From the photo, I can see a clear separation in the eye which is consistent with your concern. Since I can't determine your exact age from your photo, I can share the causes of loosening of the lower eyelid. As we get older, it is common for the lower eyelid tone to get stretchy, soft and saggy. If you’re younger and you developed this problem, it’s related to allergies and eye rubbing. Basically, chronic rubbing of the eye can cause some stretching and some loosening. Even people who wear contact lenses who typically pull their eyelid down to manipulate and place their lenses can get some loosening. To solve this, we have to do some tightening procedure in the lower eyelid.
What I find most of the time is that there is loosening of a structure called the lateral canthal tendon. When that tendon gets loose, we do a procedure where the tendon which has been previously attached firmly to the bone is reattached. In most situations, we do something called a lateral tarsal strip where we attach the eyelid to the internal aspect of the bone using some fine sutures and it heals and lasts a long time.
I suggest that you meet with an eyelid specialist or an oculofacial plastic surgeon just to be sure that there is no other systemic issue. We want to be sure that the muscle tone is not indicative of some other problem. Once you’ve eliminated other systemic problem, then the repair for this type of problem can push through. I hope that was helpful to you, and thank you for your question.