Any case my first teacher to yoga Prabhaji in Borivli also taught me trataka. I saw that she did not teach this to everyone -- she was the first to teach me jal neti, meditation (ajapa japa which is similar to TM) and that was wonderful because it set me off on meditation as a serious part of my practice right from the start. I would do 20 minutes of meditation daily, come rain or shine. Which is why I could do vipassana three times in a small village town of Alandi, with no frills or favors, and in the heat of a Maharastrian summer, and survive it to feel I have still a long way to go.
Without meditation as a daily practice, yoga is not really much.
But those days what helped my meditation practice was trataka. I would do that too, and was fascinated at how it helped my body become still. I was restless before that. My left eye would start watering and I would stare at the red bindi resolutely till it did.. It is a puzzle why my left eye always waters -- happens even with reflexology massages, or when someone does reiki for me!
Its been a while since I practiced trataka, and I am feeling prodded to return to the practice after reading a translation of the Geranda Samhita by Swami Niranjanananda Saraswati of the Bihar school of yoga.
In a manner of speaking,when I do Muay Thai, my sir always exhorts me to keep my eye steady on the imagined pair of eyes -- the opponent's --when I punch or kick. This is very akin to trataka. He also says I must do other accessory conditioning, like push-up, without blinking my eyes (hey, trataka). So, it goes