Dr. Bindiya Hapani, Senior Consultant Ophthalmologist, Dr Agarwal’s Eye Hospital, said that there are two major types of glaucoma: open angle glaucoma, and close angle glaucoma. Open angle glaucoma is the most common form of glaucoma. It accounts for at least 90% of all glaucoma cases. It progresses very slowly and the patient may not feel any loss of vision until it affects the central vision. This results in permanent damage if the patient does not get an eye check-up.