Why is a "Drill hole" canthopexy done?

What will make the result last longer is not drill hole but rather proper release of the lower eyelid ligaments using internal lower eyelid retraction surgery. Of course, best to have evaluation in consultation for proper treatment plan. See an expert oculoplastic surgeon.

The placement of drill holes is a common technique for getting a new lateral canthal position high up inside the orbital rim. It is usually used for more severe cases of lower lid retraction or when significant lateral eye corner elevation is needed. It is not usually done for a lateral canthopexy or when lesser counts of corner adjustment are needed or as a protective maneuver in some lateral blepharoplasty procedures. But how these statements apply to your case and the need for its use must be based on physical examination and your specific eyelid needs.