Unit 1 - Eyelids Flashcards
What are the three main layers of the eyelid?
Outer layer, middle layer, and innermost layer
What are the components of the outer layer of the eyelid?
Skin, hair follicles, and sebacious glands
T/F: Dogs and cats have both upper and lower lid cilia.
False - they only have upper lid cilia
What are the components of the middle layer of the eyelid?
Muscle, tarsal plate, and meibomian glands
What are the components of the innermost layer of the eyelid?
Palpebral conjunctiva
What are the functions of the eyelid?
Corneal protection
Production, distribution, and drainage of tear film
What does the orbicularis oculi muscle do and what innervates it?
It closes the eye lids and is innervated with the facial nerve (CN VII)
What does the levator palpebra superioris muscle do and what innervates it?
It opens the eyelid and is innervated by the oculomotor (CN III)
What does the Muller’s muscle do and what innervates it?
It elevates the upper lid and is innervated by the sympathetic nervous system
What provides sensation to the eyelid?
The ophthalmic and maxillary branches of the trigeminal nerve (CN V)
In what direction should eyelids close?
From lateral to medial
What is ankyloblepharon?
Adhesion of the eyelid margins
When is ankyloblepharon normal?
Until 10-14 days postpartum in dogs and cats
When is ankyloblepharon abnormal?
If it persists past 15 days of age
Can occur with ophthalmia neonatorum
How should ankloblepharon be medically managed if it has been 15+ days post partum?
They should be opened with gentle traction on the eyelids or by blunt dissection
What is eyelid agenesis?
When there is absence of a portion of the eyelid
What lesion can eyelid agenesis result in?
Secondary trichiasis and exposure keratitis due to the cornea being exposed
What species is eyelid agenesis most common in?
Cats, especially feral, and horses
If the eyelid agenesis defect is small, how should it be treated?
Frequent use of ocular lubricants, cryosurgery for trichiasis hairs, and a simple wedge resection
If the eyelid agenesis defect is large, how should it be treated?
Reconstructive procedure to form a functional eyelid - refer to a specialist
What is a micropalpebral fissure?
A congenital small eye opening that may accompany other congenital defects (microphthalmos)
What breeds typically get micropalpebral fissures?
Miniature breeds, sheltie, collie, chow chow, Kerry Blue terrier, and others
How is micropalpebral fissure treated?
It rarely requires surgical intervention, but lateral augmentation canthoplasty if entropion is present and problematic
What is macropalpebral fissure?
Overly large eyelid openings
Macropalpebral fissure in combination with a shallow orbit results in what?
Conformational exophthalmos
What breeds is macropalpebral fissure common in?
Brachycephalic breeds
What other ocular manifestions can result from macropalpebral fissure?
Increased proptosis risk, possible lagophthalmos, exposure keratitis, and concurrent trichiasis
How is macropalpebral fissure treated and when is it indicated?
Surgical shortening of the eyelids is indicated if pigmentation, exposure keratits, or recurrent corneal ulcers
What surgical treatment for marcopalpebral fissures addresses multiple issues that brahcycephalics have with their eyes?
medial canthoplasty
What is entropion?
Inversion of the eyelid margin
What is ectropion?
Eversion of the eyelid margin
What is diamond eye?
A combination of entropion and ectropion
Common in Bloodhounds, Clumber Spaniel, St. Bernard, and Great Dane
What are the clinical signs associated with entropion?
Pain and squinting (blepharospasm) and excessive lacrimation (epiphora)
What corneal sequelae result from entropion?
Ulceration, vascularization, pigmentation, and corneal scarring
What is anatomic entropion?
Entropion in young dogs that is breed-related
What is spastic entropion?
Lid spasm associated with pain
What is cicatrical entropion?
Entropion resulting from previous surgery, trauma, or chronic eyelid inflammation
How is entropion temporarily corrected?
Eyelid tacking
When is temporary entropion treatment indicated?
In cases of anatomic entropion and spastic entropion
How is entropion permanently corrected?
Hotz-Celsus (or Others)
When is permanent correction of entropion indicated?
Anatomic entropion in mature animals or cicatrical entropion
How is temporary entropion correction done?
Place nonabsorbable vertical mattress sutures or skin staples on the lower eyelid to pull it out of the eye. Leave in for 3-4 weeks or longer
Describe the Hotz-Celsus procedure.
Incise 2 mm from, while arcing parallel to, the eyelid margin.
Make a second incision at maximal entropion degree and arc it to connect both ends
Remove adequate subcutaneous tissues (test that cut margins can passively stay together)
Close with 5-0 suture; simple interrupted.
What should be done to determine how much skin to remove?
Assess the eyelid conformation with minimal restraint in a conscious, unsedated animal
Apply topical anesthetic to relieve a spastic component
Delay permanent correction until the animal is skeletally mature
What should you NOT do when determining how much skin to remove?
Do not over correct - you could end up causing iatrogenic ectropion
What are the rough guidelines for excision width in permanent entropion treatment?
Mild: 4-5 mm
Moderate: 6-7 mm
Severe: 8-9
When is ectropion typically corrected?
If there is associated problem conjunctivitis or corneal disease
What is the conservative treatment for ectropion?
Eyewash rinsing +/- gel lubricant
What surgeries can be done to treat ectropion?
Wedge resection, V to Y plasty, or blepharoplasty
Where are V or Y plasties centered?
on the ectropic area
What is trichiasis?
Normal facial hairs that contact the cornea/conjunctiva.
What is distichiasis?
Hairs that emerge from meibomian gland openings
What is ectopic cilia?
Hairs that emerge through the palpebral conjunctiva
When does trichiasis cause a problem?
In combination with entropion
Bristly nasal fold trichiasis
When combined with KCS
When combined with functional NLD obstruction
How is nasal fold trichiasis treated?
Nasal fold excision or medial canthoplasty if irritation or ulceration
How is medial canthus trichiasis or hairy caruncle treated?
Medial canphoplasty or cryotherapy if irritating or tear wicking
In cases of entropion trichiasis, how can it be treated?
entropion correction
What is a good way to ID distichiasis?
Look for a mucus glob on the eyelid margin
What are the ways to treat distichiasis?
Benign neglect, epilation, electrolysis, cryosurgery, thermal cautery, and laser excision (ill advised)
Epilation is a _______ fix. It helps to establish the significance of distichia.
temporary
Cryosurgery for distichiasis uses _______ or ____ to destroy the follicles but can cause __________ and ________.
Nitrous oxide or liquid nitrogen
temporary eyelid depigmentation and swelling
What is the preferred treatment for distichiasis?
thermal cautery
What is the typical signalment for ectopic cilia?
They are typically a young patient with a nonhealing or recurrent superficial corneal ulcer - most common dorsally
How is ectopic cilia treated?
Remove the follicle completely and treat area with cryotherapy or thermal electroccautery
What is hordeolum (stye)?
Infection of the eyelid glands
What is chalazion?
Granuloma formation from inspissated meibomian gland secretions
How is hordeolum and chalazion treated?
Hot compresses, manual expression of lesions, surgical incision and curettage, and/or topical and systemic antibiotics
What is blepharitis?
Inflammation of the eyelids
What is the general workup protocol for blepharitis?
Derm database - impression, skin scraping, hair pluck, cytology +/- culture, biopsy and histopath
What is the clinical presentation for juvenile cellulitis?
Usually young of age, acute pyoderma of the head, bilateral eyelid involvement, and pyogranulomatous dermatitis with furunculosis and panniculitis
How is juvenile cellulitis treated?
Systemic corticosteroids +/- systemic antibiotic if bacteria on cytology
What is the signalment for bacterial blepharitis?
adult dogs
What bacterial agents typically cause bacterial blepharitis?
Staphylococcus and Streptococcus
How is blepharitis treated?
Treat the underlying cause if known
Cleanse eyelid with dilute baby shampoo
____% of canine eyelid tumors are benign.
75%
What are the most common eyelid neoplasms in dogs in order from most to least?
Meibomian gland adenoma»> melanocytoma> papilloma
T/F: Most feline eyelid neoplasias are malignant.
True
What are the most common eyelid neoplasms in cats in order from most to least?
SCC > mast cell > hemangiosarcoma
What are the most common eyelid neoplasms in horses in order from most to least?
SCC > sarcoid > melanoma
What are the most common eyelid neoplasms in cows?
SCC
What is the therapeutic goal for eyelid masses?
Destroy the tumor while preserving eyelid function and cosmesis
What are the treatment options for eyelid masses?
surgical resection, debulk and cryotherapy, CO2 laser, and benign neglect
Describe the procedure for a wedge or ‘house’ resection.
Make an excision that is 30% the width of the length of the eyelid.
From base to apex, make the height of the incision twice the excision width.
Perform a 2-layer closure with 5-0 vicryl
How do you perform the 2-layer closure for a wedge resection?
Place a few sutures buried in the deep layer if there is a large defect. For the skin and margin closure, make a figure-eight suture at the eyelid margin then interrupted skin sutures. Tie the suture ends into subsequent knots like a ‘ponytail’
Specifically how do you do a figure-eight suture?
Start skin through subcutaneous tissue (side A).
Subcutaneous through meibomian gland opening of the opposite side (side B).
Meibomian gland opening through subcutaneous of the opposite side (side A).
Subcutaneous through skin exit of the opposite side (side B).
For what type of eyelid tumor is debulking and cryosurgery recommended?
adenoma
How are eyelid adenomas debulked and cryo-ed (lol verbs are hard)?
Place the patient under general anesthesia or deep sedation
Place a chelazion clamp to stabilize the eyelid and provide hemostasis
Incise conjunctival surface and debulk
Freeze with two fast freeze/slow thaw cycles
Postoperatively, what will occur in a patient that just had debulking and cryosurgery?
Focal swelling and temporary depigmentation
For what eyelid tumor type is a CO2 laser indicated?
adenoma
How is a CO2 laser used to remove an adenoma?
Outline and excise the mass w/ laser while minimizing eyelid margin loss. Treat/ablate remaining tissue bed
When is an advanced eyelid tumor removal indicated?
If the tumor is malignant or too large for a wedge resection - refer
T/F - A complete ophthalmic exam is not necessary if there is eyelid trauma
False - need to look at the whole eye. Globe perforation is more important to manage
What is the medical therapy for blunt injury to the eyelid?
Systemic anti-inflammatory +/- topical for uveitis
What is the recommended surgical prep for penetrating injury to the eyelid?
Use betadine solution and saline prep.
When should repair for recent eyelid lacerations be done? Older injuries?
Recent injuries (<6 hours) ASAP Older injuries when severe swelling has subsided
How are eyelid lacerations repaired?
Minimal debridement. 2-layer closure with figure-eight margin suture.
Assure apposition of lid margin and that there are no sutures contacting the cornea
What can result if there is poor lid margin apposition when repairing eyelid lacerations?
Trichiasis, exposure keratitis, and scar tissue that can abrade the cornea
What is the postoperative management for eyelid lacerations?
Topical antibiotic, systemic antibiotic, systemic anti-inflammatory, pain control, cold compresses, and e-collar (prevent further trauma)
When should eyelid laceration repair be rechecked and sutures removed?
10-14 days
