Trataka is a yogic purification (shatkarma) - also known as candle gazing- that enhances our physical eyes and 3rd eye vision.
Trataka is a practice where the gaze is fixed on an object (for example a candle wick) for some time and then that object is visualized clearly with the eyes closed, as an inner image at the eyebrow center. It trains us in the ability to focus and defocus. Trataka is sad to develop the 3rd eye, the seat of intuition & psychic powers. The eyeball movements that are done as a preparation to the trataka practice, are beneficial to the physical eye.