Each quater I publish a newsletter to optometrists and GP’s. The March newsletter is available here for download from the downloads page

Surgical induced astigmatism (SIA)is a very real phenomenon and an area in which we are constantly improving. Most cataract surgeons today would perform cataract surgery through a 3.2mm clear corneal wound. These wounds are stable and providing that they are well constructed, generally do not leak. The only problem is that they induce a fair degree of astigmatism. This can be used to the surgeons benefit if placed on the steep corneal axis, as it can help to reduce any pre-existing astigmatism. Problems however arise if there is no pre-existing astigmatism as these patients can end up with post operative unwanted astigmatism. Worse still, the half a diopter of pre-existing astigmatism that they hope to eliminate with an on axis wound often, unpredictably results in a worsening of the astigmatism.

My ow view, which is shared by others, is the best approach is to reduce the amount of SIA by the use of small corneal wounds and controlling any astigmatism by either the use of toric lenses or by Limbal Relaxing Incisions (LRI’S).
For a number of years I have been performing 2.4mm wounds which in my hands still induce 0.25-0.5 diopters of SIA. Most recently I have moved to 2.2mm as new blades have become available. The rate limiting step at present is the size required to implant an Acrysoft lens. At present these are my preferred lenses as they have the lowest posterior capsular opacification (PCO) rates and the best toric platform to date. Baush and Lomb do make a lens that can be implanted through a 1.8 mm wound, but these lenses have much higher PCO rates.
It remains to be seen what effect, reducing my wound size has on SIA. Another benefit of going to a smaller wound is of course a lower risk of wound leak and a lower risk of endophthalmitis.