To start with, it is important to realise that glaucoma is not one single disease. There are many types of glaucoma, each of which may present or start off with different symptoms/feelings in the eye.
Having said that, the most common type of glaucoma is what we call primary open angle glaucoma, or POAG. This answer will deal only with POAG.
With POAG, pressure in the eyeball slowly increases over a period of time, and this high eye pressure gradually damages nerve cells in the optic nerve.
The high eye pressure from POAG typically causes no symptoms. There is no ache, no pain or even the slightest irritation. And because optic nerve damage is also gradual, there are no visual symptoms in the early stages. When the glaucoma becomes advanced, patients become aware of areas in their vision which they cannot see, or what may be called blind spots. If the condition is not treated, the blind spots enlarge until eventually blindness results.
As POAG causes no symptoms in the early stages, it is sometimes called the thief of sight. It is one of the reasons why regular eye checks are a good idea for older folk, or even younger ones who have a strong family history or who otherwise have a higher risk of developing the condition. If the condition is detected early, medication to lower the eye pressure can stop visual deterioration and stabilise the condition. Sometimes, if medication is not enough to lower eye pressure, then surgery can be considered as a second line.
Each patient should clarify the diagnosis and treatment plan with their own doctor, who will know the specific diagnosis and situation best.
