What are the symptoms of glaucoma?

Often there are no obvious symptoms of glaucoma in the early stages of open angle glaucoma. Your eye may look perfectly normal, with no pain and your eyesight may seem to be unchanged. Even damage to the optic nerve may go unnoticed at first because only the very edge of the field of vision is affected at first. Also, if one eye is affected more than the other, the better eye may compensate for sight loss in the more damaged eye.

Glaucoma can progress so slowly that you may not notice your eyesight has been affected until you have lost a lot of sight, leaving only the central field of vision - the blindness called "tunnel" vision. (See example of “tunnel” vision below).

Sudden or acute glaucoma can be quite painful, with the affected eye red. There may be also nausea and vomiting. This requires urgent or emergency treatment to relieve the pain and preserve sight loss.

Example of the effect of Glaucoma on vision