I don't know if the crying could cause an increase in corneal thickness, but it is possible that the other, thinner measurement resulted from some corneal dehydration. The bottom line is that these measurements somewhat can vary with the technique used and with the technician. If you are considering LASIK, the pachymetry measurement (corneal thickness) should be repeated; the surgeon needs to be confident in the accuracy of the reading, and in its stability.
Thank you for your reply. At around the time I had the first measurement taken, I had been using Opticrom eye drops for Giant Papillary Conjunctivitis. The active ingredient in Opticrom is sodium cromoglicate. Do you think these eye drops could have caused dehydration of my cornea and therefore a thinner corneal thickness reading?
I am not aware of that association, but the measurements should be repeated until they are stable and reproducible. Measure twice (or more!) and cut once.