When patients use tape or glue on their eyes to create a double eyelid fold, they are creating a fold by connecting skin to skin. This method does not induce any weight on the eye muscle. In contrast, surgery is connecting the skin to eye elevating muscle (levator muscle). Therefore, in a double eyelid surgery, extra weight, which is the eyelid skin, superficial orbicularis oculi muscle and soft tissue burdens the levator muscle.
For patients with weak eyelid muscle function, the eyelid muscle does not fully lift to create a double eyelid fold even though the tape or glue has been applied on the eyelid skin. So, unless the eyelid muscle function is excellent, the ptosis repair should be performed at the time of double eyelid surgery. In summary, just because use of tape or glue creates a certain look, the surgical result may not reproduce the same look because the mechanism of the effect of the tape versus surgery is different (skin to skin connection vs. skin to muscle connection).
Lastly, the use or tape or glue, will result in skin irritation, and thus is not a good long term solution.