Sudden Loss of vision/ transient loss/ Field defects
Transient loss/Sudden loss of vision
Transient visual loss is a frequently encountered complaint that, in most cases, has an identifiable cause. The loss of vision may be monocular or bilateral and may last from seconds to hours. Episodes are usually ischemic in origin. Causes of ischemic transient visual loss include cerebrovascular ischemia, retinal arteriolar emboli, and amaurosis fugax syndrome.
Sudden visual loss is a common complaint with variable presentations among patients of different ages. Some patients describe their symptoms as a gradually descending gray-black curtain or as blurring, fogging, or dimming of vision. Symptoms usually last a few minutes but can persist for hours. Variation in frequency ranges from a single episode to many episodes per day; recurrences may continue for years but more frequently occur over seconds to hours.
Visual field defects are a loss of part of the normal area of vision in one or both eyes. Visual field defects take different forms, ranging from loss of areas at the outer edges of vision (peripheral vision) or small blind spots to loss of most of the area that you normally see (the visual field). Visual field defects may be caused by damage to the light-sensitive retina at the back of the eye; the optic nerve, along which nerve signals are carried from the retina to the brain; or the parts of the brain involved with vision.