Glaucoma Can Go Years Undetected Due to Few Noticeable Symptoms

Jonathan Eisengart, MD, an ophthalmologist at Cleveland Clinic, spoke with The American Journal of Managed Care® about what glaucoma is as well as what signs or symptoms patients can look to when they go to the eye doctor.

This transcript has been lightly edited for clarity.

Transcript

What is glaucoma and how can it be detected?

So a lot of people think that glaucoma is a disease in which they have high eye pressure, and that's actually not true. Glaucoma is a disease of the optic nerve. So the optic nerve is your vision nerve. It's the nerve or the cable that connects your eye to your brain. So in glaucoma, we see a very slow and progressive, meaning worsening, atrophy of the optic nerve. And what I mean by that is the optic nerve basically, very slowly dies off bit by bit in glaucoma. We don't really know exactly why this happens. We do know that high pressure, and this is where pressure comes in, high pressure is certainly a risk factor for developing glaucoma, and if your eye pressure is very high, you're almost certain to develop glaucoma. But it is also possible to have glaucoma with normal eye pressure, and probably a third, at least a third of my patients have glaucoma with normal eye pressure. So glaucoma really is about a very specific type of optic nerve degeneration that we see or atrophy.

There's a few important characteristics about glaucoma and how the optic nerve dies away. First is that it takes very, very long for people with glaucoma to develop any noticeable vision loss. So glaucoma can be going on for years and years undetected. And that's really very key for the public to know, is that we want to screen for it and find it during those years where it's not causing any symptoms. Most people think, "Oh, I'm going to lose my peripheral vision with glaucoma." And they kind of self test out to the sides if they can see it. Interestingly, glaucoma really, hardly ever affects the vision way out to the side. Most people with glaucoma actually start to lose vision on the nose side of their peripheral vision. So for instance, with my right eye here, if I cover my left people with glaucoma would might start to notice. I shouldn't say notice, but we can measure areas of vision loss on the nose side of the vision, and because both eyes are seeing in that area, especially if it's happening in only 1 side, you don't notice it because the other side compensates or covers it up. As glaucoma gets worse and worse, people might lose a lot of the top half of their vision or the bottom half of their vision, but seldom way out to the sides.

There [are] other types of optic nerve degeneration besides glaucoma, and as I said, 1 thing unique about glaucoma is they maintain the sharpness of their vision for a long time. Other types of optic nerve disease cause a vision to become blurry very early on. People with glaucoma don't get blurry vision or dim vision until very late in the disease. Also, people with glaucoma maintain good color vision for a long time, whereas other types of optic nerve degeneration or diseases can cause color vision to be washed out or inaccurate. People with glaucoma maintain good color vision for a long time. But [those are] some of the differences between the glaucoma type of optic nerve atrophy and other types that we may see.