Asking for steps to acquire a tomometer

 I need specific instructions on how to get a tonometer for home use. Perhaps those of you who have gone through the process can help me.

Question 1. I understand that I need a prescription from my eye doctor. On the prescription, does the model name of tonometer (such as AT555 or 7CR) need to be specified, or it can be just generally described, like "any auto non-contact tonometer"?

Question 2. Once I get the prescription, do I go around to place an order myself or my doctor needs to make the purchase on my behalf? The posts I read from this forum seem to indicate both.