Primary Open Angle Glaucoma

Primary open angle glaucoma is the most common form of glaucoma. It happens when the eye’s drainage canals become clogged over time.

The inner eye pressure (also called intraocular pressure or IOP) rises because the correct amount of fluid can’t drain out of the eye. With open-angle glaucoma, the entrances to the drainage canals are clear and should be working correctly. The clogging problem occurs further inside the drainage canals, similar to a clogged pipe below the drain in a sink.


Glaucoma is an eye disease that gradually steals vision. There are typically no early warning signs or painful symptoms of open-angle glaucoma. It develops slowly and sometimes without noticeable sight loss for many years.

Most people who have open-angle glaucoma feel fine and do not notice a change in their vision at first because the initial loss of vision is in peripheral vision. Visual acuity or sharpness of vision is maintained until late in the disease.

By the time you are aware of vision loss, the disease is usually quite advanced. Without proper treatment, glaucoma can lead to blindness. The good news is that with regular eye exams, early detection, and treatment, you can preserve your vision.

Eye Exams

Because open-angle glaucoma has few warning signs or symptoms before damage has occurred, it is important to see our optometrists for regular eye examinations. If glaucoma is detected during an eye exam our optometrists can refer you to a glaucoma specialist who can prescribe a preventative treatment to help protect your vision.

Optic Nerve Damage

In open-angle glaucoma, the angle in your eye where the iris meets the cornea is as wide and open as it should be, but the eye’s drainage canals become clogged over time, causing an increase in internal eye pressure and subsequent damage to the optic nerve.

Treatment of Primary Open Angle Glaucoma

There are many treatment options available for open angle glaucoma. The earlier treatment is started the better the outcomes tend to be and the less affect glaucoma will have on vision. Many treatments are available on the NHS. Your glaucoma specialists will provide you with a treatment plan appropriate to your eye and glaucoma.

Traditionally eye drops are the treatment of choice for this type of glaucoma. There are many drops on the market that can be used to lower the pressure within the eye or increase the drainage from the eye successfully. However, recent studies are suggesting that laser treatments such as ALT and SLT may become first choice treatments in future. If eye drops are not effective laser treatments and surgery may be suggested.