Pathophysiologic changes in the optic nerves of eyes with primary open angle and pseudoexfoliation glaucoma.
OBJECTIVE
To determine whether differences in the optic nerve occur in eyes with primary versus secondary open-angle glaucoma.


METHODS
Optic nerves obtained at autopsy from 36 eyes with primary open-angle glaucoma (POAG) and 15 with pseudoexfoliation glaucoma (PEXG) were studied quantitatively and qualitatively. Axon counts, fibrosis, capillary number and density, and arteriosclerotic changes were assessed in the postlaminar optic nerve and compared to normal age-matched autopsy eyes. Changes in composition of extracellular matrix components were evaluated by immunohistochemistry and electron microscopy.


RESULTS
Marked differences were found between POAG and PEXG. Axon loss in eyes with POAG but not in PEXG was associated with increasing connective tissue in the septa and surrounding the central retinal vessels, including increased amounts of type IV and VI collagen. The total number of capillaries decreased with the loss of axons in both POAG and PEXG. POAG nerves, however, had a decrease in the density of capillaries, whereas in PEXG the capillary density did not change with axon loss. Arteriosclerotic changes were more common in glaucomatous eyes than in age-matched control eyes.


CONCLUSIONS
The difference in morphology of the optic nerves between POAG and PEXG indicates that in eyes with POAG, elevated IOP cannot be the only pathogenetic factor in glaucomatous optic neuropathy. Additional factors, inducing fibrosis and loss of capillaries, seem to be involved. Such additional factors may also contribute to the clinical finding in POAG that nerves can become damaged without elevation of intraocular pressure.
Gottanka
Johannes
J
Department of Anatomy II, University of Erlangen-Nürnberg, Germany.
Kuhlmann
Alexander
A
Scholz
Michael
M
Johnson
Douglas H
DH
Lütjen-Drecoll
Elke
E
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D001369:Axons / Q000378:metabolism / Q000473:pathology*; D002452:Cell Count; D017889:Exfoliation Syndrome / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005260:Female; D005355:Fibrosis; D005902:Glaucoma, Open-Angle / Q000150:complications / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007150:Immunohistochemistry; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000098:blood supply / Q000378:metabolism / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000503:physiopathology*
D016326:Extracellular Matrix Proteins