Artikel
Structural changes of the sclera-connective tissue in keratoconus and pellucid marginal corneal degeneration
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Autoren
Veröffentlicht: | 22. September 2004 |
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Gliederung
Text
Objective
Genetically conditioned progressing cornea ectasia (keratoconus, pellucid marginal degeneration) characterized by changes elastic facilities cornea at the expense of biochemical, morphological disturbances. It is known that elastic facilities of the corneal and sclera mutually connected. The aim is to investigate the specularities of the sclera connective tissue at these diseases electron microscopically.
Methods
Transmission electron microscopy were performed in 5 scleral discs in diameter 2 mm removed by posterior sclerectomy in 4 patients (4 eyes) with keratoconus III-IV degree (classification by Amsler) and 1 patient (1 eye) with pellucid marginal corneal degeneration. One patient had Down's syndrome.
Results
There were established pathological changes of collagenic structures of the sclera connective tissue by the type observed in high myopia - peculiarly changed collagenic complexes (splitting into subfibrills, their granular decomposition as well as formation of periodic "notches" fibrils, "stepping" structurs). Primary structural changes analogic to the above mentioned revealed by myopia in anterior section of sclera that says about their primary character. In Down's syndrome the eye with keratoconus had mainly typical dystrophy of the sclera connective tissue caused by inflam-matory processes, with may be masking primary changes of collagenic structures.
Conclusions
The scleral tissue in keratoconus and pellucid marginal corneal degeneration characterized by pathological changes with are morphological basis of its mechanical facilities disturbances. Revealed disturbances of the sclera collagenic structures leading to changes of its biomechanics properties can be one of the factors of the genetically caused progressing corneal ectasia.