Third Eyelid Protrusion

Basics

Definition

Abnormal protrusion (elevation) of the third eyelid.

Pathophysiology

Dogs-movement of the third eyelid is passive.
Cats-partial sympathetic nervous control of the third eyelid.
Elevated third eyelid results from a space-occupying mass in the orbit pushing the third eyelid forward, enophthalmos, sympathetic denervation, or a painful eye.

Systems Affected

Nervous-autonomic nervous system
Ophthalmic-third eyelid(s); orbit; globe

Signalment

See “Causes”

Signs

May have none.
May be associated with primary condition-exophthalmos; enophthalmos; blepharospasm; Horner's syndrome.
Unilateral or bilateral-depending on cause.

Causes

Unilateral

Blepharospasm

Painful ocular condition-corneal ulcer; glaucoma; uveitis; or ocular foreign body.
May cause the globe to be retracted and secondary third eyelid elevation.

Space-Occupying Orbital Mass

Often an abscess or neoplasm.
May displace the third eyelid anteriorly.
Usually causes exophthalmos.
Abscess-generally seen in young patients; usually acute onset; painful on palpation.
Neoplasm-usually seen in old patients; gradual onset; frequently not painful (see Orbital Diseases [Exophthalmos, Enophthalmos, Strabismus]).

Enophthalmos

Globe-recedes into the orbit, causing third eyelid to appear elevated.
Unilateral-may be caused by trauma, orbital fat atrophy, and inflammation; may be secondary to orbital neoplasia in cats (see Orbital Diseases).

Microphthalmus or Phthisis Bulbi

Small globes-cause the third eyelid to appear elevated.
Microphthalmus-congenital; may be idiopathic; inherited in specific breeds (collie eye anomaly); may result from toxin ingestion (griseofulvin in pregnant cats).
Phthisis bulbi-occurs with severe damage to the globe (severe uveitis, glaucoma, or trauma); ciliary body fails to produce aqueous humor; diminished; small, fibrotic globe from chronic inflammation.

Other

Horner's syndrome-clinical signs develop after sympathetic denervation; elevated third eyelid; enophthalmos; ptosis (drooping upper eyelid); miosis (see Horner's Syndrome).
Neoplasia of the third eyelid-most common: adenocarcinoma of the gland of the third eyelid and squamous cell carcinoma of eyelid.
Cherry eye-see Prolapsed Gland of the Third Eyelid (Cherry Eye).
Everted or scrolled cartilage of the third eyelid-seen in Wiemaraners, Great Danes, German shorthaired pointers, and other breeds; the T-shaped cartilage of the third eyelid is rolled away from the surface of the eye instead of conforming to the corneal surface.
Symblepharon-post-inflammatory adhesions between the third eyelid and cornea or conjunctiva. Common in cats who had ocular surface inflammation before the eyelids opened.

Bilateral

Exophthalmos

Space-occupying lesions of both orbits.
Usually caused by inflammatory lesions (e.g., eosinophilic myositis and extraocular muscle polymyositis).

Conformational

Breed-specific-Doberman pinschers and pointers.
Deep orbits and prominent third eyelids.
Not pathologic.
No treatment needed.

Plasmoma

Immune-mediated thickening and hyperemia of the leading edge of the third eyelid.
Seen almost exclusively in German shepherds.
May be associated with chronic superficial keratitis (pannus).

Other

Blepharospasm.
Enophthalmos-caused by dehydration, bilateral orbital fat atrophy secondary to severe cachexia, and chronic masticatory muscle myositis.
Haw syndrome (cats)-idiopathic bilateral elevation of the third eyelids; all other aspects of the ophthalmic examination are normal; usually resolves in 3–4 weeks without treatment.
Dysautonomia (Key-Gaskell syndrome)-bilateral elevated third eyelids; dilated non-responsive pupils; KCS; dry mucosal surfaces; anorexia; lethargy; regurgitation; megaesophagus; bradycardia; megacolon; distended bladder (see Dysautonomia).
Tranquilizers-many (e.g., acepromazine) cause bilateral third eyelid elevation.
Fatigue-may cause transient third eyelid elevation, especially in dogs prone to ectropion.

Risk Factors

Depends on cause

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

Most common causes of acute onset of unilateral condition-ocular pain (e.g., corneal ulcer and uveitis); orbital inflammation (e.g., orbital abscess and cellulitis).
Middle-aged or older patient with unilateral, non-painful condition-third eyelid or orbital neoplasm likely.
All patients-must rule out a small eye (microphthalmus or phthisis bulbi) and Horner's syndrome.
Likely causes of bilateral condition-systemic illness (e.g., dehydration, cachexia, and dysautonomia); associated with conformational abnormalities.
Prolapsed gland of the third eyelid-medial aspect of the third eyelid swollen; the third eyelid itself usually normal.

CBC/Biochemistry/Urinalysis

Leukocytosis and a left shift-with orbital inflammatory processes.
Blood work-generally unrewarding in differentiating causes.

Other Laboratory Tests

Dysautonomia-confirmed by measuring urine and plasma catecholamine concentrations and pharmacologic testing of the autonomic nervous system.

Imaging

Thoracic radiography-all patients with Horner's syndrome to rule out intrathoracic cause of sympathetic denervation; patients with suspected neoplasia to evaluate for metastatic disease.
Orbital ultrasound-recommended to help localize suspected orbital mass and define its nature (e.g., solid or cystic).
CT or MRI-further define suspected or known orbital mass.
Skull radiographs-rarely show signs of orbital disease unless the lesion is very large and destructive.

Diagnostic Procedures

Thorough ophthalmic examination.
Slit-lamp biomicroscope or some other source of magnification-recommended to localize any potential ocular abnormality.
All patients with unilateral condition-examine both surfaces of the third eyelid and the conjunctival cul-de-sac carefully for a foreign body or symblepharon.
Pharmacologic testing-localize lesion(s) with Horner's syndrome (see Horner's Syndrome).
Exploratory surgery and biopsy-may be only means to make a definitive diagnosis for a suspected orbital or third eyelid mass.

Cytology

For suspected mass lesions-orbital mass or mass of the third eyelid; fine-needle aspirate; may help make the diagnosis.
Unguided fine-needle aspiration-attempt only if the mass is anterior to the equator of the eye.
Ultrasonography-guided fine-needle aspiration-for masses posterior to the eye; help avoid delicate retrobulbar structures.
Third eyelid scrapings (German shepherds with suspected plasmoma)-reveal plasma cells and lymphocytes.

Treatment ⬆ ⬇

Treatment

Depends on cause.
Painful condition-remove the cause of the irritation (e.g., foreign body); treat the primary ocular condition.
Orbital cellulitis and abscess-generally respond well to drainage and systemically administered antibiotics.
Orbital neoplasms-usually require wide surgical excision via an orbital exenteration; may require adjunct therapeutic modalities (e.g., radiotherapy or chemotherapy) if excision is incomplete.
Microphthalmic eyes-usually none required; remove the globes if painful or subject to recurrent conjunctivitis.
Blind traumatized eyes-enucleate to prevent formation of intraocular sarcomas (cats).
Horner's syndrome-treat cause, if known (∼50% of dogs and cats); otherwise will usually resolve without treatment in 4–12 weeks.
Surgical removal of the entire third eyelid-indicated for third eyelid neoplasia; may require adjunct therapeutic modalities (e.g., radiotherapy or chemotherapy) if the surgical margins are not free of neoplasm.
Radiotherapy around the eye-may result in severe keratitis, dry eye, and cataracts; discuss enucleation with the client before initiating treatment if eye will be in the field.
Orbital exenteration-may be warranted if the mass extends into the orbit.
Plasmomas-usually controlled with topically applied medications; not cured; inform client that some form of treatment will likely be needed for the life of the patient; topical corticosteroids (0.1% dexamethasone or 1% prednisolone acetate; q6h initially, reduced to q24h when the lesion appears resolved); topical 1% cyclosporine in oil (q12h) also effective.
Haw syndrome-usually resolves in 3–4 weeks without treatment.
See Dysautonomia.

Medications ⬆ ⬇

Medications

Drug(s) Of Choice

See “Treatment”

Contraindications

Topical corticosteroids-never use with a corneal ulcer.

Precautions

N/A

Possible Interactions

N/A

Alternative Drug(s)

N/A

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring

Malignant neoplasm-take thoracic radiographs every 3–6 months to monitor for metastatic disease.

Possible Complications

Neoplasm-extension to or infection of adjacent orbital structures (e.g., eye, orbit, orbital sinuses, and cranial cavity) possible; metastasis to distant sites (usually thorax or liver) possible (approximately 90% are malignant).
Vision loss-from the lesion itself; from the elevation; from treatment (e.g., radiotherapy and exenteration).

Miscellaneous ⬆

Miscellaneous

Associated Conditions

N/A

Age-Related Factors

Middle-aged to older patients-at risk for neoplastic diseases of the third eyelid and orbit.
Young patients-at risk for congenital abnormalities; affected by inflammatory conditions of the third eyelid more frequently than are old animals.

Zoonotic Potential

N/A

Pregnancy/Fertility/Breeding

N/A

Synonyms

Elevated third eyelid
Haw syndrome (cats)

See Also

Abbreviations

CT = computed tomography
KCS = keratoconjunctivitis sicca
MRI = magnetic resonance imaging

Suggested Reading

Hendrix DVH. Diseases and Surgery of the Canine Conjunctiva and Nictitating Membrane. In: Gelatt KN, Gilger BC, Kern T, eds., Veterinary Ophthalmology, 5th ed. Ames, IA: Wiley-Blackwell, 2013, pp. 945–975.

Sharp NH, Nash AS, Griffiths IR. Feline dysautonomia (the Key-Gaskell syndrome): A clinical and pathological study of forty cases. J Small Anim Pract 1985, 25:599–615.

Author Brian C. Gilger

Consulting Editor Paul E. Miller

section name header

Basics ⬇

Diagnosis ⬆ ⬇

Treatment ⬆ ⬇

Medications ⬆ ⬇

Follow-Up ⬆ ⬇

Miscellaneous ⬆