Glaucoma is the result of damage to the optic nerve. As this nerve slowly becomes damaged, blind spots may expand into the patient’s visual field. For reasons that most doctors do not fully understand, this nerve damage is usually related to the increased intraocular pressure in the eye. Optic nerve damage can also happen with normal intraocular pressures. This condition is called normal tension glaucoma. Increased sensitivity to high or fluctuating intraocular pressure can damage parts of the optic nerve. The optic nerve is comprised of 1.2 million nerve fibers. Loss of these nerve fibers slowly over time can affect the peripheral vision and in advanced cases can affect the central vision too.
There are two major glaucoma types. These are:
- Primary open-angle glaucoma
- Angle-closure glaucoma
Primary open-angle glaucoma
This is the more common type of glaucoma. It occurs slowly. The eye does not drain the fluid in the front part of the eye as it should – it has been described as a drain that is clogged. Because of this, the pressure in the eye builds and this begins to damage the optic nerve. This type is painless and causes no changes in vision in the beginning. There are some individuals that can have an optic nerve that is actually sensitive to eye pressure that is normal. This means their peril of getting glaucoma is much higher than other. Regular exams of the eye are vital to find early signs of damage to the optic nerves.
This is also referred to as “narrow-angle glaucoma” or “closed-angle glaucoma”. This kind develops when the iris is very close to the drainage angle inside the eye. The iris can block the drainage angle. This is much like having a piece of paper sliding over the drain of a sink. When the angle of drainage gets totally blocked, eye pressure rises quickly. This is called an “acute attack”. It is a true emergency of the eye and needs to be seen by an ophthalmologist immediately or blindness could occur.
Signs of an acute angle-closure glaucoma attack include:
- Vision is blurry suddenly
- Eye pain that is severe
- Rings that are rainbow colored or haloes around lights
Angle-closure glaucoma can cause blindness if not treated right away.