Uneven pupil dilation in infant

I just noticed my one month old daughter's right pupil is more dilated than the left.  Both eyes dilate and constrict according to light at the same rate, just the size difference remains.  The discrepency is less than 25%, I guess.

I already called on-call MD.  Suggests to check it out on Monday (It's late Sat. night).  Still, nervous about it.  Called the nursery at hospital she was born in.  Nurse I spoke with thinks waiting to check it out on Monday is fine.  I've been searching the web to find more info - to no avail.

I don't even know what it could mean, except that it's could be serious.  Thinking about going to ER to have an MD see her.  

Anybody have any advice?  Experience?

[Ag-i-doc]

thats a tough one.  cant really tell w/o seeing her.  but *IN GENERAL* if both eyes will constrict when lights are shown at them, and both pupils dilate when in the dark, and the proportion is always the same (one 25% bigger all the time under every circumstance) then i am much less worried and monday is probably fine.