Glaucoma can be classified in different ways.
It can be primary glaucoma – which means that the disease is not associated with any other conditions or it can be secondary glaucoma – which is associated with other eye conditions.
The most common classification is open-angle and closed-angle glaucoma.
What is “Angle” in the eye?
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It is approximately the angle made by the cornea and the iris at their roots. It is also the place where most of the drainage of the aqueous humour (fluid inside the eye) occurs.
Open-angle Glaucoma
It is the disease when the angle of the eye is normal but the drainage is blocked because of several reasons. It is like a clog in the drain or the drain is faulty. This increases the fluid inside the eye, which then increases the pressure (intraocular pressure).
- Primary – due to structural changes in the drainage system, which the person is born with. But there are no associated eye conditions.
- Secondary – due to an associated eye condition.
Angle-closure glaucoma
It is a disease where the angle becomes narrow or closed due to several reasons and the drainage fluid gets limited. This results in its accumulation and therefore, increased pressure. There is a condition called acute angle-closure glaucoma which is an emergency. The patient presents with severe headache, eye pain, eye redness, nausea, vomiting, etc. Some eyes are predisposed to this condition which can be diagnosed during glaucoma screening. If you have a family history of angle-closure glaucoma, you may be at risk of a similar disease.
- Primary – due to structural changes in the anterior segment, which the person is born with. But there are no associated eye conditions
- Secondary – due to an associated eye condition.