Topical Treatment for Open-Angle Glaucoma
Sahar Bedrood, MD, PhD: What is your preferred first-line class of drugs for IOP lowering?
Joseph F. Panarelli, MD: So, whenever I have a patient who’s newly diagnosed with glaucoma, my first-line treatment is typically a prostaglandin analogue, and I like to start with this medication class for various reasons. First it is proven that these drugs provide superior efficacy. Second, it is a medicine that is often well tolerated, and third, I think my compliance is best because these medicines are often dosed only once daily. So, for those reasons, I tend to start with either latanoprost or one of the branded medicines such as either Travatan (travoprost) or Lumigan (bimatoprost).
I think there’s been recent evidence in the literature to suggest that it might be even better for our patients to begin with laser therapy. So laser trabeculoplasty involves applying energy to the trabecular meshwork to stimulate inflammation, and the inflammatory changes that take place inside the eye allow for better outflow through the drainage canal. And I think there’s been good evidence from the LiGHT study that this effect can last up to 3 years. So, for some of our patients, I think it’s worth having a discussion with them whether they prefer to start topical therapy or whether they would like to proceed with laser trabeculoplasty.
Dr. Bedrood: When do you add another class of medication to your glaucoma patients?
Dr. Panarelli: So, for any of my patients with glaucoma, it’s a big decision for me to add another medication. I always tell patients this is not a short course of antibiotics that I’m putting them on — I’m putting them on life-long treatment. So, for me, when I add a second agent, often I have to be sure that the patient is either progressing or at a pressure I deem them likely to progress. If that is the case, I often will actually jump to a combination agent.
When I trained, I came out of Fellowship more of a purist and I began one medicine at a time. However, I find that for a lot of my patients who I think are progressing fast, the ones that really need good IOP control and strict IOP control, I prefer to jump to a combination agent because I think it gets me to my goal of treatment much, much more quickly.
And, again, if I’ve begun with a prostaglandin analogue, I may actually go to laser trabeculoplasty as my second option. And I think for me that’s actually where I find laser to be the most beneficial. I prefer to use it as a second-line treatment modality. There are some new medicines that are out there that we’ll talk about later on in this segment, but I think some of them actually do work nicely as second-line agents. And I think for all of us as glaucoma specialists, we’re trying to figure out where these new medicines fit into our surgical armamentarium. But I think the truth is we don’t fully know yet.
Dr. Bedrood: Is the treatment regimen a percent reduction in IOP for you or is it a target IOP?
Dr. Panarelli: I think that’s always a challenging question, and I think it depends on who your mentor was. Some of us tend to look at the IOP and want to set a target. Some of us look at a percent IOP reduction. I’m going to be honest: One of the main reasons I don’t set a target IOP is that it is often difficult to have a patient follow up who’s just outside the target, but you tell them they’re fine and they sit there and say, “Well, Doc, you said my target was 14 mm Hg but today I’m 17 mm Hg. Why are we not making changes?” So I’m a little bit hesitant to actually write a number down because I think then it often sets expectations for the patient that are not always realistic. I always tell patients, it’s not always the exact number that we’re treating, we’re treating the disease.
So, for me, I do tend to set a percentage reduction when I have a newly diagnosed patient. It’s often somewhere between 30% to 35%. There is good literature to support that, such as from the CIGTS study, which showed that for patients with newly diagnosed glaucoma, we really should strive to get about a 35% or more reduction in pressure for our patients who have newly diagnosed glaucoma.
Dr. Bedrood: How have treatment preferences changed over the years?
Dr. Panarelli: I think preferences have changed over recent years due to some of the newer medicines that we have out there on the markets. Some of it has changed due to patients’ preferences. I think a lot of attention is now being paid towards ocular surface disease, and there is a lot of us who are trying to use more combination medicines that we can decrease the amount of preservative that we’re putting into these patients’ eyes.
Patients who have more advanced glaucoma are often taking six to 10 drops a day, and I think a lot of us are trying to decrease the number of total drops, and maybe even move towards some of the preservative-free agents for a lot of our patients. I think the medication landscape is changing, but I think the biggest thing is we have to keep in mind cost and compliance with all of our patients. So I think for a lot of us it’s trying to find the most effective medicine in the least number of bottles.
Dr. Bedrood: We know some patients progress despite getting treatment. Why do you think that happens?
Dr. Panarelli: I think a lot of it has to do with what is going on outside office visits, and that has to do with IOP fluctuation. And there are some good studies in the literature, as you mentioned earlier, to support this. I have been very surprised when I’ve sent some of my patients home with the iCare Home — this is a new device that allows us to check pressure around the clock. And some of the peaks in patients’ pressures are just not what I would have expected. So I think there’s a lot of fluctuation in pressures that we just are not catching when we check that pressure once every several months.
I think there’s also a factor of compliance here. And, again, that may be leading to some of the IOP fluctuation. And then as we talked about earlier, there are some pressure independent mechanisms at play here. We all know that glaucoma is a complex disease and pressure is really the only modifiable risk factor, but it surely is not the only risk factor at play here.
Dr. Bedrood: What are some of the unknown factors that contribute to progression?
Dr. Panarelli: I think there are several factors at play when we have to look at one of our patients who’s progressing despite seemingly good pressures. For some of my patients who are male and who are younger, one of the things I like to look at is whether or not this patient might have sleep apnea. I think that there’s definitely a large component of that for some of my patients with this normal tension glaucoma.
There are other risk factors that have to do with cerebral spinal fluid pressure, other factors with regards to blood flow to the optic nerve. But there’s a lot of variables here that we just can’t measure, and there’s not much we can do about it at this point. I still think in the end for a lot of our patients who are progressing, we need to check and make sure that they’re not spiking pressures. And, in the end, sometimes it means doing a filtering procedure to lower their pressure as much as possible.