Johtosilmä

Johtosilmä is a Finnish term that translates literally to "conductor eye" or "lead eye." It refers to a specific type of visual distortion or optical illusion experienced by some individuals. This phenomenon is characterized by the perception of a persistent, often circular, bright spot or flash of light in one's field of vision. It is not a physical object but rather a subjective visual experience.

The cause of johtosilmä is not fully understood and can vary. It is often associated with conditions affecting the retina, such as posterior vitreous detachment, where the vitreous humor pulls away from the retina. Other potential triggers include mechanical stress on the eye, bright light exposure, or even certain types of eye medications. While the experience can be startling, it is typically benign and temporary, often resolving on its own. However, if the phenomenon is persistent, accompanied by other visual disturbances like floaters or flashes, or causes significant distress, it is advisable to consult an ophthalmologist to rule out any underlying eye conditions. The term is primarily used in informal contexts within Finland.