Glaucoma is a disease of the eye. It is caused by damage to the part of the optic nerve that is inside the eye. It is one of the leading causes of irreversible blindness in the world.
Follow the link to know – What is optic nerve?
Follow the link to understand the basic structure of the eye
What causes Glaucoma
Many factors lead to the development of glaucoma. But the most important risk factor is the intraocular pressure. An increase in the intraocular pressure, when not controlled in time, can develop glaucoma. Although, there are cases of glaucoma where nerve damage happens even with normal intraocular pressure.
Many theories of mechanisms of development of glaucoma had been put forward. One of them is the mechanical theory.
Follow the link to know what is intraocular pressure or eye pressure
Normally– The fluid (aqueous humour) inside the eye is continuously produced and continuously drained from the eye.
So what happens if there is overproduction of the aqueous or more commonly, block in the drainage?
– The fluid inside the eye increases, which increases the pressure inside the eye
Imagine a plastic ball filled with water. It is stable as the amount of water inside the ball is the same as the volume of the ball. What happens if you try to inject more water inside the ball (Figure 2)? The pressure inside the ball increases. This exerts mechanical stress on the wall of the plastic ball. Similar pressure is exerted on the optic nerve fibers in the eyeball. If this pressure is there for a long amount of time, the nerve cells start to die, which is an irreversible process. This irreversible damage to the nerve cells (retinal ganglion cells) is Glaucoma.
Treatment for Glaucoma
Unfortunately, there is no cure for the disease. But if diagnosed early and managed properly, the disease progression can be slowed down drastically and blindness can be prevented. That is the reason glaucoma screening is important- to diagnose the disease early.