Aging of the periorbital and midface complex is a dynamic, multifactorial, and inevitable process. This article reviews the morphologic changes that occur in the aging midface and discusses the pathogenesis of midfacial and lower eyelid aging based on its anatomic components, from the craniofacial skeleton to the skin surface.
Key points
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Facial aging is a complex, multi-factorial process that is frequently debated.
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Facial changes occur at multiple points including skeletal, dentition, adipose tissue, SMAS, ligaments, and skin.
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There are both volumetric and gravitational theories of aging.
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Understanding of midfacial and lower eyelid aging is key to surgical rejuvenation and reconstruction.
“Maybe it’s true that life begins at fifty. But everything else starts to wear out, fall out, or spread out.”
Overview
Aging of the periorbital and midface complex is a dynamic, multifactorial, and inevitable process. Although many of the changes that occur are at the cellular level and may be related to anatomic, biochemical, and genetic factors, on the surface the changes that are visible to others actually give the impression of facial aging. Exogenous and endogenous factors can have a significant impact on this perception. Solar exposure, cigarette smoking, medications, alcohol use, body mass index, and endocrinologic status have all been implicated as factors that accelerate both cutaneous and subcutaneous aging. These factors, when combined with others, act together to create the vicissitudes of facial aging.
Although individuals all change over time in different ways, most of the aging changes that occur in the midface occur in a predictable fashion. These predictable changes typically begin to appear in the middle of the fourth decade. Degenerative changes occur in nearly every anatomic component of the midface and include cranial bone remodeling, tissue descent secondary to gravity, fat atrophy, and deterioration in the condition and appearance of the skin. Patients often seek consultation for facial rejuvenation in the areas of the lower eyelids and adjacent tissues. They often present because they or others notice that they look “tired,” due to changes in the area under their eyes. Studies have shown that people infer age based on visual cues from around the eyes. Age-related changes in the periorbital tissues, under-eye bags, and wrinkles have a significant impact on the perceived age of an individual.
This article reviews the morphologic changes that occur in the aging midface and discusses the pathogenesis of midfacial and lower eyelid aging based on its anatomic components, from the craniofacial skeleton to the skin surface.
Morphology
Changes that occur in the periorbital region and the cheek are responsible for the appearance of facial aging. A youthful eye has the following characteristics:
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An upward slant from the medial to lateral canthus
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Lower lid position 1 to 2 mm above the inferior edge of the limbus
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A smooth, blended curve at the lid/cheek junction where the concavity of the lower eyelid is minimal and meets the full convexity of the cheek
A youthful cheek or midface has the following characteristics:
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The cheek in youth is volumized, appearing round, and the malar prominence is covered by malar fat.
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The overall shape of the youthful midface is heart-shaped in appearance with the point of the “heart” at the chin, and the prominences over the zygomatic arch extending to the inferolateral orbit.
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Direct overhead light does not create shadows at the eyelid/cheek junction in youth—the fullness of the lateral cheek reflects light.
- •
When viewed at an oblique angle (three-quarter view, including visualization of both medial canthi), a youthful face has an S-shaped curve, starting with the convexity at the brow, which tapers to the concavity of the orbital wall, then once again transitions into the convexity of the upper midface, ending at the concavity of the lower midface.
This double curve of the brow and midface flattens with increased age. Ramirez and Volpe termed this curve the double ogee.
During the fourth decade of life, aging changes begin to affect the midface and produce characteristic changes as the aesthetic subunits start to lose their homogeneity:
- •
The lateral nasal wall loses its smooth transition over the anterior maxilla and becomes convex.
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Orbicularis rolls appear in the pretarsal eyelid, along with fine rhytids in the lateral canthal area.
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A nasojugal groove, termed the tear trough , forms below the lower eyelid, and the nasolabial fold grows in length and depth.
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The skin loses luster and becomes overall more sallow, pigmented, coarse, and wrinkled.
- •
These grooves, rolls, and wrinkles begin to create shadowing, particularly noticeable in overhead light, which creates the appearance of facial aging.
These changes, all related to the interplay of light and shadow and the reflection and luminance of the skin, are instantaneously and instinctively processed at visual cortical levels—aging is apparent to everyone with whom one comes into contact.
During the fifth decade of life and beyond, further changes continue to occur:
- •
Protrusion of the temporal, nasal, and central lower eyelid fat pads causes bulges to appear below the lower eyelid.
- •
The tear trough elongates laterally and continues to descend medially, and the inferior orbital rim becomes visible.
- •
A hollow develops in the centromedial cheek below the tear trough, termed the V deformity .
- •
The cheeks lose their projection and descend.
- •
Redundancies at the inferior margin of the orbicularis, termed festoons , may appear in the midcheek.
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The nasolabial fold deepens as the mass of the midface appears to migrate inferiorly and nasally.
- •
The corners of the lip become down-turned, as though weighed down by the ptotic midfacial fat.
- •
Melomental folds, known as marionette lines, develop.
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The heart-shaped face of youth gradually becomes squared off and eventually, after further midface descent, becomes pear-shaped ( Fig. 1 ).
Fig. 1
Attributes of a old versus young face. This shows descent of the malar fat pat in the transition from a heart-shaped youthful face to a pear-shaped aging face.
Overview
Aging of the periorbital and midface complex is a dynamic, multifactorial, and inevitable process. Although many of the changes that occur are at the cellular level and may be related to anatomic, biochemical, and genetic factors, on the surface the changes that are visible to others actually give the impression of facial aging. Exogenous and endogenous factors can have a significant impact on this perception. Solar exposure, cigarette smoking, medications, alcohol use, body mass index, and endocrinologic status have all been implicated as factors that accelerate both cutaneous and subcutaneous aging. These factors, when combined with others, act together to create the vicissitudes of facial aging.
Although individuals all change over time in different ways, most of the aging changes that occur in the midface occur in a predictable fashion. These predictable changes typically begin to appear in the middle of the fourth decade. Degenerative changes occur in nearly every anatomic component of the midface and include cranial bone remodeling, tissue descent secondary to gravity, fat atrophy, and deterioration in the condition and appearance of the skin. Patients often seek consultation for facial rejuvenation in the areas of the lower eyelids and adjacent tissues. They often present because they or others notice that they look “tired,” due to changes in the area under their eyes. Studies have shown that people infer age based on visual cues from around the eyes. Age-related changes in the periorbital tissues, under-eye bags, and wrinkles have a significant impact on the perceived age of an individual.
This article reviews the morphologic changes that occur in the aging midface and discusses the pathogenesis of midfacial and lower eyelid aging based on its anatomic components, from the craniofacial skeleton to the skin surface.
Morphology
Changes that occur in the periorbital region and the cheek are responsible for the appearance of facial aging. A youthful eye has the following characteristics:
- •
An upward slant from the medial to lateral canthus
- •
Lower lid position 1 to 2 mm above the inferior edge of the limbus
- •
A smooth, blended curve at the lid/cheek junction where the concavity of the lower eyelid is minimal and meets the full convexity of the cheek
A youthful cheek or midface has the following characteristics:
- •
The cheek in youth is volumized, appearing round, and the malar prominence is covered by malar fat.
- •
The overall shape of the youthful midface is heart-shaped in appearance with the point of the “heart” at the chin, and the prominences over the zygomatic arch extending to the inferolateral orbit.
- •
Direct overhead light does not create shadows at the eyelid/cheek junction in youth—the fullness of the lateral cheek reflects light.
- •
When viewed at an oblique angle (three-quarter view, including visualization of both medial canthi), a youthful face has an S-shaped curve, starting with the convexity at the brow, which tapers to the concavity of the orbital wall, then once again transitions into the convexity of the upper midface, ending at the concavity of the lower midface.
This double curve of the brow and midface flattens with increased age. Ramirez and Volpe termed this curve the double ogee.
During the fourth decade of life, aging changes begin to affect the midface and produce characteristic changes as the aesthetic subunits start to lose their homogeneity:
- •
The lateral nasal wall loses its smooth transition over the anterior maxilla and becomes convex.
- •
Orbicularis rolls appear in the pretarsal eyelid, along with fine rhytids in the lateral canthal area.
- •
A nasojugal groove, termed the tear trough , forms below the lower eyelid, and the nasolabial fold grows in length and depth.
- •
The skin loses luster and becomes overall more sallow, pigmented, coarse, and wrinkled.
- •
These grooves, rolls, and wrinkles begin to create shadowing, particularly noticeable in overhead light, which creates the appearance of facial aging.
These changes, all related to the interplay of light and shadow and the reflection and luminance of the skin, are instantaneously and instinctively processed at visual cortical levels—aging is apparent to everyone with whom one comes into contact.
During the fifth decade of life and beyond, further changes continue to occur:
- •
Protrusion of the temporal, nasal, and central lower eyelid fat pads causes bulges to appear below the lower eyelid.
- •
The tear trough elongates laterally and continues to descend medially, and the inferior orbital rim becomes visible.
- •
A hollow develops in the centromedial cheek below the tear trough, termed the V deformity .
- •
The cheeks lose their projection and descend.
- •
Redundancies at the inferior margin of the orbicularis, termed festoons , may appear in the midcheek.
- •
The nasolabial fold deepens as the mass of the midface appears to migrate inferiorly and nasally.
- •
The corners of the lip become down-turned, as though weighed down by the ptotic midfacial fat.
- •
Melomental folds, known as marionette lines, develop.
- •
The heart-shaped face of youth gradually becomes squared off and eventually, after further midface descent, becomes pear-shaped ( Fig. 1 ).
Fig. 1
Attributes of a old versus young face. This shows descent of the malar fat pat in the transition from a heart-shaped youthful face to a pear-shaped aging face.
Periorbit and lids
The initial sign of midfacial aging, the tear trough, often occurs in the lower eyelids as a hollow immediately below the lower eyelid fat prominences. As described by Loeb, the pathogenesis of the tear trough is due to 3 coexisting anatomic factors:
- 1.
The solid fixation of the orbital septum to the inferomedial arcus marginalis
- 2.
A triangular gap formed by the junction of the orbicularis oculi, medial lip elevators, and levator alaeque nasi
- 3.
The absence of fat and soft tissue from the central and the medial fat pads subjacent to the inferior orbicularis oculi
Tear Trough
Some investigators believe that the major contributing factor in the tear trough deformity is the lack of fat at the level of the inferior arcus marginalis, as demonstrated by intraoperative and cadaveric dissections of individuals with and without a tear trough convexity. More recent cadaveric dissections have shown that the prominence of the tear trough has its anatomic origin in a true osseocutaneous ligament, termed the tear trough ligament . This ligament is found between the origins of the palpebral and orbital parts of the orbicularis oculi and arises from the maxilla to insert into the skin at the exact location of the tear trough.
Fat Protrusion
Protrusion of fat in the lower eyelids becomes more apparent with age. Hamra referred to the alterations in the contour of the lower eyelid at this point of chronologic aging as the “double convexity deformity,” which occurs as bulging lower eyelid fat is juxtaposed to the hollow of the tear trough. Controversy surrounds the possible causes of this increased fat prominence. Potential causes include orbital fat pseudoherniation and an increase in the amount of lower eyelid adipose tissue. In a study of orbital and facial CT images from 167 patients, Chen and colleagues demonstrated that lower eyelid orbital fat herniation occurred with chronologic aging. Attenuation of the orbital septum may contribute to the appearance of pseudoherniation. de la Plaza and Arroyo suggested that distension of orbital supporting structures, such as the orbital septum, capsulopalpebral fascia, and lateral canthal tendon, leads to descent of the globe with resultant compression and anterior displacement of inferior orbital fat. Alternatively, downward stresses on the orbital septum by the volumes of the midface may bring forward the septum and the fat immediately posterior to it, thus increasing the visibility of the lower eyelid fat compartments.
Periorbital fat may gain prominence because orbital fat increases with aging. Darcy and colleagues analyzed orbital MRIs in 40 patients and demonstrated that orbital fat expansion occurs with age, displacing the soft tissues of the lower eyelid anteriorly. These findings may be misleading because single MRI cuts were used to extrapolate orbital volume. The investigators postulated that adipocyte hyperplasia/hypertrophy or chronic fluid accumulation with age caused the orbital fat volume to increase.
Midfacial Fat Descent
In all likelihood, the most important change that occurs in the lower eyelids is the unveiling of deep eyelid contour that results from descent of midfacial fat and focal volume loss at the inferior orbital rim. The orbital opening appears to enlarge vertically as the midface volumes descend and exert downward traction on the septum and arcus marginalis, exposing the tear trough and eventually the inferior orbital rim. Lower eyelid fat becomes prominent due to the absence of the malar fat that covers it in youth.
Midface skeleton
As aging progresses, vertical and horizontal projection of the midface are lost, resulting in a “collapse” of the bony midface. The inferior orbital rim remodels, resulting in an increase in the vertical height of the orbit. The bony maxilla below the rim loses projection and the pyriform aperture recesses posteriorly. Studies of normal CT scans throughout life show that these changes in the orbital rim and maxilla are predictable. Involution of the skeletal elements of the midface becomes more prominent in the sixth decade and is observed more commonly in women than in men. Glowacki proposed that increased bone resorption during perimenopause might contribute to the greater degree of bony involution observed in women.
Studies using 3-D CT reconstructions found a significant increase in the orbital aperture and width correlated to advancing age in both male and female patients. These results were corroborated in a review of consecutive facial CT scans in 50 women and 50 men, showing that the angles of the pyriform process and the inferior orbital rim retrude with age, whereas the anterior lower eyelid fat pads appeared to become more prominent. The investigators hypothesized that inferior and downward displacement of the orbital rim may pull the orbital fat anteriorly due to “shared attachments of the orbital septum and lower eyelid retractors.” They also speculated that this inferior displacement exerts downward traction on the lower eyelid, resulting in the relative lower eyelid retraction seen with aging.
In a study of facial CT images from 30 male patients, Pessa and colleagues showed that the maxilla vertically shortened in proportion to the orbit with aging and attributed these changes to skeletal remodeling.
The investigators proposed that the enlarged orbital aperture in combination with the shortened vertical maxilla results in a relative decrease in the surface area available in the midface to support overlying soft tissues. This phenomenon was termed, the concertina effect , due to the decreased ability of the bones to support and volumize the overlying soft tissues ( Fig. 2 ). Another study also by Pessa and colleagues demonstrated that the globe becomes relatively proptotic with respect to the aging alterations of the inferior orbital rim and the cheek mass due to bone loss.
Dentition
Changes in dentition may secondarily affect overall bony changes and thus contribute to changes in the midface. Loss of dentition in the maxilla may lead to loss of alveolar bone. Studies of human skulls have found a strong correlation with tooth loss and a reduction in facial height, especially in the maxilla and mandible. The loss of teeth alone affects the thickness of cortical bone throughout the facial skeleton, leading to significant cortical bone loss and alveolar ridge absorption in the edentulous. Edentulous patients have a loss of load-bearing stress and this may result in maxillary ridge resorption, which occurs in the craniofacial skeleton throughout life. Alternatively, the reduction of tooth vascularity with age may result in the decrease of trophic factors and could result in a decrease in metabolic demand and decreased osteoblastic activity. The loss of teeth seems to affect the mandible more than the maxilla, and more bone loss is observed in women than in men.
Periorbital and midface musculature
It is well known that aging causes a decline in muscle mass and muscle strength throughout the body. These muscular changes extend to the midface as well. The orbicularis oris thins with age, whereas the orbicularis oculi does not. Analyses of MRIs from patients of varying ages suggest that as muscles of the midface age, they act as though they are in spasm, progressively shortening and straightening. Le Louarn and colleagues have hypothesized that along with repetitive facial contractions that recur over a lifetime, this spasm may cause a prolapse of the deep midfacial fat superficially. Owsley and Roberts’s analyses of histologic specimens and MRIs of the midface suggest that repeated contractions of the levator labii during animation may produce increased tissue expansion forces in the overlying cheek fat pad, contributing to its downward migration.
Adipose tissue
Rohrich and colleagues have extensively defined the fat compartments of the face and described their clinical importance ( Fig. 3 ).
