Electron-microscopic identification of pseudoexfoliation material in extrabulbar tissue
U. Schlotzer-Schrehardt, M. Kuchle and G. O. Naumann
Department of Ophthalmology, University of Erlangen-Nurnberg, Federal Republic of Germany.
The structure and distribution of pseudoexfoliation material in extrabulbar
tissues from five eyes with typical unilateral intraocular
pseudoexfoliation syndrome and two intraocularly unaffected fellow eyes
were examined by transmission electron microscopy. In all seven eyes,
unevenly distributed pseudoexfoliation aggregates were found in limbal
conjunctivae, extraocular rectus and oblique muscles, orbital
connective-tissue septa, and the walls of the posterior ciliary arteries,
vortex veins, and central retinal vessels passing through the optic nerve
sheaths. Typical pseudoexfoliation fibers occurred in close association
with connective-tissue components, especially elastic fibers; a moderate
predisposition of pseudoexfoliation clumps to accumulate around blood
vessels was observed. The findings of pseudoexfoliation material in similar
extrabulbar locations in intraocularly uninvolved fellow eyes indicates
that pseudoexfoliation fiber formation outside the globe precedes its
intraocular manifestation. The intermingling of pseudoexfoliation fibers,
microfibrils, and elastic and collagen fibers suggests that
pseudoexfoliation fiber formation might result from a disordered synthesis
and/or assembly of connective-tissue microfibrils.
