gms | German Medical Science

102. Jahrestagung der DOG

Deutsche Ophthalmologische Gesellschaft e. V.

23. bis 26.09.2004, Berlin

The ocular surface disorders: pathology and pathogenesis

Meeting Abstract

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Evidenzbasierte Medizin - Anspruch und Wirklichkeit. 102. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft. Berlin, 23.-26.09.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dogSA.10.10

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Veröffentlicht: 22. September 2004

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The normal ocular surface is covered by conjunctival, limbal and corneal epithelial cells that maintain its integrity with a stable preocular tear film. Corneal stem cells reside at the corneo- scleral limbus. The microenvironment of the limbus is considered to be important in maintaining the turnover of stem cells. Under certain conditions, however, the limbal stem cells may be partially or totally depleted because of reduction or absence of tears and owing to pathologic process involving the innevation. These conditions produce different degrees of stem cells deficiency, resulting in abnormalities of the corneal surface. Limbal stem cell deficiency can be complicated with conjunctivalization and vascularization of the cornea, chronic inflammation, recurrent and persistent epithelial defects up to erosion, ulcer and xerophtalmia. These signs are termed "ocular surface degeneration". The more common conditions known to produce severe ocular surface disease include: chemical and thermal injuries, use of contact lens, limbal surgery, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, neurotrophic keratopathy, corneal intraepithelial neoplasia, several microbial infections, limbitis, multiple surgeries or cryotherapies at the limbal region. Less common causes include aniridia, congenital eritrocheratodermia and keratitis associated with hereditary multiple endocrine deficiencies. Diagnosis of limbal stem cell deficiency make use of slit-lamp examination with fluorescein stain, tear function's test, impression citology, which can detect cellular phenotype. Confocal microscope consents to effect an exact and reliable microscopy. Early diagnosis and appropriate medical therapies (topical corticosteroids and lubrificants) permit us to correct the underlying cause, to suppress the untoward inflammation, or to improve tissue healing so that they are essential in the management of corneal epithelial defects and ulcers. When persistent ulcerative epithelial defect develops, we often resort to such surgical therapies. A variety of techniques have been reported for limbal stem cell transplantation. Although all techniques used in stem cell transplantation are similar in principle, the source of donor stem cells can vary. First of all the objectives of stem cell transplantation are principally to restore phenotypic corneal epithelium to the corneal surface, to promote the limbus barrier function, to improve surface lubrification. In unilateral disease this can be accomplished successfully by conjunctival limbal autograft; however, in bilateral disease allograft transplantation is the only option available. The stem cells can be expanded ex vivo on a processed human amniotic membrane and transplanted back to ocular surface with stem cell deficiency without the need of immunosuppression. Amniotic membrane transplantation combined with limbal transplantation has been used in patients with diffuse limbal stem cell deficiency.