Intraocular Pressure: Getting to the Bottom of It
Why do some experience intraocular pressure while others do not? Why the injustice?
Everyone has and needs intraocular pressure. But while everyone is concerned with having higher-than-normal pressure, lower-than-normal levels are just as bad – the eye can’t keep its shape and there isn’t enough fluid to nourish the internal organs. Higher pressures lead to glaucoma, which puts stress on the optic nerve and causes it to atrophy. Normal pressure is measured from a 10 to 20, but just like everything else (blood pressure, for example) you can’t take statistics from the general population and apply that to a specific person. There are people who measure at 20 and do not have glaucoma, and 50% of people who already have glaucoma are lower than 21. Pressure, however, is the only factor we can control.
Do elevated pressures vary between nations and nationalities?
Yes. African-Americans, for example, are 10 times more likely to develop glaucoma, even with normal eye pressure.
How does it manifest itself subjectively? Does the person always feel something? Like the eye is being pulled apart, or that it might explode?
There aren’t any obvious symptoms until the pressure gets very high, like 40 or 50, where the patient feels acute discomfort, headaches, or something else that they can’t identify the cause of. And at middle-pressures, the eye doesn’t turn red or hurt, and vision isn’t affected, either.
So you might ignore glaucoma at first?
That’s why it’s often called the “silent thief”.
What are the statistics regarding age?
If you’re over the age of 65, there’s a 20% chance you have glaucoma. Older than 70 – 30%. Older than 85 – 40%. With age, the outflow of liquid from the eye decreases. If there are cataracts, as well, clouded lenses exacerbate those problems. In short, glaucoma gets worse and more common with age.
Well, that’s not just the case with eyes. It’s our fate. So if I’m 40 and have no complaints, how often should I see you?
If your family has a history of glaucoma, at least once a year.
I wonder, by the way, if people really come to you for check-ups, or only when things are already bad.
Presbyopia usually starts around age 40, and this brings people to the ophthalmologist for glasses or other measures. But there are some who come for the first time at age 55, and already have advanced glaucoma.
Is it Russian-speaking people?
It’s inherent in all people, but more common in our own. Immigrants from Eastern Europe commonly get pseudoexfoliation glaucoma.
Pseudo…exfoliation? Sounds scary!
This is a special type of glaucoma that has very strange behavior. Flakes form in the eye which are deposited in the trabecular meshwork and cause cataracts and glaucoma. It is difficult to treat. Russian Jews, Poles, Lithuanians, and other Eastern Europeans need routine check-ups, because they are at a higher risk.
What is regular exfoliation glaucoma?
It’s caused by environmental exposure. For example, this is often the case with glass-blowers, who are exposed to infrared radiation that causes peeling of the lens capsule. With the Jews we mentioned before, it looks the same, as if they were blowing glass, as well.
I understand that not all Jews are glass-blowers, so why is that type of glaucoma called pseudoexfoliation? Is there a hypothesis to explain this phenomenon?
There are hypotheses, yes, but that’s another conversation. The disease acts simultaneously like an infection and hereditary condition, as well as an environmental one. People from certain geographical areas suffer from glaucoma more often, though, suggesting something about the water, air, or local food.
Understood, but how is it like an infectious disease? You can’t “catch” it.
Let’s say a husband has pseudoexfoliation in his right eye and his wife develops the same. They aren’t blood relatives, but the disease manifests itself in both people. They’ve just lived in close contact for a long time.
Is it a “pseudoexfoliation pseudoinfection”?
Maybe not pseudo, because it’s still possible that it’s caused by a virus; we just don’t know. Take, for example, stomach cancer. It is the #1 killer in Japan, so the government requires mandatory testing. But Japanese that have come to the United States are at a much lower risk. Even Japanese that have lived here for a long time and move back to Japan are at a lower risk. It isn’t the food, because they eat mostly the same here.
(to be continued)