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Progressive bifocal chorioretinal atrophy, also known for its abbreviations PBCRA or CRAPB, [1] is a rare, slowly progressive, autosomal dominant syndrome characterized by relatively large-sized atrophic hole-shaped lesions in the macular and nasal retina, myopia, low visual acuity, and nystagmus.
Optic nerve sheath meningiomas (ONSM) are rare benign tumors of the optic nerve. 60–70% of cases occur in middle age females, and is more common in older adults (mean age 44.7 years). It is also seen in children, but this is rare. The tumors grow from cells that surround the optic nerve, and as the tumor grows, it compresses the optic nerve.
Optic nerve melanocytoma does not usually produce symptoms or grow. If they slowly grow, optic nerve melanocytoma can produce afferent pupillary defects (30%), subretinal fluid (10%), and an enlarged blind spot (75%). On fundoscopic exam, the optic disc may be swollen, atrophic, or even normal. [1] Central retinal vein occlusion may occur.
Presumed ocular histoplasmosis syndrome (POHS) is a syndrome affecting the eye, which is characterized by peripheral atrophic chorioretinal scars, atrophy or scarring adjacent to the optic disc and maculopathy. The loss of vision in POHS is caused by choroidal neovascularization.
A nervous system tumor is a tumor that arises within the nervous system, either the central nervous system (CNS) or the peripheral nervous system (PNS). [1] [2] Nervous system primary tumors include various types of brain tumor and spinal tumors, such as gliomas, and meningiomas (of the CNS), and schwannomas (of the PNS) and can be either benign or malignant.
A nerve sheath tumor is a type of tumor of the nervous system (nervous system neoplasm) which is made up primarily of the myelin surrounding nerves. Nerve sheath tumors can be benign or malignant , and may affect both the peripheral and central nervous systems .
After several years, the occurring optic nerve atrophy results in artifactual looping of the axons into the atrophic nerve. This looping was initially described by Wilbrand, who studied subjects with severe optic nerve atrophy after enucleation, and who then appears to have exaggerated the importance of this looping in later drawings. [ 5 ]
The optic nerve can be damaged when exposed to direct or indirect injury. Direct optic nerve injuries are caused by trauma to the head or orbit that crosses normal tissue planes and disrupts the anatomy and function of the optic nerve; e.g., a bullet or forceps that physically injures the optic nerve.