A: Glaucoma signs and symptoms vary depending on the disease type. Unfortunately, the most common form, primary open-angle glaucoma, develops without warning signs. Typically, sufferers only become aware of the condition once sight loss has already occurred. Acute-angle closure glaucoma develops more rapidly and so is easier to detect. Symptoms of this glaucoma type include blurred vision, seeing halos or coloured rings around lights, and painful, red eyes. The hidden nature of glaucoma highlights why it is so important to receive regular examinations if you are high-risk for the disease.