Glaucoma FAQ

1. What is glaucoma?

Glaucoma is a word that has been used by many people to mean many different things.  As a consequence, there is a great deal of confusion about what it is.  Originally glaucoma referred to a condition in which an eye become rock hard and painful and the patient usually lost vision.  We now know that this was probably Angle Closure Glaucoma [link].   In these patients it was noticed that the optic nerve had a characteristic appearance after the attack.  Later, patients were recognized who lost vision, and whose optic nerves developed a similar appearance, but whom never experienced the episode of very high pressure.  These are what we now know as Open Angle Glaucoma [link].  Over the years, as we have come to understand that high pressure can cause the vision loss of glaucoma, conditions where the pressure is high or even conditions where the pressure might become high have been called glaucoma.  Finally, it has been seen that some patients lose vision without ever having high pressures and these are called glaucoma as well.

When thinking of glaucoma it is advisable to think of two separate things: the damage the occurs to the optic nerve which seems to be related to pressure and those things that may cause the pressure to rise high enough to cause damage to the optic nerve.  When either of these conditions is present treatment may be advisable.

2.  Are there different kinds of glaucoma?

Glaucoma has been divided up by many different criteria at different times.  Probably the most useful way to divide it is into Open Angle Glaucoma [link] and Narrow Angle or Angle Closure Glaucoma [link].  Within each of these types of glaucoma there are multiple subtypes.  However, the treatments for various Open Angle Glaucomas tend to be similar and the treatments for various Narrow Angle Glaucomas tend to be similar, but different than the treatments for Open Angle Glaucomas.

3.  My doctor says that my “pressures are high.”  What does that mean?

The eye is like a ball.  It must have a certain amount of pressure inside it to keep it inflated.  If the pressure is too low it doesn’t work well.   However, if the pressure is too high, it may cause damage to the vision.  This is what we call glaucoma. However, different people can tolerate different levels of pressure.  Just because the pressure is higher than average does not mean that damage will occur.

4.  My doctor says my nerves are “cupped.”  What does that mean?

The optic nerves have a central depressed area.  In photographs this tends to look like a pale circle inside the more pink circle of the optic nerve.  If glaucoma damage occurs this depressed area, or “cup” becomes larger.  Many normal people have large cups, but when the cups are larger than average we worry that they used to be smaller and have become larger, indicating glaucoma damage.