8. Narrow Angles: The Eye Emergency You Didn't Know You Were At Risk For

Sudden severe eye pain. A headache that comes out of nowhere. Vision that goes blurry with halos around lights. Nausea. These are the signs of acute angle closure glaucoma — one of the true emergencies in eye medicine. And the scariest part? Many of the people it happens to had no idea they were at risk.

Narrow angles is one of those conditions that flies completely under the radar — until it doesn't. I find it in patients every single week during routine eye exams, quietly sitting there with zero symptoms, just waiting. And when I catch it early, we can prevent that emergency from ever happening.

I'm Dr. Parul Khator, a board-certified ophthalmologist and glaucoma specialist in Marietta, Georgia — and this episode might be one of the most important ones I record all season. Because narrow angles is a condition where knowledge truly can save your sight.

In this episode, I'll cover:

• What narrow angles actually means — and what's physically happening inside your eye
• How narrow angles and glaucoma are connected — and why one can trigger the other
• The warning signs of an acute angle closure attack that everyone should know
• Who is most at risk — including some surprising factors like your ethnicity and the shape of your eye
• The treatment options available — including a quick laser procedure that can prevent an emergency before it ever happens

You might have narrow angles right now and have absolutely no idea. This episode is your heads up. 👁️

📬 Have a question or topic you'd love me to cover? I'd love to hear from you! Email me at demystifytheeye1@gmail.com

📱 Follow along on social media: Find me everywhere @demystifytheeye

🌐 Learn more about Dr. Parul Khator, MD: https://www.gaeyepartners.com/metro-atlanta-eye-doctors/parul-khator-md/

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Demystify the Eye is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of your eye doctor or qualified healthcare provider with any questions you may have regarding your eye health.

Transcript

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Hello, my name is Parl Kator MD. I'm an ophthalmologist in Atlanta, Georgia, specializing in cataract and glaucoma surgeries. After practicing medicine for over a decade, I have learned that the more a patient knows about their disease, the better they do. Patient education is a passion of mine. But like most doctors, I have a lot of patients and not a lot of time to see them. So I created this podcast where I could spend the time I don't have during the day to give you insights into the eyeball and ocular disease. Let's empower you as a patient or a patient support system. Together, let's demystify the eye. Halloween is coming up soon for me, and it is my absolute favorite holiday. When I think of Halloween, I think of all the spooky things. Abandoned graveyards, zombies rising from the ground, axe-wielding murderers, the whole bit. While Halloween is a fun once-a-year exploration of scary things, there is something else that scares me year-round, and not in a fun way. The thing that really terrifies me? Acute angle closure glaucoma. Q and ear-piercing scream here. Acute angle closure is terrifying because it is one of the true medical emergencies in ophthalmology. We eye doctors are not, after all, ER doctors. We don't jump on a patient's gurney and stick our hands inside their chest to keep their heart beating after a gunshot wound. We work out of offices from eight to five and take care of patients who have booked their appointments months in advance. Our work lives are neat and tidy and organized. Until we encounter a patient with acute ankle closure glaucoma, then our clinics are turned upside down. This is because with acute angle closure, time is of the essence. Each second counts, and each minute might mean the difference between someone seeing or having devastating vision loss. Kind of makes those zombies seem like child's play. Pathophysiology. As I've said in previous episodes of this podcast, understanding a disease begins with an understanding of the anatomy of the tissue in question. So to understand acute angle closure, we first need to understand what the angle of the eye is. The clear front portion of the eye is called the cornea. This is the window of the eye that light enters first. Behind the cornea is a structure called the iris. This is the colored portion of the eye. There is a chamber of fluid between the cornea and the iris known as the anterior chamber. The fluid that fills this chamber is called aqueous humor. With a name like humor, you might think something funny is going on. But actually, humor goes back to an old medical theory called the humoral theory. Hippocrates posed that the body contained four humors or fluids and that an imbalance of any of these would lead to disease. It was a brilliant way of explaining disease in ancient Greece, but was of course eventually disproven. Even though Hippocrates' overall theory is incorrect, he sure was right about aqueous humor needing to be in balance. You see, aqueous humor does a lot of things for the eye. It helps the eye maintain its shape, gives the front of the eye oxygen and nutrients, and clears waste products. The amount of aqueous humor also determines the pressure of the eye. Think of a water balloon. The more water the balloon has, the higher the pressure. The less water, the lower the pressure. We know from a previous podcast that having too much pressure leads to glaucoma, so that's bad. But what's wrong with having too little pressure? Seems like an okay thing, right? Well, think about when the tire in your car has too little pressure. Makes it hard for your car to drive on the road. The tire really can't function that well. The same is true for the eye. When the pressure is too low, the eye collapses, creating pretty blurry vision. So it's a bit of a Goldilocks situation in that you want the pressure not to be too high or too low, but just right. If the pressure is determined by the amount of aqueous humor, then you don't want too much or too little of this fluid in the eye. So what determines how much aqueous humor is in an eye? First, let's review the structures in the front of our eyes. We already talked about the clear front portion of the eye or the cornea. The next structure back is the colored portion of the eye called the iris. This is the curtain shade of the eye. It determines how much light gets in our eye. The hole in the center of the colored portion is called the pupil. Behind the colored portion of the eye is the lens. The lens, if you will recall from the podcast on cataracts, is a structure we are all born with that sits in a bag, suspended in the center of our eye and just behind the colored portion of the eye. This lens helps us focus light. And as this lens grows and ages, it becomes a cataract. Just behind the colored portion of the eye and just in front of the lens is a structure called the ciliary body. This structure sits on the edge of our eye and goes around 360 degrees. Now, let's take a little stroll through the eye to see how fluid is made and how it is released. We begin with the ciliary body. If you remember, the ciliary body sits behind the iris and in front of the lens. The ciliary body makes aqueous humor for us. The fluid gets made here and then it travels forward to the front of the eye. It does this by cruising through the pupil. That's the hole in the center of the iris. To get from the ciliary body to the edge of the pupil, it has to snake between the iris and the lens. Once it is in the anterior chamber, that's the cavity in the front of the eye, it circulates, delivering oxygen and nutrients to all the structures in the front of the eye. After delivering its goodies, the aqueous humor needs to leave the eye so it can go back to the lungs to pick up new oxygen. Aqueous humor says adios to our eyes by exiting through the drain of the eye. This drain sits inside a structure called the angle of the eye. The angle of the eye is the place where the iris and the cornea meet. The angle is located in the periphery of our eyes and it runs 360 degrees around the entire circumference of the eye. It is tucked so far back into the periphery that even we eye doctors cannot see it with our giant microscopes unless we put a special lens on the front of the eye, which we will talk about in just a bit. The drain of our eyes actually consists of multiple layers. The aqueous humor slowly travels through these layers until it eventually reaches the brain, then the lungs, then the heart, where it can be recirculated. When someone has a problem with a drain of the eye, it is called open angle glaucoma. But what about when fluid cannot even reach the drain to begin with? If fluid cannot mechanically get to the drain of the eye, it is going to back up inside the eye. This backup of fluid then leads to a buildup of pressure. This buildup of pressure then damages the nerve in the back of the eye, leading to vision loss. Does this sound like a game of dominoes to you? It should, because everything in our bodies is connected. So a problem in one area will have a domino effect, creating larger and larger problems until eventually we end up with a disease. Classification. When fluid cannot reach the drain of the eye due to a mechanical problem with the angle, that situation is called narrow angles. We used to call this narrow angle glaucoma, but the spectrum of glaucomatous disease due to narrow angles recently got a makeover. I mean a full makeover with an entirely new classification system. Why did we reclassify this disease? Well, we realized we were not being specific enough. And if you know anything about doctors, you know we love to be as exact as possible. Before we jump into disease classification, we first need to cover what exactly we mean by narrow angles. Take a trip down memory lane with me to fifth grade math when we first learned about angles. We learned about right angles that were perfect 90-degree angles, obtuse angles that were wider than the perfect perpendicular 90, and acute angles that were smaller than that 90 degree angle. Now imagine you are looking at the eye in cross section. So if we had an eyeball in front of us, we would not look at it straight on. We would turn the eye to the side. Then we would slice that eye in half. Perhaps pause this podcast if you are eating lunch right now. We would remove the half closest to us and look at the remaining half. Now we are looking at one half of the eye from the inside. We can see the clear cornea that is at the front of the eye. This structure is a dome. Then we see the colored portion of the eye or iris coming out towards us. Where the cornea meets the iris, that's the angle we are interested in. Normal angles are 25 to 45 degrees wide. This means there is a lot of space between the cornea and the iris. Fluid has easy access to the drain that sits right where these two structures meet up. Angles that are mildly narrow, but not bad enough to give us major issues yet, are called narrow, non-occludable angles. This angle is anywhere from 10 to 25 degrees. When the angle becomes less than 10 degrees, we've got problems. Now the aqueous humor cannot reach the drain, and this is when it starts to back up. These less than 10 degree angles are called narrow occludable angles. So to review, 25 to 45 is normal. Less than 10 is what I call the danger zone, and in the middle from 10 to 25 is what I call limbo. So now that we know about angles, let's talk about you as a patient with narrow angles. Let's say your angles are occludable, so less than 10 degrees, but the situation is not yet so severe that fluid is backing up and creating a buildup in pressure. Your eye pressure is normal and you don't have any damage to that very important optic nerve in the back of your eye. At this point, you are a primary angle closure suspect. This does not mean you are shifty or shady in any way. It means we are suspicious that you could develop problems in the future. So we need to keep an eye on you. Yes, yes, pun intended. Now, let's say the situation is worse. Fluid is backing up and creating a buildup in pressure. Your eye pressure is high, but you don't yet have damage to the nerve in the back. At this point, you have primary angle closure. Now, let's say the situation gets even worse. Fluid is backing up, creating a buildup in pressure. Your eye pressure is high and you have damage to the nerve in the back of your eye, leading to vision loss. At this point, you have primary angle closure glaucoma. This process happens slowly, insidiously, so much so you may not even realize you have a problem until you have significant vision loss. One final terminology I'll tell you about is the dreaded, scary, frightening, terrifying, acute angle closure crisis. This is the worse than Halloween scary one. This is when the angle suddenly closes. So it goes from, let's say, five degrees down to zero degrees all of a sudden. All of a sudden, there is zero access to the drain of the eye. Our bodies are remarkably adaptable, but we need time to adapt. In this situation, there is no time, so your body cannot make healthy adaptive changes. Your pressure goes from 15 millimeters mercury to 90 millimeters mercury over the span of a few minutes. Boy oh boy, will you know this one is happening. The symptoms are intense, as we'll cover in a moment. This situation of a sudden and dramatic rise in pressure can lead to devastating vision loss in as little as 30 minutes. Trust me, I'm shuddering with you. Risk factors. I have seen patients with narrow angles that are all different ages and races, men and women. So everyone should be screened for narrow angles at every eye exam. However, there are some risk factors that could make you even more susceptible to developing this condition. Number one, the most important risk factor is the shape of your eye when you are born. We can be born tall, short, or average height. In much the same way, our eyes can be short, long, or average in length. And the cornea of our eyes, that's that little dome structure in the front of the eye, can be steep or flat. How do I know what shape my eye is? Well, there are tests we do in the office that can measure the shape of your eye precisely. But a simple thing you can look for at home is the prescription in your glasses for distance. If you have a minus in your glasses prescription for distance, you are nearsighted or myopic. You likely have a long eye or a steep cornea. If you have a plus in your glasses prescription, you are far sighted or hyperopic. You likely have a short eye or a flat cornea. Well, what if I don't wear glasses for distance? Then you are emetropic and likely have an average-shaped eye. Well, how do I know what's in my glasses prescription? Put your glasses on your face and then look at your eyes in the mirror. Do the glasses shrink the size of your eyes, making them seem smaller than they are? That's a minus or myopic prescription. Do the glasses enlarge the size of your eyes, making you look like a wide-eyed anime character? They likely have a plus or hyperopic prescription in them. Eyes that are shorter in length or that have a flatter cornea, aka hyperopic eyes, are at higher risk for narrow angles. You see, in these eyes, everything is already crowded. It's easy for a structure in the front of the eye to become even more crowded down the road. I happen to be very nearsighted. I have a really long eye. Even if I live to be 200, it's pretty unlikely anything in my eye will get crowded because my eye is so long. Number two, a family history of narrow angles. This makes sense because just like our height or body shape can be hereditary, so can the shape of our eyes. Now your mom and dad may not have any idea what you were talking about when you ask them if they ever had narrow angles, but they will likely remember getting treated for narrow angles because the treatment consists of a laser to the eye. We will cover this soon enough. Number three, East Asian ancestry. Many East Asians are born with short eyes. Narrow angles are quite common among this population. There are some studies that suggest over half of certain East Asian populations have narrow angles. The Inuit populace is also at increased risk for narrow angles. Number four, aging. I have treated patients in their 20s and 30s with narrow angles. I even have one patient I treated at the age of 12. She was East Asian in descent. However, most of my patients are over the age of 40. This is because at the age of 40, something in our eyes begins to grow. In all of us, every single one. That something is called the lens, and as this lens grows and becomes cloudy, it is called a cataract. If you will recall from the cataract podcast, every single human being begins developing cataracts at the age of 40. So what if I get a cataract? We're talking about narrow angles, right? Well, remember that patient who is born with a short crowded eye, they are okay until the lens in their eye begins to grow. As the lens grows, it creates further crowding, and this increased crowding or smooshing is what creates narrow angles. Number five, being a woman. Yes, ladies, unfortunately, being a woman is a risk factor for wide hips and narrow angles. Symptoms. Narrow angles can present in completely different ways depending on whether the ankle narrows slowly or all of a sudden. Let's talk about what a patient looks like when the angle narrows slowly. My patient MJ is a great example of this. He is a paralegal in Atlanta in his early 50s. He's in great shape with no health problems. He came to see me because he couldn't see out of his right eye and assumed he had developed a cataract. He did have cataracts in both eyes, but the cataracts were mild and symmetric. His vision, however, was not. He could only read three lines worse than the 2020 line in his right eye, and that too was a struggle. He could read the 2020 line easily in his left eye. This meant there was something else going on besides just cataracts in his right eye. When I took a peek in the back of his eyes, I saw an optic nerve that was pretty badly damaged in his right eye and a healthy nerve in his left eye. If you will recall, the optic nerve is a structure in the back of the eye that connects the eyeball with the brain. It is responsible for taking all the pictures we see and sending them to the brain for processing. If this structure gets damaged, it results in permanent vision loss. My patient's nerve damage in the right eye translated into a large blind spot just to the left of his central vision and including some of his central vision. This is why he couldn't see. The next step was to look at his eye pressure. Normal eye pressure is 10 to 21 millimeters mercury, and MJ was 13 millimeters mercury in his good eye and 26 millimeters mercury in his bad eye. The plot thickens. I took a look at his angles next. Now remember, normal angles go from 25 to 45 degrees. The angle in his good eye was seven degrees, and the angle in his bad eye was three degrees. He had narrow occlutable angles in both eyes, but that four-degree difference between the right and the left eyes created a significant difference in the eye pressure, which led to damage of his optic nerve and real functional vision loss. I asked MJ if he had noticed anything amiss: pain, headaches, light sensitivity, pressure. He said nothing came to mind. I asked him how he finally noticed the vision loss in his bad eye, and he said he got something in his good eye and rubbed it. When he did, he noticed he could not see the stop sign properly in front of him. Until that point, he had no idea he was losing vision. When angles narrow gradually, the pressure increase is slow, the nerve damage is slow, and the vision loss is slow. This means you can develop problems so slowly you don't even notice them happening. Hence the importance of getting an eye exam each year. Now, let's talk about what happens when the angles close all of a sudden. My patient, Olivia. Comes to mind. When I saw her seven years ago, she was 65 years old, and our initial meeting was dramatic, to say the least. I got a call from our answering service about a patient of the practice who said she was in tremendous pain and couldn't see. It was 2 45 in the morning. I had a feeling I knew what was going on, so I told her to meet me in the office ASAP. I rolled out of bed and into my car and was seeing her in my office 35 minutes later. She walked in with her daughter. She had her eyes closed and her daughter was guiding her by the arm. She was red in the face and sweating profusely. She sat in my office chair, grabbed the trash can, and immediately vomited into it. It was the seventh time she had vomited, her daughter told me. I asked Olivia when this had started, and she said she woke up in the middle of the night to use the bathroom. And everything hit her at once the moment she flicked on her bathroom light. She told me she had the worst headache of her life, and it felt like someone had taken her left eyeball out and put it into a microwave for too long. Not a bad description, really. It took a quite a bit of effort on her part to get her eyes open for me to take a look. But when she did, my suspicion was immediately confirmed. Her left eye was red as a meatball in marinara sauce. The cornea was so cloudy, it was light gray. Her pupil was not moving. Her eye pressure was 64 millimeters mercury. That is three times the higher end of normal. What do you think her angle was? That's right. It was zero degrees. Zero, folks. The angle in her other eye was five degrees with normal pressure. You see, my poor patient was in acute angle closure. This means her angle went from five degrees to zero degrees all of a sudden. This can happen at any time, but usually occurs when we go from dim lighting to bright lighting conditions, like turning on a bathroom light in the middle of the night, or leaving a movie theater and stepping out into the bright daylight. Her pressure went from normal to 64 millimeters mercury all of a sudden. And this created some startling symptoms because her eye did not have time to adapt. So now that you've heard about both ends of the spectrum, let's take a look at a final patient who is somewhere in the middle. Nancy is a patient of mine who saw me as a referral from her primary care doctor. She had been having bad headaches on and off for the last six months. Over-the-counter headache medicine wasn't cutting it, and neither was prescription strength migraine medicine. She also had blurry vision with the headaches, so the primary decided an eye exam was a good next step. When I spoke to Nancy, she said her headaches lasted about an hour or two. She had blurry vision and saw starbursts or halos around lights. Her friend once told her her eyes were red when she was having an episode. Nancy had five-degree angles in both eyes with normal pressure and no vision loss, but her optic nerves did look stressed. Nancy was experiencing something called intermittent angle closure. When she was having one of her episodes, her five-degree angle was decreasing to a one or two degree angle. Her pressure would go up and her eye would begin to go into crisis mode. However, after an hour or so, her angle would open back up and everything would revert back to normal. Over time, these crisis episodes were creating stress on her optic nerves. And soon that stress would turn into injury. Diagnosis. In medicine, there are screening tests and diagnostic tests. The screening test for narrow angles involves a doctor simply looking at your eye with her slit lamp machine. That's the giant microscope. She uses one beam of light to look at your eye. She then moves this beam out to the periphery of your eye and splits it into two beams. One beam lands on your cornea and the other on your iris. She then assesses the space between these two beams of light. Remember, the angle of the eye is the place where the cornea and the iris meet. If the space between the two beams of light is really narrow, she will tell you you might have narrow angles. The next step is the diagnostic test, which will confirm whether the screening test was correct. This diagnostic test is called gonioscopy. We put a little lens on the front of your eye and look with the slit lamp again. Yowsers. A lens on my eye? That doesn't sound fun. Not to worry. We numb your eye up first with a numbing drop. You don't feel the lens touching the surface of your eye, but your lids can try to squeeze against this lens, and that can feel weird. Patients will usually apologize to me the first time I do this test on them and they back away. There is no need to apologize, folks. If something comes at your eye, you should try to squeeze it out. You should back away. That is a natural, normal, and protective reflex. You just take a deep breath and start over again. With some good breathing and a little reassurance, my patients end up doing very well with this test. Once a patient is cooperative, this test only takes a few seconds to perform. The lens I put on your eye is called a gonio prism. And as the name implies, it consists of multiple prisms that allow for something really cool called internal reflection. So when light enters our prismatic lens, it gets bent, illuminating the angle of the eye. I can now see the colored portion of your eye as it comes across to meet your cornea. I can see if the insertion is steep or normal, and I can even grade how steep it is. This is the angle measurement we talked about earlier. Most importantly, I can use this lens to see your drainage structures. If your angles are open, the drainage structures are easily visible. The more narrow your angle gets, the less structures I'm able to see. And this helps me risk stratify you. During your narrow angle exam, I will also check your eye pressure to see if it is elevated. I will take a look in the back of your eye and peek at your optic nerve to see if there are any signs of stress or injury to this nerve. Now I can tell you if you are someone we need to watch or someone we need to treat. If your eye pressure is elevated, I will also start you on pressure-lowering drops in preparation for the treatment. Treatment. So now you've been diagnosed as having narrow angles that are narrow enough to warrant treatment. What does that treatment look like? Narrow angles are treated with a laser to the eye. Hold on. I'm sorry, what? That sounds scary. And sci-fi. And scary. I assure you it is not. The laser is called a peripheral laser iridotomy, and we will cover it in much more detail in a later podcast. If you notice, I am saying laser procedure and not laser surgery. This is because the laser is not performed in the operating room. It is performed in the clinic. Essentially, you sit in a machine just like the one you were in for your eye exam. Except this machine is hooked up to a laser. The procedure takes a few minutes and you heal from it in a day or so. What are we doing with the laser? We're putting a hole in the colored portion of your eye. Hold on. I'm sorry, what? Again, this sounds scarier than it is. The hole is microscopic, meaning you will not be able to see it when you look in a mirror. We will only be able to see it with the help of our large microscopes. The hole is created so that any aqueous humor or fluid that is trapped behind the colored portion of the eye can move forward. When fluid behind the iris moves in front of the iris, the iris falls backwards, away from the cornea. Remember, the angle of the eye is the space between the cornea and the iris. So if the iris falls backwards, the angle widens. Makes sense. If fluid is trapped behind the iris, it cannot get to your drain to leave your eye. Once that trapped fluid moves to the front of the eye, it can actually get to the drain. Less backed up fluid means lower pressure, which means a happier nerve. So how many holes do you have to make? I mean, you said the drain was 360 degrees around the periphery of my eye, so do you need to make holes 360 degrees around my eye as well? Thank goodness no. The eye is not divided up into compartments. The space behind the colored portion of the eye, which is called the sulcus, by the way, is all connected. So any fluid trapped back there, whether it is at 12 o'clock or 6 o'clock, can all flow out of the one hole I create. Because you do not need intravenous sedation for the laser, you do not have to have a driver for the appointment. Of course, if you want the moral support of having a family member or friend with you, go for it. The laser is only ever performed to one eye at a time with two weeks in between. So my patients say they feel comfortable driving home themselves. The really great thing about the treatment of narrow angles is that it is very rare for me to ever have to repeat the laser procedure on my patients. It is usually one and done. I perform 15 to 20 of these lasers a week and have been doing so for over a decade. I can count on one hand the number of times I've ever had to repeat one. However, it has happened. This means if you have had a laser treatment for narrow angles, you want to have your doctor check to make sure the hole that was created is still open. This needs to be done at least once a year and every single time you are dilated. Things to avoid. Until you have the laser treatment performed to both eyes, there are some things you need to avoid. These are the things that can make your angle narrow further. Remember, the name of the game is not to allow your angle to close. We cannot let you get to zero degrees. The things that will make an angle narrow further are things that dilate the pupil of the eye. For example, cold medicines, things like Pseudafed or Daequil, allergy medicines. This one is very painful for my patients since I live in Atlanta, which seems to us to be the allergy capital of the world. So things like Benadryl, sinus decongestants that have ephedrine in them, medicines for overactive bladder syndrome, detrol or ditropan are examples, nausea medicines like phenogin, asthma medicines like spariva or atropint, gastrointestinal medications like Xantac, and finally anxiety and depression medications like visceral, prozac, or Paxol. Now is not the time to be an anxious, asthmatic patient with heartburn in the middle of pollen season. The list I just gave you is not comprehensive. There are other medications not included on this list. So if you have narrow angles and you're not sure if your medicines are safe, call your ophthalmologist and ask them. I answer this question for my patients all the time. Conclusion. Narrow angles are actually really common, and yet no one seems to have heard about this important condition. I hope through this podcast you feel much more educated about this condition and you spread the word. Narrow angles are missed far too often. But if more people know about this condition, more people will know to ask their doctors to check them for this condition. Prevention is the key here. A simple two-minute laser procedure performed during the early stages of angle narrowing can keep you from having permanent damage and permanent vision loss later. So let's work together to make sure all the scary stuff is saved for Halloween. And on that note, I will leave you. Until next time, see well and be well. Thank you. You're welcome.