Limbal relaxing incisions (LRIs) are useful for treating mild to moderate degrees of corneal astigmatism at the time of cataract surgery. These circumferential incisions are made at about 80 to 90% depth in the peripheral cornea. Despite the name, LRIs are actually not made right at the limbus, rather they are inside the limbus in the peripheral cornea.
There is a small risk, much less than 1% in my hands, of corneal perforation when doing an LRI. Because the LRI is perpendicular to the corneal surface, a full thickness perforation will create an incision that is difficult to close. It will certainly require sutures for proper closure.
If the LRI is done at the beginning of the cataract surgery and there is a corneal perforation, it will leak throughout the entire case and cause an imbalance in fluidics. This makes the cataract surgery higher risk for further complications like a ruptured posterior capsule.
We are there primarily for the cataract surgery and secondarily for the treatment of the astigmatism. Do the cataract surgery first and when that is completed, with a nicely centered IOL in the capsular bag, then address the corneal astigmatism with the LRI. If there is a perforation at this point, it is far easier to manage.
Click below to see more about LRIs at the time of cataract surgery: