Glaucoma which is an eye disease is covered mostly under medical health insurance that you have.
A vision health insurance plan usually does not cover any medical costs due to Glaucoma Treatment.
If you have other health insurance such as private health insurance or any other major health insurance for medical treatments then the Glaucoma treatments and other medical things for Glaucoma would be covered by those health or medical insurance companies.
Glaucoma is also covered by Obamacare and the Affordable Care Act.
So if you have that health care coverage then you can use it to pay for the treatment of the Glaucoma Eye Disease.