You will need three items to get started:
1. glass eye cups (quantity two) [here]
3. triphala powder [here]
I put about 1/4 tsp of the triphala powder in a tea bag and steep in about a half a cup of boiling water. I let it sit for about 5 minutes.
Then I cool it in the refrigerator because the cold tea feels good to my eyes. If you wish, you can use room temperature or even mildly warm tea.
I'll give you a couple sentences related to Ayurvedic perspective regarding temperature. Cool tea will help reduce Pitta. If your eyes tend to be red, irritated or you sometimes feel a burning sensation in your eyes, then reducing Pitta might be the strategy for you.
Warm tea might help balance Vata and/or Kapha. Kapha is traditionally said to be responsible for intraocular hypertension. In reality, balancing Vata, Pitta and Kapha requires sophisticated knowledge. But if you simply pay attention to what feels good for your eyes, chances are you will be on the right track in terms of selecting the appropriate temperature for your triphala eye wash. Don't make it a big deal.
Put the tea in the glass eye cups. Put the eye cups on your eyes and rest for about 2 to 3 minutes, blinking frequently.
Watch out because the triphala tea will stain anything it touches, including your shirt or the carpet. I just use an old towel to make sure I don't get the tea on anything.
For most people, including those with healthy eyes and those with glaucoma or any other eye disease, this is something you could do every day. It is like brushing your teeth. Washing your eyes with triphala is considered part of the regular daily hygiene routine in Ayurveda.
It is probably not a good idea to do this if you have had a trabeculectomy (or have any wounds or open injuries on your eyes).
Optional: I put a pinch of high grade sodium ascorbate in each eye cup with the triphala tea. I don't recommend this for most people. And if you do use the ascorbate, be consistent with it.