Lesson 126 - Diseases and Disorders of the Eyelids

What are the functions of the eyelid?

1. protect globe

2. clean and lubricate

3. contribute to and distribute tear film, move fluid into nasolacrimal duct

4. Remove debris and foreign bodies

What are the components of the eyelid?

1. Skin

2. Orbicularis oculi muscle

3. Tarsal plate/glands

4. Conjunctiva

What glands are located in the eyelid?

meibomian glands (aka tarsal glands)

What do meibomian glands contribute to the tear film?

lipids

Why are lipids essential in tears?

prevents premature evaporation

What are the muscles of the eyelids?

1. Orbicularis oculi

2. Levator palpebrae superioris

3. Muller's muscle

4. Retractor anguli oculi

What is the function and innervation of the orbicularis oculi?

1. Closes palpebral fissure

2. Facial nerve (CN 7)

What is the function and innervation of the levator palpebrae superioris?

1. Raises upper lid

2. Oculomotor nerve (CN3)

What is the function and innervation of muller's muscle?

1. Raises upper lid

2. Sympathetic innervation

What is the function of the retractor anguli oculi?

supports and keeps lateral canthus extended

semilunar fold of conjunctiva surrounding a T-shaped cartilaginous support

What is the third eyelid?

What structure is located at the base of the third eyelid cartilage?

a gland

What are the protective functions of the third eyelid?

1. produces and distributes tears

2. removes debris

3. acts as a physical barrier

What additional function does the third eyelid serve beyond protection?

immune surveillance

How does third eyelid movement differ in cats?

more robust voluntary movement

What should be assessed when looking at the third eyelid?

1. Symmetry

2. Margin position, integrity

3. Swelling

4. Wounds, ulcerations

5. Condition of glands

6. Position of lashes

7. Effectiveness of blink mechanism

8. Potential consequences for globe

What are the general diseases and disorders of the eyelid?

1. Congenital anomalies and neonatal disorders

2. Inflammation (Blepharitis)

3. Trauma

4. Anatomical problems with lid position

5. Neoplasia

6. Facial nerve paresis/paralysis

7. Lash disorders

What are the congenital diseases and disorders of the eyelid?

1. Neonatal ophthalmia

2. Eyelid agenesis

What are some examples of trauma to the eyelid?

1. Lacerations

2. Blepharoedema

What are some anatomical problems with lid position?

1. Entropion

2. Ectropion

3. Macroblepharon

4. Lateral canthal instability

What are some lash disorders?

1. Distichiasis

2. Ectopic cilia

What is ankyloblepharon in puppies and kittens?

physiologic fusion of the eyelids until 10-14 days of age

When does ankyloblepharon become abnormal?

when it persists beyond 10-14 days of age

In what type of neonates is ankyloblepharon not present?

precocious neonates

Where does infection occur in neonatal ophthalmia?

beneath fused eyelids

What is the main risk if neonatal ophthalmia is not treated promptly?

irreversible, potentially blinding scarring

What is the correct initial management of neonatal ophthalmia?

prematurely open the lids and treat the infection

How should the eyelids be opened in neonatal ophthalmia?

manually separate the upper and lower lids (do not cut them)

What treatments should be applied after opening the lids?

flush the fornix and apply topical antibiotics and lubricants

Why are lubricants important in neonatal ophthalmia?

lid function is immature and tear production is low

What is eyelid agenesis?

absence of a portion of the eyelid

What is a common consequence of eyelid agenesis?

exposure keratitis

What ocular abnormalities may be associated with eyelid agenesis?

1. cataract

2. retinal dysplasia

3. posterior segment colobomas

4. KCS

What are the treatment options for eyelid agenesis?

1. Lubricants

2. Surgical correction if severe

3. Various techniques seek to improve corneal protection, decrease globe exposure, correct trichiasis

What is a surgical correction of eyelid agenesis?

lip-to-lid procedure

What is blepharitis?

inflammation of the eyelid skin or glands

What are the common clinical signs of blepharitis?

1. swelling

2. erythema

3. chemosis

4. ulcerations

5. excoriations

6. discharge

What areas should be examined when evaluating blepharitis?

outside and inside of the eyelid, including skin, palpebral conjunctiva, and meibomian openings

What are the causes of blepharitis?

1. trauma (external or self-inflicted)

2. infection often secondary, parasites, Staphylococcus spp

3. allergy (environmental or drug reaction)

4. immune-mediated causes

What is the first step in evaluating blepharitis?

rule out infection

What tests are used to rule out infection in blepharitis?

skin scrapings, cytology, and culture and susceptibility

When might a deep biopsy be required in blepharitis cases?

histopathology and culture

What should be considered if no infectious cause is identified in blepharitis?

allergy or other immune-mediated conditions

What additional factors should be evaluated when considering non-infectious causes of blepharitis?

history and presence of lesions elsewhere

What is meibomianitis?

swelling of meibomian glands or ductal openings

How is meibomianitis treated?

tetracycline antibiotics and corticosteroids

What is puppy strangles?

immune-mediated reaction to normal Staphylococcal flora

How is puppy strangles treated?

systemic antibiotics and corticosteroids

What are important history questions for blepharitis?

1. Signalment

2. Duration

3. Seasonality

4. Other lesions

4. Diet, meds, travel, all the things

What samples should be taken with blepharitis?

1. Cytology

2. Skin Scrapings

3. Culture and Susceptibility

4. Histopathology

What does drug reaction blepharitis frequently occur with?

depigmentation

What topical ophthalmic medications cause drug reaction blepharitis?

1. Preservatives

2. Neomycin

3. Dorzolamide

What is the result of blunt eyelid trauma and how is it treated?

1. Blepharoedema

2. Supportive care and anti-inflammatories

What is the result of sharp eyelid trauma and how is it treated?

1. Lacerations

2. Surgical repair

How are eyelid lacerations treated?

1. Need to be repaired ASAP

2. Minimal debridement

3. Two layer closure if extensive

4. First align lid margin and close with a figure-of-eight suture

What is the normal corneal diameter?

14-18 mm

What is the normal length of the palpebral fissure?

23-25 mm

What is entropion?

inversion of eyelid margins

What are the two types of entropion?

anatomic and spastic

What causes anatomic entropion?

1. Breed predispositions

2. Asymetric growth/hormonal influence (tom cats)

3. Aging/loss of orbital fat (old cats)

What causes spastic entropion?

pain

What is the treatment for entropion?

surgical but depends upon extent and animal's age

When should a permanent surgical correction for entropion never be performed?

any animal <6 months of age

What should be done before entropion surgery?

1. Treat pre-existing problems (pyoderma)

2. Evaluate extent while animal is awake

3. Apply topical anesthetic to differentiate between spastic and anatomic

What is an important consideration with entropion surgery?

slightly under-correct

When is temporary tacking a good solution for entropion?

puppies or suspected spastic entropion

How is temporary tacking performed?

vertical mattress sutures with non-absorbable sutures or staples

What determines the choice of surgical procedure for entropion?

underlying problem

What are common underlying issues considered when selecting entropion surgery?

lids too long and/or unstable lateral canthus

What is the most common surgical technique used for entropion and how can it be modified?

Hotz-Celsus procedure; can be combined with wedge resection or lateral canthal closure

What are other surgical procedures used to correct entropion?

1. Medial canthal triangle method

2. arrowhead procedure

3. Wyman's lateral canthoplasty

4. Stades upper lid procedure

What is another term for macroblepharon?

euryblepharon

What is macroblepharon?

large palpebral fissure relative to globe size and excessive lid length

What condition is macroblepheron a part of?

brachycephalic complex

What can macroblepheron lead to?

proptosis

What are common complications of macroblepharon?

keratitis and tear quality deficiencies

How can we combat the complications of macroblepharon?

lubrication

What can patients with macroblepheron benefit from?

eyelid shortening procedure

What are the eyelid shortening procedures?

1. Medial canthoplasty

2. Partial permanent tarsorrhaphy

In what type of patients is medial canthoplasty commonly performed?

small breed dogs

What conditions does medial canthoplasty correct?

1. Medial trichiasis

2. Entropion

3. Euryblepharon

What is the main structural effect of medial canthoplasty?

shortens the palpebral fissure

What additional benefit can medial canthoplasty provide?

may help prevent proptosis

How is medial canthoplasty closed?

two-layer closure

How is the deep layer closed in medial canthoplasty?

close dead space using 6-0 Vicryl in a simple continuous pattern

How is the skin closed in medial canthoplasty?

figure-of-eight at the margin and simple interrupted sutures using 5-0 nylon or silk

What is ectropion?

eversion of eyelid margin

What breeds are predisposed to ectropion?

Basset Hounds, Saint Bernards, Bloodhounds, many Spaniel breeds

What are other causes of ectropion besides breed-related?

cicatricial and senility

When is surgical treatment indicated for ectropion?

when keratitis or conjunctivitis are present

How does eyelid neoplasia typically differ between dogs and cats?

usually benign in dogs and usually malignant in cats

What is a common effect of eyelid neoplasia on the eye?

irritation to the globe

What are common types of eyelid tumors in dogs?

meibomian adenomas, epitheliomas, papillomas, and melanomas

What are common types of eyelid tumors in cats?

squamous cell carcinoma, basal cell carcinoma, fibrosarcoma, and mast cell tumor

What surgical technique is used when less than 1/3-1/4 of the eyelid margin is involved with neoplasia?

"V" or four-sided ("house") excision

What surgical approach is used for larger eyelid defects after tumor removal?

sliding skin grafts (H-plasty) or other reconstructive procedures

When is two-layer closure used in eyelid tumor surgery?

for all but the smallest defects

How is the deep layer closed in eyelid reconstruction?

small gauge (6-0) absorbable suture using simple continuous or mattress pattern, with no sutures exposed through the palpebral conjunctiva

How is the skin closed in eyelid reconstruction?

small gauge (5-0) non-absorbable suture, with figure-of-eight at the margin followed by simple interrupted sutures

What is the purpose of cryotherapy in eyelid neoplasia?

debulk the mass without complete excision