Many people report the experience of seeing lights during meditation practice. These lights can vary from small, sparkling, comet-like flashes to glowing balls to a transcendent vision of spiritual light some refer to as the "great white light." Different spiritual traditions and meditation methods place different meanings on these lights, so what meaning they have, if any, depends on what the individual thinks about them.
Buddhist meditation methods sometimes involve visualizing or imagining a holy light, but this is different from actually seeing lights. The purpose of light visualization in Buddhist meditation is to apply mindfulness or focused mental presence to circumstances in which the mind would ordinarily wander, such as when doing the dishes. Despite the use of such visualization methods, having visions of actual lights is not emphasized or given any particular symbolic importance in Buddhist meditation. Buddhist meditation is focused on impermanence, or the understanding that everything is subject to change. This impermanence would apply to any lights seen in meditation as much as to anything else.
Kundalini meditation traditions include the concept of the "great white light," a vision of a heavenly light that enfolds the meditator and imparts some type of spiritual understanding. Kundalini meditation also can result in seeing other lights, such as sparkling comet shapes, glowing balls or kaleidoscope images. These lights can be interpreted in various ways, such as manifestations of "prana," or spiritual energy, or even as actual spirits. This depends, of course, on the personal beliefs of the meditator.
Meditation instructor Swami Rama has written that many meditators assume they are having profound spiritual experiences when they are merely experiencing hallucinations created by their own subconscious. Swami Rama also has advised that the meditator should never focus on having a specific experience, such as a vision of lights, even though some meditators will spontaneously see lights when they practice. The important thing to remember is that seeing something like a light is not the purpose of meditation, but merely a side effect that happens to some people. Not seeing lights does not mean that the meditation isn't working.
According to Swami Sivananda, another meditation instructor, the lights that sometimes appear during meditation are indications that the "chakras" or spiritual centers in the human body have been activated. Although Swami Sivananda does interpret the vision of lights as having some degree of spiritual significance, he warns that it does not represent actual enlightenment and should never be used as an excuse to set yourself up as some kind of guru. Swami Sivananda considers the vision of lights during meditation as an indication that some level of progress has been made, and that the meditator should remain focused on the meditation itself while ignoring the lights.