How is glaucoma treated?
You might simply have eye drops to use every day. He might give you a laser treatment, with or without eye drops, to open the trabecular meshwork and reduce the IOP by speeding up fluid drainage. Each glaucoma case is different and Thomas will discuss treatment options with you so you understand why one or another would be best for you.
Thomas will not automatically give you eye drops. He may do a laser treatment first, or may advise a combination of both eye drops and laser treatment.
Selective Laser Trabeculoplasty (SLT)
Behind the cornea is a fluid, called aqueous humour that is continually produced and continually drains out of the eye. When leaving the eye, it flows through a system of tiny channels called the trabecular meshwork. If there is any blockage in these channels, the fluid cannot drain out at a speed to match its production speed. That causes a build-up of IOP.
The SLT treatment focuses a laser on the trabecular meshwork cells that contain pigment called melanin. The pigment absorbs the light and heat and the cells go through a reaction called photothermolysis – they are broken down. That stimulates the meshwork to heal and in the process the channels become wider. Cells with no melanin are not affected.
This is not a new treatment, but it is now done with a new laser that is more effective than the older one. It is effective at about ten times less heat and light, which means the treatment, can be repeated if necessary. It may need repeating after about five years, depending on your age, type of glaucoma, and treatment response.
Glaucoma – Trabeculectomy Valves
Thomas also offers the ExPRESS® mini shunt to improve outflow of aqueous fluid. It is a tiny implant with a valve that redirects the flow from the inside to the outside of the eyeball. It is inserted as part of a surgical procedure called a Trabeculectomy. It is often effective for people who do not get good enough results from SLT or eye drops.
How does glaucoma cause blindness?
The high pressure inside the eye puts pressure on the optic disc (the front part of the optic nerve) leading to damage and permanent death of optic nerve fibres. The optic nerve fibres converge from all over the retina, forming the optic nerve. This large nerve leaves the eye to carry image data to the brain’s vision centre at the back of the head.
With each damaged fibre, the optic nerve carries less vision data to the brain. The first fibres damaged are those on the outside of the nerve bundle, which give us our peripheral vision. Over the years, unchecked high IOP will continue damaging fibres. Unless something is done to reduce the pressure in your eye, you will continue to lose more peripheral vision.