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Central retinal artery occlusion: CRAO is characterized by painless, acute vision loss in one eye. [11] Central retinal vein occlusion: CRVO causes sudden, painless vision loss that can be mild to severe. [12] Branch retinal vein occlusion: sudden painless vision loss or visual field defect are the main symptom of BRVO. [13]
Visual field-tubular vision Visual field-central scotoma. Lesions involving the whole optic nerve cause complete blindness on the affected side, that means damage at the right optic nerve causes complete loss of vision in the right eye. [3] Optic neuritis involving external fibers of the optic nerve causes tunnel vision. [4]
A clue to the cause of intoxication is the presence of oxalate crystals in the urine. Like methanol intoxication, treatment is ethanol consumption. Ethambutol, a drug commonly used to treat tuberculosis, is notorious for causing toxic optic neuropathy. People with vision loss from ethambutol toxicity lose vision in both eyes equally.
NAION is the most common cause of sudden optic nerve-related vision loss, affecting more than 10,000 Americans every year, often bilaterally. No clinically effective treatments exist, largely because little is known about its pathophysiology, and there are few histopathological studies of the acute condition.
There are many diseases known to cause ocular or visual changes. Diabetes , for example, is the leading cause of new cases of blindness in those aged 20–74, with ocular manifestations such as diabetic retinopathy and macular edema affecting up to 80% of those who have had the disease for 15 years or more.
Vision loss in toxic and nutritional optic neuropathy is bilateral, symmetric, painless, gradual, and progressive. Dyschromatopsia, a change in color vision, is often the first symptom. Some patients notice that certain colors, particularly red, are less bright or vivid; others have a general loss of color perception.
Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception.In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficulties with normal daily tasks, including reading and walking. [6]
AI is generally considered separate from presbyopia, but mechanically both conditions represent a difficulty engaging the near vision system (accommodation) to see near objects clearly. Presbyopia is physiological insufficiency of accommodation due to age related changes in lens (decreased elasticity and increased hardness) and ciliary muscle ...