title: Volumetric considerations for lower eyelid and midface rejuvenation.
abstract: OBJECTIVE
  With the accepted understanding of volume loss as one of the main factors in facial aging, oculofacial surgeons are embracing the concept of 'removing' less and 'filling' more. The purpose of this review is to present an update of the different alternatives and techniques for lower eyelid and midface restoration/rejuvenation using filler agents.
  
  
  RESULTS
  When a filler agent is chosen, the aim is to provide some lift, support and sculpting to the treated area. Nonpermanent or semi-permanent fillers are most widely accepted by physicians mainly because there is a lower possibility of complications. The involutional changes in the facial structures are a continuous process; this requires reassessment and variation in techniques in addition to choosing different products at different ages. Safety, support capability, ease of injection and cost are the factors to consider when choosing an injectable implant. But, physicochemical structure or rheological properties, such as viscosity and elasticity, enable the clinician to objectively select the most appropriate injectable implant depending on the specific anatomical area. An injectable with low viscosity may be ideal for lip enhancement wherein softness is required, whereas a higher viscosity filler or a harder filler may be better indicated for structure and support in the midface.
  
  
  CONCLUSIONS
  Given the wide variety of filler materials available, clinicians and surgeons must be able to select products based on safety, lifting or sculpting capability and rheological properties, such as viscosity and elasticity. These factors provide an objective parameter of how the filler agent will perform in a specific area.
authors.affiliation: Ophthalmology Department, University of Puerto Rico, School of Medicine, San Juan, Puerto Rico, USA. jrmontespr@aol.com
authors.forename: José R
authors.initials: JR
authors.lastname: Montes
mesh_terms: D019882:Blepharoplasty / Q000379:methods; D003357:Cosmetic Techniques; D005143:Eyelids / Q000601:surgery*; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D012060:Rejuvenation; D015361:Rhytidoplasty / Q000379:methods*; D015595:Skin Aging / Q000187:drug effects*
chemical_list: C526061:Juvederm Ultra; D006820:Hyaluronic Acid; C445361:Restylane