An ultrastructural study of the corpora amylacea of the optic nerve head and retina

We studied corpora amylacea in the optic nerve heads and retinas of four human eyes with increased intraocular pressure by light and electron microscopy. Ultrastructurally they consisted of a mass of filamentous tangle discretely bordered by normal or abnormal axoplasm within an axonal swelling. We found neurotubules, mitochondria, and the accumulation of dense bodies in the axoplasm surrounding the filamentous tangle. We noted ultrastructural similarities between corpora amylacea and cytoid bodies, swollen axons with transport block, and experimentally induced neurofibrillary tangles. We concluded that corpora amylacea are intracellular organelles found in axonal swellings and are not glial in origin, as previously believed. There is a possible relationship between corpora amylacea and disturbance of axoplasmic transport.