You really must learn this technique — it is an easy, effective, and predictable way of treating modest degrees of corneal astigmatism. In this video I give you my personal nomogram and method for success with paired phaco incisions. This is not a new idea, and in fact, it was first described decades ago and has stood the test of time.
There is some variation in the degree of astigmatic effect depending on multiple factors such as incision size, incision placement, incision position, incision tunnel length, patient age, corneal diameter and corneal pachymetry. For most of our cataract patients, the effect of these factors is limited, and we can come up with a reasonable and predictable nomogram to treat astigmatism.
A wider incision will induce more corneal flattening, as will more central placement, inside the limbal vessels. A shorter tunnel length will also cause more corneal flattening, but it may not seal as well as an incision with a longer tunnel length. Patient age can affect corneal rigidity, and we expect more effect in older patients. Small anterior segments with shorter white-to-white corneal diameters may have more effect from the same width incision as a larger eye.
We found that for patients with ATR astigmatism, placement of paired phaco incisions on the steep meridian gave an astigmatic benefit of 0.7 D of treatment, while those having WTR astigmatism, the effect was larger at about 1 D of flattening. We have since used this nomogram for many more patients and have found the results to be relatively consistent. I encourage you to try using paired phaco incisions in your own patients to address astigmatism at the time of cataract surgery.
My nomogram for astigmatism correction with paired 2.8 mm-wide incisions is:
Click below for the video about double phaco incisions to treat astigmatism: