The effect of age on normal human optic nerve fiber number and diameter.

In one optic nerve from each of 19 persons, the authors determined the number of axons, the distribution of fiber diameter, and the total neural area. The mean fiber count was 693,316, the mean neural area was 5.17 mm2, and the mean axonal fiber diameter was 0.96 microns. No significant decline in fiber number or neural area with increasing age was found. The authors found a large variability of axonal number among their patients. This variability would have obscured any small effect of aging. Linear regression analysis of the effect of age on mean axonal diameter yielded a slight negative slope (P less than 0.01), suggesting a redistribution of fiber diameter. This could occur from axonal shrinkage, from preferential large fiber loss, or from the technical features of tissue acquisition and analysis. The authors suspect that the explanation is a selective loss of large nerve fibers.

[1]  S. Drance,et al.  Neuroretinal rim area in early glaucoma. , 1985, American journal of ophthalmology.

[2]  S. Drance,et al.  The area of the neuroretinal rim of the optic nerve in normal eyes. , 1987, American journal of ophthalmology.

[3]  D. Minckler.  The organization of nerve fiber bundles in the primate optic nerve head. , 1980, Archives of ophthalmology.

[4]  R. Massof,et al.  Morphologic changes in the lamina cribrosa correlated with neural loss in open-angle glaucoma. , 1983, American journal of ophthalmology.

[5]  J W Griffin,et al.  Control of axonal caliber by neurofilament transport , 1984, The Journal of cell biology.

[6]  J Katz,et al.  Asymmetry and variation in the normal hill of vision. , 1986, Archives of ophthalmology.

[7]  W R Green,et al.  Chronic human glaucoma causing selectively greater loss of large optic nerve fibers. , 1988, Ophthalmology.

[8]  G. Dunkelberger,et al.  The number and diameter distribution of axons in the monkey optic nerve. , 1986, Investigative ophthalmology & visual science.

[9]  C. Miller,et al.  Optic-nerve degeneration in Alzheimer's disease. , 1986, The New England journal of medicine.

[10]  A. Mccormick,et al.  Aging of the optic nerve. , 1980, Archives of ophthalmology.

[11]  W. Green,et al.  Optic nerve damage in human glaucoma. III. Quantitative correlation of nerve fiber loss and visual field defect in glaucoma, ischemic neuropathy, papilledema, and toxic neuropathy. , 1982, Archives of ophthalmology.

[12]  M Schulzer,et al.  The effect of age on the nerve fiber population of the human optic nerve. , 1984, American journal of ophthalmology.

[13]  G. Dunkelberger,et al.  Chronic glaucoma selectively damages large optic nerve fibers. , 1987, Investigative ophthalmology & visual science.

[14]  J. Provis,et al.  Human fetal optic nerve: Overproduction and elimination of retinal axons during development , 1985, The Journal of comparative neurology.

[15]  P. Dyck,et al.  Decreased axon caliber and neurofilaments in hereditary motor and sensory neuropathy, Type I , 1984, Annals of neurology.