What Does Minimally Invasive Mean?

So canaloplasty is often described as a “minimally invasive surgery”. What does that mean, “minimally invasive”? Well, in order to understand that we really need to compare it to the traditional surgeries of trabeculectomy and tubes or shunts.Traditional surgeries require creating a full thickness hole or fistula in the wall of the eye. That hole is then left open, although it is guarded – either by flap or by a valve or sometimes temporarily by a suture. That guard however is not a complete guard, and so fluid does essentially have a straight flow out of the eye. It flows underneath the surface of the top layer of the eye, called the conjunctiva. This conjunctiva forms what is called the bleb in the case of a trabeculectomy or covers the actual plate of a shunt allowing a reservoir of fluid to collect. That fluid then drains out. Exactly how? We’re not exactly sure, but somehow it does get out of that reservoir and back into the venous system.

Canaloplasty as well as viscocanalostomy and other non-penetrating surgeries, do not require a creation of a full thickness, fistula. As a matter of fact the incision, once the drainage system has been opened, the drainage system being Schlemm’s canal, which is the natural aqua duct that fluid leaves the eye through. Once that has been opened with a gel (in a case of both viscocanalostomy and canaloplasty) as well as with a suture stenting it open (in the case of canaloplasty) then the flap that was created to gain access to the canal is closed back down with the suture. So there really is no full thickness flow from the inside of the eye to the outside of the eye. And any flow that does go from inside to the outside of the eye is temporary during healing process. And once the eye has been healed, the flow really should be through the natural drainage duct, Schlemm’s canal into what are called collector channels and then into the venous system. So that’s what is meant by minimally invasive or non-penetrating.