chemother Pharmacol 29: 329–330

    Article  PubMed  CAS  Google Scholar 

  52. Messmer EM, Foster CS (1995) Destructive corneal and scleral disease associated with rheumatoid arthritis. Medical and surgical management. Cornea 14: 408–417

    Article  PubMed  CAS  Google Scholar 

  53. Muhle C, Reinhold-Keller E, Richter C et al. (1997) MRI of the nasal cavity, the paranasal sinuses and orbits in Wegener’s granulomatosis. Eur Radiol 7: 566–570

    Article  PubMed  CAS  Google Scholar 

  54. Nabili S, McCarey DW, Browne B, Capell HA (2002) A case of orbital myositis associated with rheumatoid arthritis. Ann Rheum Dis 61: 938–939

    Article  PubMed  CAS  Google Scholar 

  55. Nelson JD, Wright JC (1984) Conjunctival goblet cell densities in ocular surface disease. Arch Ophthalmol 102: 1049–1051

    PubMed  CAS  Google Scholar 

  56. Noble BA, Loh RS, MacLennan S et al. (2004) Comparison of autologous serum eye drops with conventional therapy in a randomised controlled crossover trial for ocular surface disease. Br J Ophthalmol 88: 647–652

    Article  PubMed  CAS  Google Scholar 

  57. Nölle B, Gross WL (1998) Augenmanifestationen bei systemischer Vaskulitis. Ophthalmologe 95: 266–285

    Article  Google Scholar 

  58. Nölle B (2001) Ophthalmologische Diagnostik bei systemischen Vaskulitiden. Z Rheumatol 60: 226–242

    Article  PubMed  Google Scholar 

  59. Norn MS (1970) Rose bengal vital staining. Acta Ophthalmol 48: 546–559

    Article  CAS  Google Scholar 

  60. Ollivier FJ, Gilger BC, Barrie KP et al. (2007) Proteinases of the cornea and preocular tear film. Vet Ophthalmol 10: 199–206

    Article  PubMed  CAS  Google Scholar 

  61. Parkin B, Chew JB, White VA et al. (2005) Lymphocytic infiltration and enlargement of the lacrimal glands: a new subtype of primary Sjögren’s syndrome? Ophthalmology 112: 2040–2047

    Article  PubMed  Google Scholar 

  62. Pfister RR, Murphy GE (1980) Corneal ulceration and perforation associated with Sjögren’s syndrome. Arch Ophthalmol 98: 89–94

    PubMed  CAS  Google Scholar 

  63. Porges Y, Blumen S, Fireman et al. (1998) Cyclosporine-induced optic neuropathy, ophthalmoplegia, and nystagmus in a patient with Crohn disease. Am J Ophthalmol 126: 607–609

    Article  PubMed  CAS  Google Scholar 

  64. Power WJ, Mullaney P, Farrell M, Collum LM (1993) Effect of topical cyclosporin A on conjunctival T cells in patients with secondary Sjogren’s syndrome. Cornea 12: 507–511

    Article  PubMed  CAS  Google Scholar 

  65. Prada J, Noelle B, Baatz H et al. (2003) Tumour necrosis factor alpha and interleukin 6 gene expression in keratocytes from patients with rheumatoid corneal ulcerations. Br J Ophthalmol 87: 548–550

    Article  PubMed  CAS  Google Scholar 

  66. Purvin VA (1995) Anterior ischemic optic neuropathy secondary to interferon alfa. Arch Ophthalmol 113: 1041–1044

    PubMed  CAS  Google Scholar 

  67. Reuter M, Schnabel A, Wesner F et al. (1998) Pulmonary Wegener’s granulomatosis: correlation between high-resolution CT findings and clinical scoring of disease activity. Chest 114: 500–506

    Article  PubMed  CAS  Google Scholar 

  68. Reuter M, Biederer J, Both M et al. (2003) Radiologie der primären systemischen Vaskulitiden. Fortschr Röntgenstr 175: 1184–1192

    Article  CAS  Google Scholar 

  69. Riley GP, Harrall RL, Watson PG et al. (1995) Collagenase (MMP-1) and TIMP-1 in destructive corneal disease associated with rheumatoid arthritis. Eye 9: 703–718

    PubMed  Google Scholar 

  70. Rodriguez-Padilla JA, Hedges TR 3rd, Monson B et al. (2007) High-speed ultra-high-resolution optical coherence tomography findings in hydroxychloroquine retinopathy. Arch Ophthalmol 125: 775–780

    Article  PubMed  Google Scholar 

  71. Rosenbaum JT (1990) An algorithm for the systemic evaluation of patients with uveitis: guidelines for the consultant. Semin Arthritis Rheum 19: 248–257

    Article  PubMed  CAS  Google Scholar 

  72. Rosenbaum JT, Wernick R (1990) The utility of routine screening of patients with uveitis for systemic lupus erythematodes or tuberculosis. A Bayesian analysis. Arch Ophthalmol 108: 1291–1293

    PubMed  CAS  Google Scholar 

  73. Schmidt R, Koderisch J, Krastel H et al. (1989) Sicca syndrome in patients with Wegener’s granulomatosis. Lancet 1(8643): 904–905

    Article  PubMed  CAS  Google Scholar 

  74. Seale JP, Compton MR (1986) Side-effects of corticosteroid agents. Med J Aust 144: 139–142

    PubMed  CAS  Google Scholar 

  75. Shinjo SK, Maia Júnior OO, Tizziani VA et al. (2007) Chloroquine-induced bull’s eye maculopathy in rheumatoid arthritis: related to disease duration? Clin Rheumatol 26: 1248–1253

    Article  PubMed  Google Scholar 

  76. Smith VA, Hoh HB, Easty DL (1999) Role of ocular matrix metalloproteinases in peripheral ulcerative keratitis. Br J Ophthalmol 83: 1376–1383

    PubMed  CAS  Google Scholar 

  77. Struffert T, Grunwald IQ, Mücke I, Reith W (2007) Interdisziplinäre Embolisation spontaner Karotis-Cavernosus-Fisteln Typ D nach Barrow über die Vena ophthalmica: klinische Langzeitergebnisse und kernspintomografische Befunde. Fortschr Röntgenstr 179: 401–405

    Article  CAS  Google Scholar 

  78. Tamesis RR, Rodriguez A, Christen WG et al. (1996) Systemic drug toxicity trends in immunosuppressive therapy of immune and inflammatory ocular disease. Ophthalmology 103: 768–775

    PubMed  CAS  Google Scholar 

  79. Thomas JW, Pflugfelder SC (2005) Therapy of progressive rheumatoid arthritis-associated corneal ulceration with infliximab. Cornea 24: 742–744

    Article  PubMed  Google Scholar 

  80. Thorne JE, Woreta F, Kedhar SR et al. (2007) Juvenile idiopathic arthritis-associated uveitis: incidence of ocular complications and visual acuity loss. Am J Ophthalmol 143: 840–846

    Article  PubMed  Google Scholar 

  81. Tripathi RC, Parapuram SK, Tripathi BJ et al. (1999) Corticosteroids and glaucoma risk. Drugs Aging 15: 439–450

    Article  PubMed  CAS  Google Scholar 

  82. Versura P, Frigato M, Mulé R et al. (2006) A proposal of new ocular items in Sjögren’s syndrome classification criteria. Clin Exp Rheumatol 24: 567–572

    PubMed  CAS  Google Scholar 

  83. Watson PG (1982) The nature and treatment of scleral inflammation. Trans Ophthalmol Soc UK 102: 257–264

    PubMed  Google Scholar 

  84. Whitcher JP (1987) Clinical diagnosis of the dry eye. Int Ophthalmol Clin 27: 7–24

    Article  PubMed  CAS  Google Scholar 

  85. Yilmaz S, Akarsu C (2006) Changes in cerebral and ocular hemodynamics in Behcet’s disease assessed by color-coded duplex sonography. Eur J Radiol 58: 102–109

    Article  PubMed  Google Scholar 

  86. Zaher SS, Sandinha T, Roberts F, Ramaesh K (2005) Herpes simplex keratitis misdiagnosed as rheumatoid arthritis-related peripheral ulcerative keratitis. Cornea 24: 1015–1017

    Article  PubMed  Google Scholar 

  87. Zeggini E, Packham J, Donn R et al. (2006) BSPAR Study Group. Association of HLA-DRB1*13 with susceptibility to uveitis in juvenile idiopathic arthritis in two independent data sets. Rheumatology (Oxford) 45: 972–974

    Google Scholar 

  88. (No author listed) (2007) The definition and classification of dry eye disease: report of the Definition and Classification Subcommittee of the International Dry Eye WorkShop (2007). Ocul Surf 5: 75–92

  89. (No author listed) (2007) The epidemiology of dry eye disease: Report of the epidemiology subcommittee of the international dry eye workshop (2007). Ocul Surf 5: 93–107

  90. (No author listed) (2007) Methodologies to diagnose and monitor dry eye disease: Report of the diagnosis methodology subcommittee of the international dry eye workshop (2007). Ocul Surf 5: 108–152

  91. (No authors listed) (2007) Management and therapy of dry eye disease: Report of the management and therapy subcommittee of the internatiol dry eye workshop (2007). Ocul Surf 5: 163–178

Download references

Interessenkonflikt

Der korrespondierende Autor gibt an, dass kein Interessenkonflikt besteht.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to B. Nölle.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Nölle, B., Both, M., Heller, M. et al. Typische Fragen aus der Rheumatologie an den Augenarzt und den kooperierenden Radiologen. Z. Rheumatol. 67, 360–371 (2008). https://doi.org/10.1007/s00393-008-0336-z

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00393-008-0336-z

Schlüsselwörter

Keywords

Navigation