From watching our videos, you know that for most cases, I find that a 5 mm capsulorhexis is ideal. This allows a 0.5 mm overlap of the optic for a full 360 degrees for IOLs with a 6 mm diameter. Even a 5.5 mm capsulorhexis is great as long as it is well-centered. We sometimes make a small capsulorhexis if we are doing a combined case such as cataract + corneal surgery, cataract + glaucoma surgery, or cataract + retina surgery. With a smaller capsulorhexis we can be more certain that the IOL will stay within the capsular bag even if the anterior chamber shallows in glaucoma surgery or if there is posterior pressure from a gas bubble in the vitreous cavity from retina surgery.
Click below to hear what is the smallest permissible capsulorhexis size: