Näkökenttäpuutos

Näkökenttäpuutos, also known as visual field defect, refers to a loss of vision in a specific area of the visual field. The visual field is the entire area that can be seen when the eye is fixed in one position. A defect means that part of this area is blind or has impaired vision. These defects can vary in size, shape, and location, and may be constant or fluctuating.

Causes of näkökenttäpuutos are diverse and can stem from problems in various parts of the visual pathway. This includes the eye itself, the optic nerve, the optic chiasm (where optic nerves cross), the optic tracts, the lateral geniculate nucleus, and the visual cortex in the brain. Common conditions leading to visual field defects include glaucoma, which damages the optic nerve, stroke, which can affect the visual cortex or optic pathways, brain tumors, multiple sclerosis, and retinal diseases like macular degeneration or detachment. Trauma to the head or eye can also cause these deficits.

Symptoms of näkökenttäpuutos can be subtle or very noticeable. Some individuals may not be aware of a defect until it significantly impacts their daily activities, such as bumping into objects on one side, difficulty reading, or problems with depth perception. Others might experience blurred vision, blind spots, or a feeling of something obstructing their vision. The specific symptoms depend on the location and extent of the damage. Diagnosis typically involves a visual field test, also known as perimetry, which maps out the visual field by presenting light spots and asking the patient to indicate when they are seen. Treatment depends entirely on the underlying cause and aims to manage the condition or, in some cases, improve or recover the lost vision.