Sounds to me like unless you had an injury to the area that this was always the case from birth? There are bone diseases that cause growing of the skull and bones abnormally (Paget's disease) but this would have more signs in other areas. Also this is normally an enlarging of the skull. Unfortunately Physio won't move an eye socket that is at a different height to the other side. You should be clear though on whether the eye itself is different (with a level head) or wdether the different in tone of your eyelids are causing the appearance of one eye being lower than the other. This is as there are several reasons for droopy eyelids or ptosis. See more on that here Ptosis