Glaucoma is an eye condition where increased pressure inside the eye causes damage to the optic nerve, which connects the eye to the brain. If untreated, Glaucoma can lead to loss of vision and blind spots. Symptoms of glaucoma Glaucoma does not usually cause any symptoms to begin but over many years it begins to affect your peripheral vision. Often a patient only finds out they have glaucoma during a routine eye test. Noticeable symptoms can include blurry vision, or seeing rainbow-coloured circles around bright lights. Glaucoma will usually affect both eyes although may be worse in 1 eye. Very occasionally, glaucoma can develop suddenly and cause: intense eye pain nausea and vomiting a red eye a headache tenderness around the eyes seeing rings around lights blurred vision Types of glaucoma Most common - primary open angle glaucoma, develops slowly over many years and is caused by the drainage channels in the eye becoming gradually clogged over time. Other types of glaucoma include: acute angle closure glaucoma – an uncommon type caused by the drainage in the eye becoming suddenly blocked, which can raise the pressure inside the eye very quickly secondary glaucoma – caused by an underlying eye condition, such as inflammation of the eye (uveitis) or by another co-morbidity such as diabetes mellitus childhood glaucoma (congenital glaucoma) – a rare type that occurs in very young children, caused by an abnormality of the eye