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Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteri
Such lesions give rise to extensive astrocyte loss, which may occur in part in the absence of any other tissue injury, such as demyelination or axonal degeneration (lesion type 5). Finally, lesions with a variable degree of astrocyte clasmatodendrosis are found, which show plaque-like primary demyelination that is associated with ...
Complications after cataract surgery are relatively uncommon. Posterior vitreous detachment (PVD) may occur but does not directly threaten vision. [23] Some people develop a posterior capsular opacification (PCO), also called an after-cataract. This may compromise visual acuity, and can usually be safely and painlessly corrected using a laser.
Cyanopsia is most commonly reported in older adults after cataract surgery, where symptoms typically subside within a few days to weeks as the eyes adapt to the synthetic lens. In younger adults, cyanopsia is often caused by medications like sildenafil, with symptoms disappearing once the drug's effects wear off.
Visual outcome after cataract surgery was close to conformity with WHO guidelines in Buenos Aires, where more than 80% of post-surgery eyes had visual acuity of 6/18 (20/60) or better, but ranged between 60% and 79% in most of the other regions, and was less than 60% in Guatemala and Peru. [129]
Wallerian degeneration occurs after axonal injury in both the peripheral nervous system (PNS) and central nervous system (CNS). It occurs in the section of the axon distal to the site of injury and usually begins within 24–36 hours of a lesion. Prior to degeneration, the distal section of the axon tends to remain electrically excitable.
In its traditional manifestation, chronic inflammatory demyelinating polyneuropathy is characterized by symmetric, progressive limb weakness and sensory loss, which typically starts in the legs. Patients report having trouble getting out of a chair, walking, climbing stairs, and falling.
Even within a fascicle, demyelination does not affect nerves uniformly. For example, in the early stages, demyelination can be seen at the edge of fascicles near the periphery of the nerve, and in later stages the demyelination is diffusely seen within the entirety of a fasicle. [5] [16] Damage to the myelin sheath of nerves is a nerve injury.