Paralytic brow ptosis
Cause: Frontalis muscle paralysis due to facial nerve palsy (cranial nerve VII)
Features: Accompanied by orbicularis oculi muscle paralysis, lower eyelid ectropion, and drooping mouth corner
Brow Ptosis
1. What is brow ptosis
Section titled “1. What is brow ptosis”Brow ptosis is a condition in which the eyebrow droops from its normal position (near or above the supraorbital rim). It is caused by decreased function of the frontalis muscle or tissue laxity, and the relative increase in excess skin of the upper eyelid becomes an important cause of pseudoptosis.
In cases of dermatochalasis, compensatory brow elevation is often present. Therefore, in the evaluation of ptosis, checking for compensatory brow elevation is an essential step.
Classification
Section titled “Classification”Brow ptosis is classified into three types based on cause.
Age-related (functional) brow ptosis
Cause: Frontalis muscle relaxation, gravitational drooping of skin and subcutaneous tissue
Features: Causes pseudoptosis. Considered the most common type
Symptomatic brow ptosis
Cause: After a long course of blepharospasm
Feature: The surrounding tissue becomes lax due to the antagonism between spasm and eyelid opening effort
| Type | Cause | Main associated findings |
|---|---|---|
| Paralytic | Facial nerve palsy → Frontalis muscle palsy | Orbicularis oculi palsy, lower eyelid ectropion, drooping mouth corner, disappearance of nasolabial fold |
| Age-related (functional) | Frontalis muscle relaxation, gravitational tissue ptosis | Pseudoptosis, increased forehead wrinkles |
| Symptomatic | Long-term course of blepharospasm | Complicated ptosis, skin laxity, difficulty opening eyes |
Epidemiology
Section titled “Epidemiology”The incidence of facial nerve palsy (Bell’s palsy) is 20–30 per 100,000 people per year. Detailed epidemiological data on the prevalence of age-related brow ptosis have not been established. In patients with blepharospasm, brow ptosis frequently occurs over the long term.
2. Main Symptoms and Clinical Findings
Section titled “2. Main Symptoms and Clinical Findings”Common Symptoms
Section titled “Common Symptoms”- Brow ptosis: descent of the eyebrow to or below the supraorbital rim
- Increased upper eyelid skin redundancy: relative increase in upper eyelid skin due to brow ptosis, causing pseudoptosis
- Superior visual field defect: Excess skin hangs over the pupil, obstructing the visual field
Clinical findings by type
Section titled “Clinical findings by type”| Clinical findings | Paralytic | Involutional | Symptomatic (spastic) |
|---|---|---|---|
| Forehead wrinkles | Absent | Decreased | Variable |
| Pseudoptosis | ++ | +++ | + |
| Lower eyelid ectropion | Present | Absent | Absent |
| Drooping mouth corner and nasolabial fold disappearance | Present | Absent | Absent |
| Difficulty opening eyelids | ± | − | ++ |
Findings when facial nerve palsy is present
Section titled “Findings when facial nerve palsy is present”
Wikimedia Commons. File:Bellspalsy.JPG. Author: James Heilman, MD. License: CC BY-SA 3.0. Source ID: commons:File:Bellspalsy.JPG (2008).
左顔面神経麻痺（Bell麻痺）により左側前頭筋が麻痺し、左眉毛が眼窩上縁より下方へ下垂した麻痺性眉毛下垂の臨床像。右側に保たれた前額の横皺が左側では消失し、代償性前頭筋収縮の喪失を反映している。本文「顔面神経麻痺合併時の所見」の項で扱う眉毛下垂・前額皺消失・下眼瞼外反の合併所見に対応する。
顔面神経麻痺では眉毛下垂・口角下垂・鼻唇溝消失が併発する。左顔面神経麻痺では左前頭筋の麻痺によって眉毛下垂がみられ、上眼瞼皮膚弛緩が顕著となる。左下眼瞼も眼輪筋の弛緩性低下によって外反する。眼輪筋の収縮が減弱し、下眼瞼の下垂（三白眼）および外反を合併する。
眼瞼けいれん合併時の所見
Section titled “眼瞼けいれん合併時の所見”眼瞼けいれんの長期経過では、けいれんと開瞼努力の拮抗により周囲組織の弛緩（眉毛下垂・眼瞼下垂・皮膚弛緩など）が併発し、開瞼不能による機能的な失明に至ることがある。
Q
眉毛下垂と眼瞼下垂の違いは何ですか？
A
眉毛下垂は眉毛自体が正常位置（眼窩上縁付近）から下がった状態である。眼瞼下垂は上眼瞼縁が瞳孔にかかる状態（MRD-1低下）である。眉毛下垂が高度になると上眼瞼の余剰皮膚が増加し、あたかも眼瞼下垂のように見える「偽眼瞼下垂」を生じる。両者は併存することも多く、治療計画には両方の評価が必要である。
3. Causes and Risk Factors
Section titled “3. Causes and Risk Factors”3-1. Paralytic Brow Ptosis
Section titled “3-1. Paralytic Brow Ptosis”When the frontalis muscle is paralyzed due to facial nerve palsy (Bell’s palsy, Ramsay Hunt syndrome, stroke, trauma, tumor, etc.), the ability to elevate the eyebrow is lost, resulting in brow ptosis. Bell’s palsy typically presents as a peripheral complete paralysis, affecting the ipsilateral frontalis, orbicularis oculi, and orbicularis oris muscles. In central facial nerve palsy, the frontalis muscle is spared because it is innervated by both cerebral hemispheres, which is a distinguishing feature from peripheral palsy.
Paralytic brow ptosis is frequently accompanied by lagophthalmos (incomplete eyelid closure) due to orbicularis oculi paralysis, requiring comprehensive management from the perspective of corneal protection.
3-2. Age-Related (Involutional) Brow Ptosis
Section titled “3-2. Age-Related (Involutional) Brow Ptosis”Relaxation of the frontalis muscle and gravitational descent of the skin and subcutaneous tissue progress with aging. When blepharoptosis coexists, compensatory contraction of the frontalis muscle persists (resulting in prominent forehead wrinkles), and prolonged compensatory elevation leads to muscle fatigue, eventually causing decompensation and manifesting brow ptosis. Epidemiological prevalence data are scarce, but age-related brow ptosis is considered the most common type.
3-3. Symptomatic brow ptosis
Section titled “3-3. Symptomatic brow ptosis”In the long-term course of blepharospasm (benign essential blepharospasm), chronic antagonism between hypertonicity of the eyelid-closing muscles (orbicularis oculi and corrugator supercilii) and efforts to open the eyelids leads to relaxation of the periorbital tissues and brow ptosis.
Risk factors
Section titled “Risk factors”- Aging
- History of facial nerve disorders (Bell palsy, Ramsay Hunt syndrome, stroke, trauma, tumor)
- Long-term course of blepharospasm
- Chronic compensatory eyebrow elevation due to ptosis
4. Diagnosis and Examination Methods
Section titled “4. Diagnosis and Examination Methods”4-1. Clinical Measurements
Section titled “4-1. Clinical Measurements”Measurement of eyebrow position: Measure the distance from the superior orbital rim to the eyebrow. Normally, the eyebrow is located near or above the superior orbital rim.
Measurement of MRD-1: Measure the distance from the corneal light reflex to the upper eyelid margin (normal 3.5–5.5 mm) to assess for concurrent ptosis and differential diagnosis.
Confirmation of compensatory eyebrow elevation: The examiner fixes the forehead manually to eliminate compensatory eyebrow elevation and evaluates the true MRD-1. If MRD-1 decreases after fixation, it indicates that the previous normal value was false due to compensatory elevation.
Evaluation of forehead wrinkles: As a functional assessment of the frontalis muscle, observe the presence and degree of forehead wrinkles at rest and during upward gaze. In paralytic cases, forehead wrinkles disappear.
4-2. Differential Diagnosis
Section titled “4-2. Differential Diagnosis”| Disease | Main Features | MRD-1 | Excess Skin |
|---|---|---|---|
| Ptosis | Mainly due to decreased levator function | Decreased (<3.5mm) | May be present |
| Dermatochalasis | Mainly due to excess skin | Normal (≥3.5mm) | Prominent |
| Pseudoptosis | Caused by brow ptosis | Appears normal | Present |
| Relative ptosis of the contralateral eyelid due to lid retraction | Hering’s law | Decreased on one side only | Usually absent |
Q
Why is it important to check for brow elevation in ptosis examination?
A
Patients with brow ptosis or dermatochalasis may excessively contract the frontalis muscle to elevate the brows and secure the visual field (compensatory brow elevation). In this state, MRD-1 may appear normal, so the examiner must fix the forehead with a hand to eliminate compensation and evaluate the true MRD-1.
5. Standard treatment
Section titled “5. Standard treatment”5-1. Treatment of underlying disease
Section titled “5-1. Treatment of underlying disease”Management of facial nerve palsy: Clinical practice guidelines for Bell’s palsy recommend oral steroids within 72 hours of onset (e.g., prednisolone 60 mg/day for 5 days, then taper) 1. For Ramsay Hunt syndrome, antiviral drugs (acyclovir, valacyclovir) are used in addition to steroids. Physical therapy (facial muscle re-education, massage) is used as an adjunct.
Management of blepharospasm: Botulinum toxin injection (Botox®: type A botulinum toxin) is administered to the orbicularis oculi and corrugator muscles. If symptoms respond, brow ptosis also improves. Repeated injections every 3–4 months are usually required.
5-2. Eyelid surgery (for concurrent ptosis and lagophthalmos)
Section titled “5-2. Eyelid surgery (for concurrent ptosis and lagophthalmos)”In facial nerve palsy, lagophthalmos (incomplete eyelid closure) occurs frequently, and surgery may be needed to protect the cornea.
- Gold plate lid loading: A gold plate is implanted in the upper eyelid to assist closure by gravity.
- Upper eyelid levator lengthening or fascia graft: Performed when levator function is reduced.
5-3. Direct surgery for brow ptosis
Section titled “5-3. Direct surgery for brow ptosis”| Procedure | Indications | Overview |
|---|---|---|
| Subbrow skin excision (brow-scar blepharoplasty) | Primarily brow ptosis; thick skin | Skin directly below the brow is excised to elevate the brow position. The scar below the brow is hidden by the brow. |
| Frontalis suspension | Cases with ptosis | Suspension using the frontalis muscle |
| Direct brow lift | Correction of brow position via local incision | Elevation by excising skin above the brow |
| Endoscopic forehead lift | Elevation of the entire forehead | Minimally invasive cosmetic surgery to elevate the entire forehead |
Subbrow skin resection is the most direct surgical procedure for brow ptosis. By excising the skin directly below the eyebrow, the brow position is physically elevated. When blepharoptosis is present, correction of brow ptosis alone is insufficient, and combination with levator surgery should be considered. Direct brow lift has been reported to provide functional and cosmetic improvement in cases of brow ptosis with visual field impairment 2, and a comparative study of five surgical techniques showed that each technique provides a certain degree of elevation 3. Patient satisfaction and quality of life after brow ptosis surgery correlate well with preoperative subjective functional impairment and visual field measurements 4. For endoscopic forehead lift, a meta-analysis reported long-term elevation of 3.25 mm medially, 3.86 mm centrally, and 4.35 mm laterally 5.
5-4. Conservative management
Section titled “5-4. Conservative management”- Observation if visual field impairment due to excess skin is mild
- Temporary skin elevation with taping (symptomatic therapy for elderly patients or those not eligible for surgery)
Caution in cases of facial nerve palsy
In brow ptosis due to facial nerve palsy, management of lagophthalmos (corneal protection) must also be planned simultaneously. When performing surgical procedures on the brow or upper eyelid, always assess the increase or decrease in corneal exposure risk.
Q
What type of surgery is used to treat brow ptosis?
A
A representative surgical technique is brow-scar blepharoplasty, which excises skin directly below the eyebrow to elevate the brow position. If ptosis is also present, frontalis suspension may be selected. Both procedures are performed after prioritizing treatment of the underlying disease.
6. Pathophysiology and Detailed Mechanism of Onset
Section titled “6. Pathophysiology and Detailed Mechanism of Onset”Anatomical Basis
Section titled “Anatomical Basis”The eyebrows are elevated by the frontalis muscle (innervated by the temporal branch of the facial nerve). Antagonistic muscles include the corrugator supercilii and orbicularis oculi (innervated by the zygomatic and temporal branches of the facial nerve). Contraction of the frontalis muscle lifts the forehead skin and elevates the eyebrows. Loss of frontalis muscle function leads to brow ptosis due to inability to counteract gravity. Anatomical studies have shown that the lateral brow has poor deep supporting structures, making it prone to age-related lateral ptosis 6.
Paralytic Mechanism
Section titled “Paralytic Mechanism”The temporal branch of the facial nerve (cranial nerve VII) innervates the frontalis muscle. In peripheral facial nerve palsy (Bell’s palsy, Ramsay Hunt syndrome, trauma, tumor), denervation of the frontalis muscle leads to muscle atrophy and complete loss of brow elevation. In central facial nerve palsy, because the frontalis muscle is innervated by both cerebral hemispheres, it is spared even in unilateral central palsy (unilateral cortical lesions do not cause forehead paralysis).
If pathological synkinesis remains during the recovery process from paralysis, the frontalis muscle may remain incompletely recovered.
Age-related mechanisms
Section titled “Age-related mechanisms”With aging, relaxation of the frontalis muscle, skin, and subcutaneous tissue progresses, and the eyebrows descend due to gravity. When ptosis coexists, compensatory contraction of the frontalis muscle becomes chronic, deepening forehead wrinkles. Long-term compensatory contraction leads to frontalis muscle fatigue, and eventually the compensatory mechanism fails, resulting in overt brow ptosis.
Mechanisms due to blepharospasm
Section titled “Mechanisms due to blepharospasm”In benign essential blepharospasm, hypertonicity of the eyelid-closing muscles (orbicularis oculi and corrugator supercilii) persists. Chronic antagonism with eyelid-opening efforts causes mechanical relaxation of surrounding tissues (eyebrows, eyelids, skin). Brow ptosis, eyelid ptosis, and skin laxity occur concomitantly, and may eventually lead to functional blindness due to inability to open the eyelids.
7. Prognosis and course
Section titled “7. Prognosis and course”Bell’s palsy
Section titled “Bell’s palsy”Spontaneous complete recovery occurs in 70–85% of cases. Recovery is usually observed within 3–6 months, and brow ptosis improves or resolves along with improvement in frontalis muscle function. Early steroid treatment improves prognosis. If pathological synkinesis persists, recovery of the frontalis muscle may remain incomplete.
Ramsay Hunt syndrome
Section titled “Ramsay Hunt syndrome”Recovery rate is lower than in Bell’s palsy. In prolonged cases, surgical intervention (e.g., subbrow skin excision, frontalis muscle suspension) may be considered.
Age-related brow ptosis
Section titled “Age-related brow ptosis”This is essentially an age-related change and does not resolve spontaneously. Surgery (subbrow skin excision, direct brow lift, endoscopic forehead lift) can provide good cosmetic and functional improvement. With progression of aging changes, skin laxity may recur.
Blepharospasm
Section titled “Blepharospasm”Symptoms are controlled by repeated administration of botulinum toxin every 3 to 4 months. Over the long term, relaxation of surrounding tissues may progress, and if brow ptosis or eyelid ptosis worsens, surgical evaluation is performed.
Q
Can brow ptosis due to facial nerve palsy be cured?
A
In Bell’s palsy, 70-85% recover spontaneously, and brow ptosis improves along with recovery of frontalis muscle function. Recovery is usually observed within 3 to 6 months. If recovery is insufficient, surgical intervention (e.g., subbrow skin excision, frontalis sling) is considered.
8. References
Section titled “8. References”
眼瞼下垂
腱膜性・先天性など原因別の眼瞼下垂を解説。眉毛下垂との鑑別・代償性眉毛挙上の評価についても記述。
眼瞼皮膚弛緩症
加齢性の眼瞼余剰皮膚。MRD-1による評価と眉毛下皮膚切除術の術式選択を解説。
Footnotes
Section titled “Footnotes”-
Baugh RF, Basura GJ, Ishii LE, et al. Clinical practice guideline: Bell’s palsy. Otolaryngol Head Neck Surg. 2013;149(3 Suppl):S1-S27. PMID: 24189771 ↩
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Har-Shai Y, Gil T, Metanes I, Scheflan M. Brow lift for the correction of visual field impairment. Aesthet Surg J. 2008;28(5):512-517. PMID: 19083571 ↩
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Georgescu D, Anderson RL, McCann JD. Brow ptosis correction: a comparison of five techniques. Facial Plast Surg. 2010;26(3):186-192. PMID: 20524166 ↩
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Mellington F, Khooshabeh R. Brow ptosis: are we measuring the right thing? The impact of surgery and the correlation of objective and subjective measures with postoperative improvement in quality-of-life. Eye (Lond). 2012;26(7):997-1003. PMID: 22595909 ↩
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Şibar S, Uğraş Dikmen A, Erdal AI. Long-term Stability in Endoscopic Brow Lift: A Systematic Review and Meta-Analysis of the Literature. Aesthet Surg J. 2025;45(3):232-244. PMID: 39542644 ↩
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Knize DM. An anatomically based study of the mechanism of eyebrow ptosis. Plast Reconstr Surg. 1996;97(7):1321-1333. PMID: 8643714 ↩