Does pupil dilation change the measurement for astigmatism?

[Jim_in_Italy]

In trying to understand why my astigmatism has increased after a corneal abrasion, I was given to understand that measuring for astigmatism with and without drops to dilate the pupil, will give different results. The astigmatism reading will appear to be lower with pupil dilation. (What are the scientific or Latin terms used to measure “wet” and “dry” ?) I tried to google to find these answers and came up with nothing. Dr Hagan, if you are reading, could you direct me to a good explanation, So as not to take up your time? The obvious question is, assuming dilation gives a different result, which is the more accurate? Dry, undiluted, or wet dilated with drops? Many thanks

[JohnHaganMD]

All tests have variability,  K-readings (keratometry) is no exception.  Generally speaking the K readings should not be affected by pupil size.  Tests on the back of the eye B-scans, A-scans,  OCT and fluorsciene angiography are affected by pupil size being more accurate in larger pupil.  The other reason is the cornea is still changing as healing progresses. That's really all I can comment.