näkökentällä

Näkökentällä is a Finnish term that translates to "in the field of vision" or "visual field." It refers to the entire area that can be seen by the eye when it is fixed in one position. The visual field is not uniform; it is most sensitive in the central area, known as the fovea, which is responsible for sharp, detailed vision. As the visual field extends towards the periphery, vision becomes less detailed and more sensitive to movement.

The extent of an individual's visual field is typically measured in degrees. A person with normal binocular vision has a horizontal visual field of about 190 degrees and a vertical visual field of about 135 degrees. The visual field is divided into several parts, including the central visual field, which is crucial for tasks like reading and recognizing faces, and the peripheral visual field, which plays a role in spatial awareness and detecting threats.

Various medical conditions can affect the visual field, leading to blind spots (scotomas) or a general narrowing of vision. These conditions can include glaucoma, cataracts, macular degeneration, and neurological disorders affecting the visual pathways in the brain. Ophthalmologists and optometrists use specialized tests, such as visual field perimetry, to assess the integrity of a person's visual field and diagnose potential problems. Understanding the concept of näkökentällä is fundamental in ophthalmology and vision science for diagnosing and managing a wide range of visual impairments.