Hello and welcome to Case of the Day. I’m Dr Croley and we’re gonna discuss an interesting patient from today and then transpose that over to talking about glaucoma.
So we had a lady come in today, unfortunately had not been seen for many years, never had an eye exam. Comes in, she has no real complaints per se, but we measured her eye pressure. Her eye pressure was 26 on both eyes. The normal pressure is 10 to 21 so this increased pressure could be a contributing factor as far as her developing glaucoma. It’s not the only factor, it turns out that glaucoma is a multifactorial disease, probably eye pressure being the most prevalent of the different factors involved and so when I tell someone they may have glaucoma, their first question is, ‘What is glaucoma?’
So we’re gonna go over that so we can explain to you what glaucoma really is. So first thing you need to know is a little bit of the anatomy. We’ll go over what the anatomy of the eye is. So, in the back behind where your blue part or brown part of iris behind that is a ciliary body. This part of your eye that you can’t see, produces the fluid that fills up your eye, it then percolates, comes forward through the pupil, and then fills up the front of your eye. This anterior chamber is filled with fluid or the aqueous humor. Then, the fluid then drains into what this is called the trabecular meshwork. This meshwork goes all the way around your eye 360 degrees sort of right where the white part starts. And so this white part is called the sclera and so right in this area, there’s a meshwork and this looks like cheesecloth. There’s little fibers going back and forth, just like cheesecloth, and the fluid filters through in this cheesecloth into Schlemm’s canal and then eventually into a vein and out of your eye. So there’s a constant production of fluid in your eye and it caused an outflow of fluid in your eye.
There are two basic types of glaucoma and they’re based on anatomy. So, in open angle glaucoma, which is what we’re gonna talk about mostly today, is that angle between this cornea – the clear part of your eye, and the blue or brown part – that angle is open; just like in this case. So the fluid has every opportunity to get to the trabecular meshwork and then filter through the eye.
Angle closure glaucoma, which only comprises a few percentage of glaucoma cases. Open angle is better than 90 percent of all glaucoma cases. So, in acute angle closure, angle closure glaucoma, this iris comes up this way and across so the iris butts up against the meshwork; that’s like putting a stopper on the sink. No fluid can get out of your eye and your pressure goes out the roof, and you’re now, now, this is one type of glaucoma that does have symptoms. These people come in, their pupil’s dilated, their eyes red, your visions very poor and they’re in severe pain, nausea, throwing up, vomiting, really severe problem. But that’s a very uncommon circumstance.
For almost all other cases we’re gonna talk about open angle glaucoma. Now why does this have trouble getting out, the fluid getting out of this meshwork? Some of that has to do with genetics and so this meshwork gradually fills up with the material that blocks the flow out of your eye. It could be either pigment from your iris – it’s called pigmentary glaucoma, which is a type of glaucoma, or it could be the meshwork fills up with a different kind of material and so therefore there’s a slow backup. People with typical open angle glaucoma, the pressure may be in their twenties, or thirties, sometimes to forties but it’s not as elevated and this is a chronic condition. And what happens is, increased pressure inside your eye then damages the nerve in the back of the eye which is responsible for taking the vision from your retina back to your brain. So this nerve over time gets damaged.
Glaucoma doesn’t cause symptoms because it slowly causes damage to the nerve and you lose tiny little pieces of your side vision slowly over months or even maybe years of time and so you don’t notice any symptoms. And it’s so slow that almost never does anybody come into my office and say, ‘Hey doc I think I got loss of my side vision, I think I got glaucoma.’ Doesn’t happen. It’s so slow you learn on your own subconsciously – you turn your head more because that vision’s missing or your brain kinda learns this, you gotta move your eye over here more and you learn to compensate for that.
So, once we determine that you have glaucoma, in almost all cases, the pressure is elevated that damage the nerve. There’s a lesser form of glaucoma called normal pressure or low pressure glaucoma that’s a little more complicated that we can discuss at a later date. So, once we determine your pressure’s too high it’s gonna damage your nerve or has damaged your nerve, then we have to decide on treatment.
There’s two or three different choices of treatment. One, there are different medications that either slow down the production of fluid in your eye or two, help the outflow of fluid through out of your eye. We also have laser treatment where we laser this area where the meshwork is and the laser treatment opens up those channels and lets the fluid drain out further. And if all those two things fail, then the last resort is surgery. So we actually make an opening through into the eye to let the fluid drain out of the eye. So there’s three ways of treating Glaucoma. Typically speaking, it would either be medications, eye drops, or laser treatment.
Different doctors decide to do different things as far as what they would recommend. First, in my hands, I give people the choice, if they come in with a new case of glaucoma, I tell them there’s medications we can put in their eye that will then bring the pressure down. We usually set a target pressure depending on how bad the glaucoma is and where the pressure was the first time we checked it. We set a target pressure where we think what is gonna be a safe level and then go from there. So for instance if your pressure is 29 and your optic nerve is healthy, my target pressure may only be 19. If you have had severe damage to your optic nerve and we’re worried you’re gonna lose your vision totally, then my target pressure may be 10 or 11. So it varies depending on the severity of your disease.
So I usually let people have a choice. We can do the laser treatment, that works very well, or we can put someone on eyedrops and that works well, as well. So that’s the general gist of what glaucoma’s about and why we get glaucoma, and what happens in the eye from glaucoma.
If you have any questions about what we’ve gone over, you can contact me through the website or write us an email or contact us through the website. So that’s for today. Next time we’re gonna come up with something new that will hopefully inform you and will be interested in knowing about. Until then may God bless you with healthy eyes and great vision.