Cheryl Martin (Host): Glaucoma is often referred to as the silent thief of sight. We're observing Glaucoma Awareness Month, and we'll learn more about this condition and the advantages of opting for minimally invasive glaucoma surgery with Dr. Jennifer Coben, a dedicated ophthalmologist and glaucoma specialist at Guthrie Specialty Eye Care. This is Medical Minds, Conversations with Guthrie Experts, a podcast from the Guthrie Clinic. I'm Cheryl Martin. Dr. Coben, as an expert in glaucoma, give us a brief explanation of the condition and tell us why Glaucoma Awareness Month is so important.

Dr Jennifer Coben: So, glaucoma is a condition that damages the optic nerve, which is basically the cable that connects the eyeball to the brain. And the optic nerve relays the signal or the visual stimuli to the brain. And so, it is brain tissue. And so, glaucoma is caused by a set of genetic and environmental factors. But basically, the underlying issue is that the pressure is too high in the eye relative to the optic nerve. And so, the optic nerve gets damaged and unfortunately because the optic nerve is brain tissue, any damage that occurs at the level of the optic nerve is permanent and results in vision loss. So, that is glaucoma in a nutshell. But glaucoma is important to recognize, be aware of, because it is the number one cause of irreversible vision loss worldwide and it is the number two cause of vision loss after cataract, which is treatable. Glaucoma is treatable, but we want to get ahead of any damage because, as I said, any damage that occurs is irreversible.

Host: I mentioned that it's often referred to as the silent thief of sight due to its asymptomatic nature. Elaborate on this and tell us how early detection can play a crucial role in managing this condition.

Dr Jennifer Coben: Glaucoma, unfortunately, is often asymptomatic in that there are no signs or symptoms. There's often no pain at all until the very late stages. Typical glaucoma folks begin to lose vision on the sides, on the periphery of the vision. And that progresses until it involves the very center. Glaucoma damage isn't often detected until its very late stages. And for that reason, it's important to get screenings, especially more earlier intervals, if there is a family history or other risk factors.

Host: And when you say screenings, does that mean when you go to your ophthalmologist for a regular appointment, you should ask if there's a special screening for glaucoma?

Dr Jennifer Coben: Yes. So, screening for glaucoma involves checking eye pressure and also looking at the optic nerve. In some cases, those two findings would also indicate further testing like visual field testing as well. And most optometrists and ophthalmologists are comfortable screening for glaucoma. But if you're going to get your glasses checked and the eye pressure's not checked, you're not getting a full screening for glaucoma. And so, it's important to have your eye pressure checked and relay to your eye doctor if there is a family history of glaucoma that would warrant further testing.

Host: So really, the patient should be proactive and ask for this.

Dr Jennifer Coben: Well, it certainly doesn't hurt to inquire with your family members. With eye conditions, it can be tough to know. Often family members may not share that they have lost vision in one eye. But if you're certainly aware of a family history, that puts you at higher risk for developing glaucoma. And so if you're aware of that, it's definitely important to get screening, but glaucoma can occur even in the absence of family history or a known family history. So, it's important for everyone to get screened for glaucoma at their eye visits with your eye doctor on a yearly basis.

Host: Now, minimally invasive glaucoma surgery or MIGS seems to be a game-changer in treating glaucoma patients. Give us an overview of MIGS and how it differs from traditional glaucoma surgeries.

Dr Jennifer Coben: Sure. So, as a glaucoma specialist, that involves doing an additional training in glaucoma surgery, traditional glaucoma surgery. And when we think of traditional glaucoma surgery, we're thinking about placing large stents into the eye or creating trap doors in the scleral tissue to create drainage outflow in the eye. And these are big surgeries with also some definite bigger risks than a standard cataract surgery, if you will. So, traditional glaucoma surgery is quite involved and requires close follow up and monitoring with a dedicated glaucoma specialist. And most glaucoma surgeries in the traditional sense are performed when there is definite vision loss or no eyedrops are being tolerated by the patients or the eyedrops simply aren't working and we're seeing field loss, we're seeing that the patient on testing is losing vision. And so, we act through these bigger surgeries to prevent vision loss. And so, these surgeries have more risk, but also work well to help lower pressure.

However, not everyone with glaucoma is experiencing field loss. You can have damage on the nerve that we see with other testing where we're screening the optic nerve and we're seeing damage or thinning on the nerve over time. This is a precursor for field loss. So if we're seeing evidence of optic nerve damage, and the patient requires treatment, but not maybe a severe loss that would require bigger surgery, then we may consider minimally invasive glaucoma surgery, because this surgery by nature is less invasive, exposes the patient to less risk, is safe, and can help stabilize pressures so that secondary surgeries, bigger surgeries like I mentioned before, may not be necessary.

Minimally invasive glaucoma surgery is typically done at the time of cataract surgery, but not always. But basically, when we take the cataract out, we're able to turn the patient's head. And using the microscope and a special lens, we're able to visualize the patient's natural drainage tissue and enhance outflow naturally using stents or a system of catheterizing the drain. I tell patients it's kind of like a Roto-Rooter technique. It's all basically plumbing on a much smaller level. So, minimally invasive glaucoma surgery has far less risk, is very well tolerated, and often takes seconds to just a minute or so to perform, whereas traditional glaucoma surgery can take 30 minutes to an hour or more to perform. There are more stitches involved, there's more bleeding, there's risk of high or low eye pressure in the after period of surgery, and the goals are much more aggressive to aggressively lower eye pressure.

Minimally invasive glaucoma surgery, however, what we're trying to do is prevent progression on fields as well, but our goals are not as aggressive. So, maybe we want the patient to continue on their eyedrop regimen as it is now, maybe get them off of an eyedrop or prevent us from having to add future eyedrops or do more invasive surgery down the line. So, that's what's so exciting about minimally invasive glaucoma surgery. We're able to treat the patient's glaucoma at the time of often cataract surgery to help prevent these other procedures or other medications or interventions from having to be performed later on.

Host: Anything else about how this procedure improves the quality of life for people living with glaucoma. Midway

Dr Jennifer Coben: Certainly. With minimally invasive glaucoma surgery, in many patients, as I said, we're able to get them off of one or more of their eyedrops or prevent them from having to start more eyedrops. Now, eyedrops are great, but many of them contain preservatives. They have to be dosed multiple times a day. And often, patients experience redness and irritation. Certainly, bigger glaucoma surgeries can be quite involved. And so, these other interventions, while they can work well, eye drops, bigger surgeries, do come with some disadvantages. So, by being able to treat the glaucoma at the level of the natural drain, at the time of cataract surgery, and more often now, we are able to do them as stand alone procedures, meaning we're not doing them with cataract surgery, we're able to get into the drain naturally through an operation. By being able to treat that space, it's less invasive, there's less cutting, less downtime for the patient. Most patients are able to go back to work relatively soon, like the next day, for instance, in most patients. And so, quality of life is enhanced by just reduction in further treatments, elimination of certain drops that were on, and stabilization of the fields, of course, which is important.

Host: Now, for those considering MIGS, what should they know about the risks? And you mentioned the recovery time already, but what about the success rates?

Dr Jennifer Coben: Success rates are quite high. When we're looking at the data and the trials, cataract surgery alone, thankfully, it helps lower eye pressure. But when we do these other techniques, we're able to enhance eye pressure lowering. So for instance, the Hydrus microstent, trials looking at five-year data, their HORIZON trial, showed reduction in visual field progression. That was even at five years. Seventy-eight percent of patients who had the Hydrus with cataract surgery, for instance, were drop-free at two years. So, it's big numbers. And along the same lines we see with other procedures such as the Omni, iStent, we see reductions in pressure, stabilization of fields far and away more than just cataract surgery alone. So, the benefits are definitely notable. And we've seen them in clinical trials. We're continuing to study the benefits.

As far as risk or added risk to the patients, we are working in a space the natural drain filters out to the circulatory system. So when we're working in a natural drain, we will expect and want to see some egress of red blood cells or see a little bit of bleeding inside of the eye. It's often on a microscopic level. But at first, in the early postoperative period, we can see some microscopic red blood cells on exam. This isn't something that a patient typically sees, they don't see bleeding in their eye, but it can lead to some more visual blur in the early days after a cataract surgery, for instance, or in the early days after the surgery. But thankfully, the red blood cells circulate out. And then, we're left with lower eye pressures.

Host: So, what advancements do you foresee in the field of glaucoma treatment, particularly with MIGs?

Dr Jennifer Coben: I think we're going to just continue to see more minimally invasive approaches come to the forefront. We're going to see different spaces in the eye used to help lower pressure. And additionally, we're seeing more basically drug-eluting devices that we can place inside of the eye to help deliver medication as well.

So, I think there's a lot of exciting new technology coming down the pipeline, simply because there's such a demand for it. There's such a burden for glaucoma in this country and worldwide. And our traditional methods expose the patient to higher risk. So, I think we're moving towards a space where we're looking at earlier intervention to prevent these other procedures from having to be performed that are more invasive.

Host: As we wrap up our conversation during Glaucoma Awareness Month, are there some preventative measures or lifestyle changes that could help mitigate the risk of developing glaucoma?

Dr Jennifer Coben: In general, glaucoma is a set genetic and environmental factors that come to play. So, it's important to maintain a healthy diet. We have seen that diabetes is a risk factor for glaucoma. High blood pressure, long-term, is not directly related to eye pressure, but is related to the perfusion of the optic nerve. So, staying overall healthy, eating a healthy diet is helpful for the eyes. Cardiovascular exercise is great for eye pressure in general. But most significant glaucoma is related to genetic factors and the eye's shape and size, which we cannot control. And for that reason, it's important to maintain screenings and contact with an eye doctor on a yearly basis so that any glaucoma that's present is detected early and treated.

Host: Dr. Jennifer Coben, thanks for sharing your insights on glaucoma and the treatments available. Great information.

Dr Jennifer Coben: My pleasure. Thanks for having me.

Host: For more information, just visit guthrie.org. And if you found this podcast helpful, please share it on your social media and check out the full podcast library for other topics of interest to you.

This is Medical Minds Conversations with Guthrie Experts, a podcast from the Guthrie Clinic. Thanks for listening.