Hello! Welcome to Case of the Day. I’m Dr. Croley and today we’re gonna discuss a sort of newer type of glaucoma procedure called canalaplasty. Had three patients come in today for their first post-operative day, that we did three of those procedures yesterday, and their pressures are doing very well, so we thought we’d discuss a little bit about this new procedure for glaucoma, or a newer procedure.
First, what is glaucoma. Glaucoma, in simple terms, in most cases means the eye pressure inside the eye is higher than normal, there are exceptions to that, and that higher pressure damages the nerve in the back of the eye which leads slowly overtime to loss of your vision. It doesn’t typically blur the vision until the late stages, and so it slowly steals pieces of your side vision where people don’t really notice this. So most people don’t know they have glaucoma unless they go to an eye doctor and find out that their pressure’s elevated, usually.
So what do we do about and how does glaucoma happen? What goes on? So there’s a process ciliary body that sits behind your iris or the blue or brown part of your eye. This part of the eye produces fluid. The fluid then goes in front of your lens, between the lens in your iris, goes to your pupil and fills up the space between the clear part in your iris, this anterior chamber and the fluid fills up the anterior chamber, and then flows over to the peripheral part and there’s a little meshwork, called Trabecular meshwork, the fluid flows there into what’s called Schlemm’s canal and this canal meshwork circles all the way around the eye. From Schlemm’s canal there are outlet channels that then spread out and then the fluid then drains into a vein into the veinous side of your blood system. There’s a constant flow in and a constant flow out and that’s usually maintained in the normal pressure of between 10 and 21.
In glaucoma, in most cases, this meshwork is obstructing the flow through the system. The fluid can’t get out so the pressure builds up.
Medications can be used to treat glaucoma. There’s laser treatment to this that can be used. We were doing, in most cases, the two or three cases we did yesterday, they were having cataract surgery so at the same time, while we were removing that cataract we did this canalaplasty because they were on maximum medical therapy and borderline control and so this gave them an opportunity to get better control maybe even without medications.
So what do we do with canalaplasty? How does that work? Typically speaking, with a typical glaucoma procedure, we’re making a flap on the white part of the eye dissected it in through the cornea, making a hole all the way in the eye and letting fluid filter out through this white part of the eye and there’s another coating called the conjunctiva, and then it flows in through there out to the underneath coating and it forms a little bubble on the top part underneath the lid, and so that’s how we lower the pressure by having it leak out through the eye into the outer coating underneath the conjunctiva.
One of the disadvantages of that system, that procedure has been around a long time is in regular trabeculectomies, maybe 10 percent of people’s filter, that blab that little cyst forms an infection and they end up with severe infection in their eye. So canalaplasty gets around that because there’s no filtering blab.
What’s the difference about canalaplasty is that we make a flap or incision 400 microns deep through the outer white part up to the cornea, the clear part of the eye, and then inside that flap we make a smaller flap, and then we dissect this down, just above the underlying coating of the choroid so we’re just barely still in the white part and we go up and actually dissect in until we actually enter this canal.
So the dissection has been very precise, we enter to this canal, we open up a little section of the canal, and then what’s done is we have a very small 200-micron catheter that has a flashing beacon on the red light on the end. We pass this through the canal and run it all the way around the eye and we can watch it because the light is flashing because it goes around and then it comes back out to the other side.
So what’s done is we tie a 9-o-prowling suture to the end of the catheter and then we pull it back and pull the suture back around, all the way around and bring the suture out. So now we have two ends of the suture outside of the eye. And we then cut one little piece of the flap off, that’s to keep the outside flap still present. Then we tighten that suture down to stretch this canal open a little bit, and then tie it off. And then we then suture the flap back down so there’s no leaking of the fluid outside of the eye. What this does is open up this channel and these filler channels so the fluid can go through this normal pathway by just a more efficient manner.
So that’s some advantages of less complications versus the older type techniques. It lowers the pressure pretty significantly; we get a 30 something percent reduction in eye pressure from what it was before with this procedure and if we combine that with cataract surgery, something like 43 percent reduction after cataract surgery and a combined canalaplasty reduction of the intraocular pressure. So it’s a very successful procedure
I think, gradually overtime more and more doctors would be trying this because it does have an advantage of less complications compared to a shot or to a regular trabeculectomy. In certain cases, this is a good procedure to perform to control the pressure and glaucoma.
If you have any other questions you’d like to know about canalaplasty or other things about glaucoma, feel free to contact us through the website. We’ll be happy to try to answer your questions. If not, may God bless you with healthy eyes and great vision.