Trāṭaka (Sanskrit n. त्राटक trāṭaka, tratak, trataka: “to look, or to gaze”) is the practice of staring at some external object. This fixed gazing is a method of meditation which involves concentrating on a single point such as a small object, black dot or candle flame. It is used in yogaas a way of strengthening the eyes, improving of memory, development of good concentration ,strong willpower and stimulating the ājňā chakra.
Make the eyes clear and bright.
Balances the nervous system, relieving tension, anxiety, depression and insomnia.
Trataka may be practice on a regular base, daily or it may of be use for periods of time to work on stabilizing the mind.
The best time of practice is after asana and pranayama, and before meditation.
In case of eye ailments such as eyestrain, myopia, astigmatism and even the early symptoms of cataract or epileptics should not practice on a flame, should choose a totally steady object or black dot.