Glaucoma is a vision-threatening disease with two basic types – open-angle and closed-angle.

Open-angle glaucoma is the most common and can go undetected for years with gradual decline in vision. The primary symptoms are gradual loss of peripheral vision and then tunnel vision in the advanced stages of the disease.

Closed-angle glaucoma is rarer but occurs more rapidly with much more severe symptoms, including eye pain, nausea, vomiting, blurred vision and a halo effect around lights.

Both open- and closed-angle glaucoma can be effectively treated with vision preserved, especially if closed-angle cases are detected early.