OCT [Optical Coherence Tomography] is a key test for glaucoma diagnosis. OCT looks at your retinal nerve fiber for indicators of glaucoma process. Visual fields testing is important. But it is a late sign of glaucoma, when many nerve cells in retina die.

Increased eye pressure, intraocular pressure, is not the only test for glaucoma. Dr. Anton Titov, MD. It's several tests looking at the back of the eye with the ophthalmoscope. Glaucoma diagnosis depends also measuring visual fields. Dr. Francesca Cordeiro, MD. Yes. All the diagnostic tests taken together can establish the diagnosis that a patient has a silent glaucoma. Yes, because it is silent, you need objective ways of measuring whether the eye disease is present or not. Dr. Anton Titov, MD. One of the things also that we've become increasingly aware of. Even though the gold standard for glaucoma diagnosis is the visual field testing. There has to be quite a lot of your eye nerve cells lost before the visual field is affected. So, one of the things that has developed over the last few years is this. It is the ability to see progression of visual field loss. Dr. Francesca Cordeiro, MD. We can do OCT [Optical Coherence Tomography] measurements. Optical Coherence Tomography looks at your retinal nerve fiber. Changes in optic nerve are an indicator that you have glaucoma eye disease. So, seeing if a peripheral field vision changes are progressing over the time. Exactly. That underscores the importance of having the visual field test done. Even if a person has normal vision and no complaints about vision. It is crucial to establish the vision acuity baseline. Yes, that's absolutely true. But one of the things that has been coming through is our ability to image the back of the eye. This has improved over the last 10 years. One of the big advances is the use of Optical Coherence Tomography [OCT]. Optical Coherence Tomography is almost doing a non-histological optical section of the eye. The retina consists of lots of different layers of nerve cells. They're all specialized. But they're all damaged differently in the glaucoma eye disease. Dr. Francesca Cordeiro, MD. In glaucoma the top layer consists the retinal ganglion cells. We know that that top layer thins sometimes. It does so even before you have any changes on your visual field test. You can look for changes of that decline in the thickness of that retinal layer. Dr. Anton Titov, MD. That in itself is an indicator that your visual field is going to be lost in the future. That is a sign of glaucoma.