I have a question regarding the refraction put in for pre op info. We've noticed that if you change the pre op refraction, the IOL power/outcome changes. So, how do we know what refraction to put in? What if the patient has a huge myopic shift? Or if it's a mature/hypermature cataract and no refraction or retinoscopy was able to be obtained? What do you recommend?

You should put in the Refraction before it was affected by the cataract … oldest pair of glasses, old refractive records, history,, etc.

There is some question as to whether you use the oldest known refraction or the current refraction (on pre-op form) for the lens calculation. Would you please tell me why you would choose one over the other if it matters.

It does matter and you should use the Refraction before it was affected by the cataract (old glasses).

When we enter pre operative data for a patient the K readings come from the IOLmaster. When we enter our post operative K readings these typically come from an autorefractor. Since the two K readings are from different types of instruments and they measure different sized surface areas would this effect our optimization?

It does not affect the Personalized Lens Constant (PLC), but will affect the SIA (surgically induced astigmatism). This is used for Toric IOLs and would make a difference, but not sure how much. Get 10 or 15 Ks on both and look at the difference.