Xiongfei Liu, MD
Glaucoma and Cataract Specialist
Glaucoma can affect people of all age groups, but the most common glaucoma presentation (what we referred to as primary open angle glaucoma) tends to occur in people of older age. And it is also this group that is vulnerable to COVID-19, and leaving home to come to the clinic can be challenging as well as daunting. Despite a protective and strict protocol set forth and followed by all medical staff at the clinic, some people nevertheless don’t want to gamble to come to the clinic. Therefore, the purpose of my blog is to discuss with everyone the general topics on glaucoma, ranging from the cause of monitoring and to treatment. With a better understanding of the disease, one can make a better decision about when to follow up in the clinic. Today, I just want to start out this blog with some general questions and answers.
Glaucoma refers to degenerative damage that affects the optic nerve, which is the neuro pathway that connects the eyeball to the brain. Millions of neuron courses through the optic nerve, and it is damage to these neurons that eventually manifest in glaucoma symptoms such as decreased peripheral vision and eventually blindness. Injury to neurons that make up the optic nerve come in the form of mechanical and vasculature components. For the former, increased eye pressure that is greater than what the neuron can tolerate can lead to the death of the neurons. For the latter, inadequate blood perfusion is the culprit. We as the medical field in general are pretty good at treating the former through medical and surgical therapy that lowers eye pressure. For the latter, we are scratching our head for a tried and true treatment.
A lot of routine eye exams include direct visualization of the optic nerve as well as digital imaging of the thickness of the neuron at a specific distance from the optic nerve. At times, these findings look in line with glaucoma presentation, and therefore the patients get referred to a glaucoma specialist. In glaucoma, as the disease progressed, the rim of the optic nerve becomes thinner and thinner till it cupped out; in addition, the thickness of the neuron layer tends to decrease at a significantly faster rate than normal aging. The key here is that there is a progression through time. For some individuals, their optic nerve contour looks somewhat concerning for glaucoma, but they have a clean visual field with no other major risk factors, so the concern for glaucoma is there but relatively small, so to really pin it on glaucoma, there should be a progression through time. Therefore, regular follow up with glaucoma doctor is important to discern whether there is true glaucoma or just a physiologic finding that mimics glaucoma.
As I mentioned earlier, neurons get damaged by eye pressure that is too high. But what is too high? It is different for each individual. Most eyes would progress toward glaucoma through time if pressure for example is very high such as in the 30s and 40s. But those in the low 20s can respond differently depending on the individual. What’s more, even if your pressure is in the 10s, some (definitely minority) can still progress. It ultimately depends on how your neurons respond to the local pressure exerted on them. When the eye pressure is in the 20s without major risk factors, I will usually discuss with my patients about the options of observation versus treatment, which likely consists of eye drop or laser. For observation, it really requires a couple of rounds of imaging and visual fields to confirm stability. People have different preferences: some don’t like to have a ticking bomb that disrupts their peace, therefore they want to start eye drop (which can be a lifetime commitment) right away. For others, the concept of less is more holds true. Nevertheless, if stability can’t be maintained from imaging or if the patients have difficulty following up, then eye drop can be the safer option.
Glaucoma tends to occur in both eyes, though often not in a symmetrical way. This can be due to many factors such as prior trauma, sleeping positions, or at times we just don’t know why. Glaucoma is different from cancer in many ways, and one is that it doesn’t spread. The story that one hears regarding one eye acquired glaucoma from the fellow glaucoma eye really steams from the fact that glaucoma took hold in both eyes in an asymmetrical fashion with different progression rates, and as glaucoma become worse in the less affected eye, one misunderstood actual progression in the better eye as spread from the worse eye.
That is a loaded question right there, but most likely the answer will be no. Obviously, it depends on at which stage we caught glaucoma that you have. If the stage is advanced with central tunnel vision left, then the chance of going blind is of course high. But even under these circumstances, as long as we can control the eye pressure to an artificially low level, the progression can be halt (but the peripheral vision will not improve). Needless to say, if you have mild glaucoma, the chance of going blind is much lower once the pressure is optimized. However, there is a subset of patients that despite seemingly good eye pressure control, the eye still deteriorates in a glaucomatous fashion. The driving force here likely stems from the vasculature. There are a few risk factors that are associated with this clinical finding, and optimizing these factors could slow the progression. We are also trying to incorporate newer technology such as OCTA to imaging the vascular component to further elucidate the cause and effect through this pathway in disease progression.
Glaucoma comes in many forms, but for primary open angle glaucoma (the most common type), having the first relative with glaucoma definitely put one at higher risk for having glaucoma. The higher the number of relatives, the higher the risk. But don’t panic, the key to approach glaucoma is to be consistent and persistent. Consistent in that you need to make an appointment with your glaucoma doctor for initial evaluation as well as regular follow-up, Persistent in that if you do need eye drop for pressure control, have disciple and stick to it. These two principles will carry you far and help you preserve your eyesight from glaucoma for as long as you can, and likely longer than you think.
The visual field test to me is very interesting. When I was in high school taking tests, my gut feeling right after an exam was pretty consistent with my eventual score. But in college, I could struggle through the whole exam thinking I failed and regret about going out too much, only in the end with a better than expected score. The visual field test is similar to these head-scratching college exams. You think you are doing bad because you struggle to see the target, but in reality, the result is not as bad as you think because it is graded on a curve, and that target sometimes really going over the threshold into a spectrum that is hard for people to see.
The 3 major treatment options breakdown into laser, medical, and surgical therapy. I will go over in detail regarding each of them in later blog. For now, we are really happy with the direction that we are heading toward the realm of glaucoma treatment. In the last decade, we have expanded our treatment arsenal to include new eye drop like Rhopressa or Vyzulta, as well as Minimally Invasive Glaucoma Surgery (MIGS) that really bridge the gap between medical therapy and big glaucoma surgery in the name of trabeculectomy and glaucoma drainage implant. Technology has really made a big jump in our treatment efficacy, and we are trying to bring the very best and advanced technology tailored to your need.
Nope, absolutely not! Keep your head high. Instead, focus on what we can do! Your doctor will be with you every step along the way to preserve your vision for as long as we can. And yes we can!
Good question, especially during COVID-19. In terms of pressure monitoring, there is iCare that is available for patients to take eye pressure at home. It does require a certain amount of dexterity, and that second person is really helpful. In my opinion, even if someone has all the money in the world, home iCare is still not needed for everyone. It is mostly useful for patients with progressing visual field damage despite a seemingly decent eye pressure in the office. Another area would be the home iPad visual field. The technology is constantly improving, and these visual field software are getting better and better. But the standard visual field in the clinic is still the gold standard for all other test comparisons, therefore coming to the office to get visual field is a good way to keep track of your glaucoma status.