Forehead Lines and Drooping Eyelids: Why They Develop (The Evolution of EBD VIII)
The full text of my column published in the January 2025 issue of D&PS.
Why does aging show up so early on the forehead and around the eyes?
Some changes are noticeable even to people who pay little attention to their appearance, such as middle-aged and older men. Their eyelids droop, lines develop across the forehead and between the brows, and the skin beneath the eyes wrinkles as fat bulges and grooves deepen. The tissues around the eyes are especially thin, which is why aging becomes visible here so early.
In “Fractional CO₂ Laser Resurfacing of Photoaged Facial and Non-facial Skin: Histologic and Clinical Results and Side Effects,” Gordon Sasaki and colleagues report a skin thickness of 1.17 mm on the forehead and 1.42 mm on the cheeks, compared with just 0.34 mm on the eyelids: 0.13 mm of epidermis and 0.215 mm of dermis.
The eyelids are particularly susceptible to age-related skin degeneration as dermal collagen and hyaluronic acid decline. Two defining features of aged skin are fragmentation of the dermal collagen matrix and impaired fibroblast function. Matrix metalloproteinases break up the collagen matrix. Fibroblasts attached to fragmented collagen cannot produce collagen effectively and themselves collapse. These collapsed cells make less collagen and more collagen-degrading enzymes. Once substantial collagen has been lost, this creates a self-perpetuating cycle of aging.
Overall, the brows gradually descend, lose volume, and settle toward the orbit. Wrinkling over the lateral orbital rim makes temporal hooding more prominent. One contributing factor is that the medial two-thirds of the eyebrow is relatively firmly attached to the periosteum, whereas the lateral third is not. Gravity, volume loss, reduced skin elasticity, and degeneration of connective tissue all contribute to dermatochalasis, or excess, lax eyelid skin. Lymphedema may also play a role.
Even as eyelid skin degenerates, the orbicularis oculi remains intact, with no change in muscle-fiber size. Dermatochalasis narrows the eyelid opening, and excess skin hanging over the lashes pushes them downward. When the eyelid elevator droops, redundant upper-eyelid skin hangs over the lowered lid. Loss of the central, or preaponeurotic, fat pad deepens and raises the upper-eyelid sulcus, making the area above the eye look more hollow.
Figure 1. Cross-section of the upper eyelid. Source: https://www.ophthalmologyreview.org/bcsc-fundamentals/eyelid-anatomy.
How do forehead lines, brow descent, and drooping eyelids develop?
As the forehead, brows, and eyelids become more lax with age, gravity has a greater effect. The frontalis works to lift the descending brows, creating horizontal forehead lines. Let us also consider glabellar frown lines, one of the most common reasons people seek aesthetic treatment. The brow depressors include the corrugator supercilii, with its oblique medial head and lateral transverse head, along with the procerus, orbicularis oculi, and depressor supercilii.
These muscles receive their motor supply from branches of the facial nerve, cranial nerve VII, which travel alongside the facial musculature. As the facial nerve crosses the zygomatic arch, it divides into four to eight branches that follow three main routes. The upper route runs within the temporoparietal fascia toward the frontalis and enters its undersurface. The lowest branch supplies the orbicularis oculi, and the middle branch supplies the superolateral orbicularis and corrugator. The angular nerve, continuing from the zygomatic and buccal branches, emerges beneath the zygomaticus major and supplies the medial depressors, including the medial oblique head of the corrugator, the procerus, and the depressor supercilii.
Unlike the motor nerves, which run alongside the facial muscles, sensory branches of the trigeminal nerve, cranial nerve V, emerge from foramina proximal to the depressor muscles and pass perpendicularly through this muscle group. After emerging through the muscles, they run parallel to the soft tissues.
It helps to consider medial and lateral brow descent separately. Medial descent is strongly influenced by the depressor supercilii, procerus, and orbicularis. Lateral descent is affected by the orbicularis and the transverse head of the procerus, as well as eyelid weight, brow fat, and the soft tissues of the forehead.
The orbicularis oculi is the main muscle that closes the eye. Like the frontalis and other muscles of facial expression, it is supplied by the facial nerve, cranial nerve VII. It has three parts: the tarsal portion over the tarsal plate, the septal portion over the orbital septum, and the orbital portion over the outer bony orbital rim. The levator palpebrae superioris, which opens the eye, is supplied by cranial nerve III. The eyelid crease depends on the level of attachment to the tarsal plate and where the fibers extending from it pass through the orbicularis to attach to the skin.
Figure 2. Muscles around the brow. Source: https://www.ophthalmologyreview.org/bcsc-fundamentals/eyelid-anatomy.
The orbital septum is a thin sheet of fibrous connective tissue arising from the orbital rim. In Koreans and other Asian populations, it usually attaches to the levator fascia. With age, the septum thins, stretches, and weakens, allowing orbital fat to protrude toward the eyelid. Aging around the eyes involves changes in bone, loss of soft tissue, tissue descent, and changes in the skin. Eyelid laxity, upper-eyelid and brow descent, and lacrimal gland prolapse are among the resulting features.
Skin aging occurs across the face but is particularly apparent around the eyes. As collagen declines, the skin loses elasticity, becomes thinner, and develops more wrinkles. Both external factors, such as UV exposure and smoking, and intrinsic aging contribute to these changes.
In “Volumetric Rejuvenation of the Periorbital Region,” Mark Glasgold and colleagues show photographs of the same woman taken 37 years apart. Her facial contour changes from oval to flatter with age. In youth, the eyes look long and full, the bony orbital outline is not visible, the skin is elastic, and the upper-eyelid crease is barely apparent. With age, hollowing beneath the forehead and at the temples creates shadows. The upper lid loses its fullness, and its crease deepens.
In “Volumizing the Brow with Hyaluronic Acid Fillers,” Lambros compares photographs at ages 21 and 64. Eyes that once looked long and full become rounder and shorter. Before-and-after photographs of a 45-year-old woman undergoing blepharoplasty show that removing excess skin and fat actually worsened the hollow appearance around her eyes. After local anesthetic was injected, the older, rounder, shorter appearance temporarily changed to the longer, fuller appearance associated with youth.
How do the bone, fat, and skin around the eyes change with age?
Age-related bony changes around the eyes arise as bone remodels and the orbital space expands. Building on Lambros's hypothesis, Pessa described enlargement and vertical elongation of the orbital aperture, with scalloping at the superomedial and inferolateral orbit, in “An Algorithm of Facial Aging: Verification of Lambros's Theory by Three-dimensional Stereolithography, with Reference to the Pathogenesis of Midfacial Aging, Scleral Show, and the Lateral Suborbital Trough Deformity.”
Distortion of the superomedial orbital contour contributes to increased fullness of the medial upper-eyelid fat. These bony changes allow brow soft tissue to descend toward the orbital opening, producing brow ptosis and lateral orbital hooding. As the orbital bones remodel and the opening expands, the upper-eyelid sulcus deepens; the eyes may look hollow and the eyelids may droop with age.
Pessa and colleagues studied the skeletons of 30 men divided into three age groups. They found that orbital width and height did not change with age, but the curves at the superomedial and inferolateral orbit became distorted. They attributed this to selective bone resorption and remodeling. Pessa linked these skeletal changes to changes in the overlying soft tissues, explaining that together they accentuate the tear trough and scleral show.
Figure 3. Example of skeletal changes in the orbital shape and restoration of youthful contour with an orbital rim implant. Source: Overview of Current Thoughts on Facial Volume and Aging, D. Kahn et al., September 2010, Facial Plastic Surgery: FPS, DOI:10.1055/s-0030-1265024.
By following and comparing patient photographs over many years, Lambros and colleagues described changes in the aging upper face. The eyebrows descended slightly, and the peak of the upper eyelid moved laterally. The medial canthus stayed in place or shifted medially, while the lateral canthal angle moved inward, ultimately shortening the horizontal eyelid opening. Other changes included hollowing of the temples and adjacent periorbital areas, forehead lines, upper-eyelid ptosis, and dermatochalasis.
Lateral brow descent is common in periorbital aging. Some studies attribute it to inadequate support against gravity in the soft tissues lateral to the temporal fusion line. Others, however, report the paradoxical finding that brows rise rather than fall with age. This elevation is accompanied by horizontal forehead lines and increased frontalis activity. Possible explanations include the stage before acquired ptosis becomes apparent, sustained frontalis compensation for eyelid aponeurosis dehiscence, and habitual brow elevation to keep excess skin from obstructing vision.
What causes age-related eyelid ptosis?
Age-related ptosis arises from levator dehiscence, involving weakening of the medial aponeurosis, lateral displacement of the upper tarsal plate, and fatty degeneration of the levator. Muscles have commonly been assumed to become more lax with age. Some studies, however, suggest that the muscles controlling the brows increase their resting tone to adapt to redistribution of the underlying volume.
Fat in the forehead, temples, and midface loses volume and descends with age. Loss of retro-orbicularis oculi fat, or ROOF, leaves redundant, sagging skin. Temporal hooding caused by forehead descent must be clearly distinguished from lacrimal gland prolapse. Within the orbit, medial upper-eyelid fat paradoxically increases while the central, preaponeurotic fat decreases. Lower-eyelid fat, by contrast, increases with age. To assess upper-face aging and treatment results objectively, measurements such as those in Figure 4 are used: tarsal platform show (TPS), brow fat span (BFS), and margin reflex distance (MRD), the distance from the light reflex at the center of the pupil to the upper-eyelid margin.
Figure 4. Top: measurement of brow fat span (BFS), tarsal platform show (TPS), and margin reflex distance (MRD1) on standardized photographs, with corneal diameter set at 11.5 mm for scale. Bottom: in the same patient following left ptosis surgery and bilateral asymmetric blepharoplasty, TPS symmetry has improved and BFS has shortened. Source: Cosmetic Outcome of Posterior Approach Ptosis Surgery (An American Ophthalmological Society Thesis), Robert A. Goldberg et al., Trans Am Ophthalmol Soc. 2011 Dec;109:157–167.
How can forehead lines and wrinkles around the eyes be treated?
Microneedle RF has attracted interest because it can produce several treatment effects at moderate power levels; it does not require the output used in monopolar RF. Initially used mainly for acne, pores, and scars, it is now also used for pigmentation concerns such as melasma. There were reasons it had not previously been practical for lifting. At energies sufficient for lifting and tightening, excessive coagulation around the needles and substantial epidermal injury limited energy delivery. Reaching an adequate depth was another limitation.
VIRTUE RF addresses these problems with subpulse technology and a cooling plate. The pulse can be divided into as many as 10 subpulses to limit excessive coagulation. Cooling reduces epidermal injury, allowing more energy to reach deeper tissues.
Microneedle RF delivers radiofrequency energy through insulated fine needles inserted into the skin. The needles create tiny channels and deliver energy directly into the dermis. Current flows between the needles, heating the tissue and stimulating collagen production and tissue repair. This is how the treatment improves skin elasticity and texture.
VIRTUE RF develops this microneedle RF approach further. It allows adjustment of up to 10 subpulses and uses a cooling plate to enhance the effects of existing treatments, adding lifting as a new indication. How does it differ from earlier microneedle RF devices? Most conventional devices use a single pulse or up to five pulses. Dividing the pulse into as many as 10 allows more precise, effective treatment, encouraging greater collagen production and better results.
Increasing the number of subpulses reduces coagulation around each needle while increasing non-necrotic thermal injury between the needles. This encourages more collagen production and improves skin elasticity and texture. Subpulse technology also reduces pain, making treatment more comfortable. Limiting excessive thermal injury shortens recovery and reduces adverse effects. Put simply, dividing the pulse into as many as 10 subpulses directs more of the energy toward collagen production instead of expending it on coagulation. It is a more efficient use of energy.
The cooling plate controls heat during treatment, reducing pain and limiting epidermal injury. This allows higher energy delivery with greater safety and substantially shorter recovery. Contact with the plate briefly lowers skin temperature. Cooling increases impedance, and electrical current tends to follow the path of lower impedance. RF energy can therefore pass through the epidermis more readily to reach the deeper dermis. Moving energy into deeper layers instead of leaving it concentrated in the epidermis increases its treatment effect.
(To be continued in the next issue)
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