The disease can be managed, but is only detected through an eye examination. Dr. Katherine Loftfield, an ophthalmologist with Ochsner Health System, discusses glaucoma, risk factors for the disease and why early detection is critical.
Q: Glaucoma isn't just one disease, but the term refers to a group of diseases. What's the common feature for the various forms of the disease?
A: What they have in common is damage to the optic nerve and that damage results in visual loss and (a lessening of) visual function. All of the glaucomas are related to the pressure within the eye. It can be a normal pressure or elevated pressure; usually it's an elevated pressure. To create a pressure within the eye, you have to have, so to speak, the faucets on and the drain open. (Normally) fluid is constantly made in the eye; it maintains the pressure and it's constantly draining.
Q: What is IOP?
A: IOP stands for intraocular pressure. It's a result of what fluid is coming into the eye and how quickly the fluid is draining out of the eye. It's analogous to a basketball. You have to have pressure within the basketball, or else it loses its shape and squishes up like a raisin. So you need to have some pressure within the eye or else it won't maintain its shape and it won't function.
Q: Glaucoma has been referred to as the "silent thief" because it can rob a person of their vision before they know what's happened. How does this occur?
A: Optic nerve damage happens slowly over time and it usually [begins] with loss of your side vision before it infringes on your central vision. People aren't aware if their side vision is slowly, slowly disappearing. It's not until the central vision gets involved that people become symptomatic at all. This (the most common form of glaucoma) is called either primary open angle glaucoma or sometimes it's referred to as chronic open angle glaucoma. There's an increased resistance, so it's kind of like your drain has some crud in it and it's not draining as well.
Q: There's another type of glaucoma that can develop quite suddenly how suddenly?
A: In angle closure glaucoma, the fluid suddenly doesn't have access to the drainage system. The iris root comes up and it occludes the angle, so all of a sudden the drain is completely closed, so the pressure goes really high and that's a dramatic event as opposed to slowly, slowly increasing the pressure. The symptoms are very impressivethey get blurred vision, a red eye, severe headaches, and even nausea and vomiting. Patients who get an acute angle closure event are usually very aware that something has happened, so they'll usually go to an eye doctor or an emergency room within a few hours.
Q: Is glaucoma preventable?
A: It's not preventable because [there] seems to be a genetic pre-disposition (for some people to be more at risk of developing it than others). There's no way we can keep you from getting glaucoma if you're going to develop it. If you diagnose it early and begin treatment, you can maintain sight. Usually, you can prevent the vision loss from it as long as you catch it early.
Q: What are some of the other risk factors?
A: The main risk factor is the intraocular pressure. Unfortunately, not everyone who has glaucoma has elevated eye pressure; there is a subgroup that has normal eye pressure and still can get the glaucoma optic nerve damage. Those people are what we call normal pressure glaucomas and they're a little bit more difficult to treat because you start with a normal pressure and all you can do is to try to get it even lower. Age of the patient increases the incidence of glaucoma, race is a factor (it's) more prevalent in African Americans and presents at a younger age and a little bit more aggressively and a family history of the disease. There are some minor risk factors diabetes, hypertension, myopia or nearsightedness which they're not sure but they think might contribute to the risk.
Q: Can an ophthalmologist easily detect glaucoma?
A: It's actually not always that easy because there's no one good screening tool for it, so you have to use a combination of things to make the diagnosis. Sometimes it's very obvious, but sometimes it's more subtle. For a screening, we'll usually check the intraocular pressure and give a good examination of the optic nerve. These are a part of a normal eye exam.
Q: How is it treated?
A: The initial treatment is done with eye drops all treatments are aimed at lowering the eye pressure, which is actually the only thing we know how to manipulate of the risk factors. Eye drops are used and we can do some laser treatments. There are a few pills we can use, but we don't usually use them because they have a lot of side effects.
Q: How often should people get their eyes checked?
A: It's age dependent, but by the time you're 60 years old, they say you should go every year. I'd probably say every two years if nothing else is going on.