Can a negative canthal tilt be fixed with fillers?

There have been some elegant studies performed in response to the misconceptions about fillers and their ability to lift the face.  The short answer is that fillers will increase volume but they will not lift any part of your face or neck.  The tail of the brow may be the only exception as there is a slight "lift" with placement of filler in this area often times in conjunction with neurotoxin.  Fillers can support facial tissue so areas like the corners of your mouth can be supported to not look down, but they are not really lifted.  The same might be applicable to the corners of your eyes.  

Thanks for the question.  I wouldn’t think fillers alone would lift the outer corner of the eyelids.  I would most likely think plicating the outer orbicularis to the lateral rim periosteum would help

Fillers do not reliably and permanently change eyelid position. What you are describing is lower eyelid retraction surgery with canthoplasty and possibly lateral brow lift. Best to have personal consultation to determine.