Although canaloplasty is a safer surgery when compared with more traditional glaucoma surgeries such as trabeculectomy and tubes, it is surgery, and so there are risks needed to be associated with it. It is important to note that with glaucoma, left untreated, vision will eventually be lost and blindness would result. So, glaucoma must be treated either with drops or surgery. Canaloplasty, as mentioned thus have a fewer risks, so let’s go through some of those risks.
RISK OF CANALOPLASTY
Although not exhaustive, some of the risks of canaloplasty include, bleeding in the eye, pressure elevation or spike, the formation of a bleb, descemet’s membrane detachment, the need to perform traditional glaucoma surgery, hypotony or pressure that is too low and infection.
BLEEDING IN THE EYE
Bleeding in the eye. Bleeding in the eye can occur up to a third of the time after canaloplasty. Although I mentioned this is a risk, it’s actually something that we expect and even want to see. Generally, when the canal is opened, and the fluid is able to communicate with some of the venous blood system, some of the blood refluxes back into the eye. This is a good thing, since it tells me, the surgeon, that indeed the canal has opened up. Generally, this blood in the eye will go away within a week, usually two weeks at the most, and the vision returns to what it was.
IOP SPIKE OR ELEVATION
Intra Ocular Pressure spike or elevation. It is possible most often shortly after surgery or few weeks after, to have a pressure elevation possibly than higher than it was before surgery. Generally, this is not concerning to me, the surgeon, and can even be expected. By two to three months out, most everyone who’s gone through canaloplasty has pressures that are lower than they were before surgery.
FORMATION OF A BLEB
Formation of a bleb. About 6% of the time, a bleb can form after canaloplasty. Generally, if a bleb forms after canaloplasty, it is not associated with irritation, redness and the chronic conditions that can be seen with a bleb associated with trabeculectomy.
DESCEMET’S MEMBRANE DETACHMENT
Descemet’s membrane detachment or separation. During the visco dilation process of canaloplasty where a special gel is actually used to open the canal, just like a balloon is used to open the artery in angioplasty. Sometimes this gel can dissect underneath the cornea, resulting to a blister, what’s called a descemet’s membrane detachment. Generally, this is not something that affects vision and it often resolved on its own. In a few cases where it does not resolved on its own, it can generally be pushed out of the way or flatten with an injection of gas bubble in the eye.
NEED TO PERFORM TRADITIONAL GLAUCOMA SURGERY
The need to perform traditional glaucoma surgery. Because most people who choose canaloplasty are doing so in order to avoid traditional glaucoma surgery, this can actually be considered a risk. The good news is that less than one in twenty people who had canaloplasty need to go on traditional surgery. Now, this maybe decided at the time of surgery or it maybe years down the line. The vast majority of people that had canaloplasty do not need additional glaucoma surgery.
HYPOTONY (LOW IOP)
Hypotony or a pressure that’s too low. You may be wondering if the whole point of surgery is to lower the pressure, how it can be too low? Well, it turns out that, generally, below 5mm Hg (mercury), the pressure can actually be too low for the eye and vision can be lost. Now, the good news with canaloplasty is that this is very rare. About one in two hundred people end up with pressures that stay too low.
Infection. One risk that’s common to all surgeries is the risk of infection. With eye surgery that risk is particularly concerning because an infection in the eye can lead to loss of vision, even blindness. With traditional glaucoma surgeries such as trabeculectomy, the risk of infection can be quite high, as high as 5% per year after surgery. That risk does not seem to disappear, regardless of how far out from the surgery one is. One of the great things about canaloplasty is that because there’s generally no bleb that ongoing risk should not exist with canaloplasty. As a matter of fact, as of early 2012, no one has been reported to have lost a significant amount of vision from infection, from canaloplasty.