Thickness of human cornea measured by topographic pachometry.
In the hands of trained user, the topographic pachometer proves to be  an instrument of acceptable clinical precision (standard deviation = 0.006mm). An examination of corneal thinning during waking hours revealed a rate of thinning which was greatest upon lid opening and which declined  uniformly throughout the day (p = 0.01). An investigation into menstrually related change in corneal thickness revealed that at least 122 subjects would be required to investigate this change on an acceptable statistical basis (p = 0.05).
D003315:Cornea / Q000502:physiology*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008598:Menstruation; D009907:Optometry / Q000295:instrumentation*; D013997:Time Factors