Your Ophthalmology Against The Rule hosts Dr Ben LaHood and Dr Nick Andrew discuss the latest evidence and their views on refining the outcome of second eye cataract surgery. Modern IOL calculation formulae are very good at predicting a refractive outcome but not yet perfect. Can we improve any further by considering how the first eye responded to surgery? This may seem like a simple question on the surface but there are other issues to consider such as biometry error and IOL manufacturing tolerances. This lively discussion is sure to make you think about how you tackle this scenario and may change your practice.