Pretarsal fat compartment in the lower eyelid

It is generally accepted that there are three infraorbital fat regions in t he lower eyelid; medial, central, and lateral compartments. However, removi ng only the fat in the lateral compartment does not remove the bulge just b elow the eyelashes, which is caused by another fat pad. The aim of this stu dy was to describe the anatomy of the pretarsal fat compartment and to demo nstrate its: clinical implications in lower lid blepharoplasty. Ten cadaver s (total 20 lower eyelids) were studied. A skin-muscle flap was reflected t o expose the soft pretarsal structures. A small stab incision was made on t he lateral portion of the sac containing fat on the tarsus. Methylene blue dye was injected into the sac. Specimens were fixed and sagittal sections i n four different planes were prepared for histological analysis. The inject ed dye remained within the sac and demarcated it as a pear or cone shaped s tructure. This encapsulated fat compartment sits on the lateral half of the tarsal plate above the lateral compartment fat. Auxiliary or submuscular f at is well known. This study, however, designates the pretarsal fat as ''en capsulated" in a compartment instead of being unbound. We have named it the "pretarsal fat compartment." Histologically, orbital septal fibers separat e "pretarsal fat" from lateral infraorbital fat. It is recommended that fat in the pretarsal fat compartment be removed during lower lid blepharoplast y in order to alleviate thc bulge or knoll of the skin just below the lower eyelashes. (C) 2001 Wiley-Liss, Inc.