(February 29, 2008 - Insidermedicine) Welcome to Insidermedicine's If I Had, where we get a chance to ask an expert what they would do if they had a medical condition.
On a recent trip to Boston, we caught up with Dr. Joan Miller, MD, who is Chair of the Department of Ophthalmology at Harvard Medical School, and Chief of Ophthalmology at the Massachusetts Eye and Ear Infirmary. Dr. Miller is a retina specialist, and an active researcher in ocular neovascularization in macular degeneration and diabetic retinopathy.
We asked Dr. Miller what she would do if she had macular degeneration.
Dr. Miller: People with macular degeneration usually find that out as part of a routine eye exam and really have no symptoms that lead them there, but they will be told by their eye physician at that point that they should monitor their vision and, in particular, look for signs of distortion. So, looking at something that should be straight and finding out that now it looks wavy. They may be given something called an Amsler Grid, which looks like square graph paper, which again is to look for distortion. And before we go through all of the workup from the point of noticing a change in vision, it’s important to understand, you know, what the macula is. I usually describe the retina as the film that lines the back of the eye, like film in the camera, and that’s where the light lands and sends the images to your brain. The macula is a very small part, but it’s the part that’s designed especially for high resolution. So it’s the part we use for reading, driving, recognizing faces, and all that good stuff. Lots of things affect the macula but age-related macular degeneration is one of the most common, and it affects people generally over the age of 50.
The risk factors for it are very similar as the risk factors for heart disease, so smoking is really a biggy, it’s the most consistent. And then things like high blood pressure or high cholesterol. There also appear to be genes involved, although it’s not something where there’s one gene and you get the disease – it’s much more complex than that. There’s two types of macular degeneration – you’ll hear “dry” and “wet”, and the dry is much more common, and you can have dry macular degeneration and never have any trouble. If you do develop vision problems with the dry, generally it’s very slow and you may just notice that you need a little more light to read with, you’ll have a little trouble going from a bright lit environment into a darker environment. And then on rare occasions, people can lose substantial central vision even with the dry form. The dry, though, can become wet and with the wet form, the abnormal blood vessels grow in and under the retina in the macula, leak fluid and bleed and scar in that area, and the vision can drop suddenly and quite severely. That’s what we watch for with patients, so with patients with the dry form, we really try to have them look and see if they have a vision change. So once someone notices a change, I said it’s really distortion, so looking at this Amsler Grid and seeing that the squares look bent. Looking at bathroom tiles is another good trick to use. It doesn’t have to be grid paper. But once someone notices distortion, they really should get seen and evaluated within about a week, and what happens when you go to the eye physician for evaluation is that they will check your vision. Vision is the most important measurement for us – it’s like blood pressure. So they’ll check the vision and they’ll put dilating drops in your eye and have you sit out in the waiting room for a few minutes, and then bring you back in to re-examine the retina. And to do that we use magnifying lenses and a microscope to look at the surface of the macula, and what we’re looking for there is fluid or blood or signs of this wet form of macular degeneration.
Usually we’ll do some other testing at that point if we’re suspicious that the wet form has started, and the testing that we do is divided into two groups – one is something called OCT, or Optical Coherence Tomography. It’s a relatively new technique but it’s used pretty commonly, and it shows fluid within and under the retina and is a really good marker for this wet macular degeneration. We also use angiography and that’s really an older, more standard diagnostic tool. For angiography we inject fluorescent dyes into the vein of the arm and because we can look into the eye, you can actually see the dye is traveling through the blood vessels within the eye. That allows us to see the leaky, abnormal blood vessels. Once we’ve done these tests and if they do indeed now show that there is wet macular degeneration, there are treatments for this. And that area has really changed dramatically in the last few years. The most common treatment that we use now is a form of drug that blocks the growth factors that make the blood vessels grow and leak, and that drug is actually injected into the eye, so it’s injected through the white coat of the eye. Really small needle, sounds bad, but patients really tolerate it quite well.
There’s several drugs that are out there – ranibizumab was tested in large clinical trials and showed in those trials that 95% of people avoided moderate vision loss, and that’s quite dramatic. But even more remarkable was that about a third of patients actually had dramatic improvement in vision with treatment, and that really changed the field for patients and for physicians. That was the first time we had a treatment where they could really have an improvement in vision. Before bevacizumab was approved and available for use, which happened just in the summer of 2006, other physicians led by Phil Rosenfeld being one of them started injecting Avastin, which is another anti-VEGF [vascular endothelial growth factor] drug and that also seems to be quite effective, and is much cheaper. There will be a head-to-head comparison trial of those two drugs. But those are the most common treatments that we give. They do need to be repeated. The studies actually looked at monthly injections. Doctors really tried to balance that, looking at vision and response, and then the OCT test as well.
Sometimes doctors will also suggest a couple other treatments – one of them is injecting steroids into the eye, which may also be combined, and then also something called photodynamic therapy, or Visudyne, which is a drug and laser combination. So your eye doctor should lead you through that discussion of all the available treatments and make the suggestions. Certainly ask questions about the risks and benefits of all of those, but we really have a lot more to offer patients than we did in the past.