Dr Oyakawa,
I am not sure I understand the opposite corneal incision correctly. My interpretation is that the it can be used to offset pre-exist astigmatism during the cataract surgery. More important, I want to confirm this will not introduce any more incision to the cornea like LRI.
I have another posting earlier 'What is opposite clear corneal incision'. One of the member responds this is the surgical induced astigmatism and introduced your presentation in youtube. Can you confirm that ? Is surgical induced astigmatism always bad ? Can it be used positively to offset some pre-exist astigmatism.
Thanks
All cataract incisions induces astigmatism. The smaller incisions induce less astigmatic changes. Surgically induced astigmatism can be used your advantage by using it to decrease pre-existing astigmatism. However, the amount is small around 0.5 diopters as mentioned above. Many surgeon do not use a vector analysis to look at astigmatism. If the surgeon makes a cataract incision temporally ( 0 or 180 degrees), the incision will reduced astigmatism by approximately 0.5 diopters on this axis. This will reduce astigmatism by about 0.5 diopters in an eye with against-the-rule astigmatism, BUT increase astigmatism by about 0.5 diopters in an eye with with-the-rule astigmatism. This is a very simple exam. Vector analysis has to be used when the steep axis of astigmatism is not 90 degrees from the surgical axis.
Dr. O.