Though it sounds horrible it is a proven treatment and is done regularly. There are appropriate measures taken to make it as comfortable as possible for the patient and fearing a tried and true medical procedure is not worth going blind over.
I've had glaucoma for many years. It runs in my family and in the past several of my relatives went blind because of it. but now it can be treated and controlled. Yes, the medication is expensive and is a rip off when one can just smoke pot to lower the pressure on the optic nerve.
But the drug companies would not make megabucks then! Why is your case so different?