The term "under-eye hollows" is best avoided. Why? "Under" is too imprecise and can be used to indicate anything from eyelid hollowness to cheek bone depression to midface descent to dark circles, all of which are different conditions requiring different treatments.
Essentially, the lower eyelid begins at the eyelashes and ends just above the rim of bone beneath the eye. Below that bony rim sits the top of the cheek. The anatomy of these two structures is distinct.
Imprecise terminology is confusing and can, unfortunately, result in incorrect treatment. The terms below are preferable:
• Orbital Hollowness: Volume deficiency of fat within the orbit (the space inside of the bony eye socket)
• Eyelid Hollowness: Since the eyelid itself contains no real fat pockets of its own but is instead inflated from behind by the forward projection of orbital fat, this term is synonymous with "orbital hollowness."
Since the cause of eyelid hollowness is an orbital volume deficiency, "orbital hollowness" is the most accurate and thus preferred designation.
• Cheek Hollowness: An indentation at the topmost area of the cheek located just below the bottom of the eyelid. Cheek hollowness is caused by the descent of cheek tissue and/or poor bony formation below the eyelid (maxillary hypoplasia). While located adjacent to the eyelid, the cheek is not the same as the eyelid and treatments directed at treating hollowness in one area do not improve on the other. If bone can be felt directly under the area of hollowness, the location of the problem is the upper cheek rather than the eyelid or orbit.
• Midface Descent: Essentially, a downward migration of the cheek
• Tear Trough: Technically, the "nasojugal fold," which is a normal anatomical area of concavity located between the nose and upper rim of the cheek. If overly deepened, the state may be described as a "tear trough deformity" or "tear trough hollow."
This is an example of "upper cheek hollowness" and not an eyelid/orbital problem per se.
• Infraorbital Hollowness: Another term for upper cheek hollowness
• Maxillary Hypoplasia: Inadequate development of the bony rim of the eye socket and upper cheek. In the presence of a prominent eye, this condition may give the appearance of substantial lower eyelid hollowness and yet is not an eyelid condition per se.
The most effective method to treat true orbital/eyelid hollowness is with true fat grafting.
On the other hand, cheek hollowness may be treated with a wide variety of techniques ranging from fat injection to midface lift to the placement of synthetic implants to the injection of temporary commercial filler substances.