Eyelid Diseases Flashcards
What is the normal function of the eyelid? What normal structures does it contain?
produces the lipid portion of tear film to keep it from evaporating
- lined by conjunctiva
- cilia
- glands: Meibomian (lipid secretions!), Zeis, Moll
What 2 roles do the cilia have?
- protection
- vibrissae - sensory
What nerve function is required for blinking reflex?What stimulates this reflex?
normal trigeminal (VII, ophthalmic) and facial nerve (VII) function
sensation of corneal dryness stimulates blinking to spread tears across the cornea and move them toward the nasolacrimal canaliculi
What nerve function is required for the palpebral reflex?
lateral mandibular and medial maxillary branch of the trigeminal (V) senses pressure on canthus
facial nerve (VII) innervates orbicularis oculi, which causes blinking
What is trichiasis? What are some etiologies?
pathologic condition in which hairs from normal skin reach and irritate the corneoconjunctival surface
- prominent nasal folds (Bulldogs, Pekingese)
- distichiasis
- entropion
- ectopic cilia
- ciliated caruncle
- eyelid agenesis
What is blepharospasm? What is the main cause?
involuntary tight closure or spasmodic blinking of the eyelid
anything that causes the eye to be painful
What is ankyloblepharon? How is it treated? What can it be confused with?
congenital anomaly causing the delayed or complete failure of the opening of the palpebral fissures
lids must be gently opened to avoid infection and accumulation of debris
ophthalmia neonatorum - purulent debris behind lid common in kittens with herpesvirus
What is eyelid agenesis? How is it treated?
absence of the lateral 1/3 to 2/3 of the upper eyelid more common in shelter/feral cats, leading to keratitis in the exposed portion of the eye
procedures that remove the trichiasis and create eyelid margins
What is macropalpebral fissure syndrome? In what dogs is this most common?
shallow orbit and prominent globes, causing the eyelids to not completely close and sclera to show
- Pugs
- Shih Tzus
- Pekingese
- brachycephalic breeds!
What clinical signs are most commonly seen with macropalpebral fissure syndrome?
- poor corneal sensitivity due to decreased/incomplete blinking —> exposure = corneal scarring, pigmentation, or vascular growth
- medial entropion/facial fold rubbing against eye causing keratitis or irritation
How is macropalpebral fissure syndrome treated? What breed has a specific genetic disposition?
scarring/pigmentation —> topical cyclosporine and lubrication to decrease irritation
PUGS - pigment on cornea
What are the 2 aspects of treating mild cases of macropalpebral fissure syndrome?
- artificial tears - lubrication to treat for qualitative dry eye disease
- cyclosporine, tacrolimus - tear production, corneal pigmentation
How are more severe cases of macropalpebral fissure syndrome treated?
medial canthoplasty - small amount of the medial upper and lower lid margin is removed and sutured together to close the eye down partially and allow for more complete blinking
+ protects from medial, ventral entropion and nasal fold trichiasis
What is entropion?
inversion of all or part of the eyelid margin, causing the outer skin to come into contact with the conjunctiva and/or cornea (trichiasis), which leads to keratitis, ulcers, or blepharospasm
What is the most common cause of hereditary entropion? What is the age of onset?
small eye, big orbit, or long eyelids cause the tarsal plate to be less rigid and fold over
< 1 y/o
What causes cicatricial entropion?
scarring from chemical burn or eyelid laceration causes the eyelid to roll in
What causes spastic entropion?
ocular pain causes globe retraction, which no longer supports the eyelid
- small component of all types of entropion
When is entropion surgically repaired? What should be done before repairing?
wait to 8 months to a year, until the head is fully grown, unless there is significant corneal disease
evaluate entropion with and without topical anesthesia (proparacaine)
How can spastic entropion be ruled out?
place proparacaine in eye to resolve pain
- with proparacaine in, spastic entropion will no longer be present
- can also place temporary tacking sutures and re-evaluated after painful process (ulcer) resolves
What is a temporary option for treating entropion?
tacking sutures left for 4-6 weeks —> pulls eyelids away from eye to allow healing of ulcers to rule out or in hereditary entropion
- persistent entropion requires further intervention
In what animals are tacking sutures most commonly used? What pattern is used?
Shar-Pei and Chow-Chow puppies
vertical mattress pattern using 4-0 silk or nylon
What is the most common permanent repair method for entropion? How is it performed? What is the goal?
Hotz-Celsus procedure —> incise 2-2.5 mm from the eyelid margin, extending 1 mm medial and lateral to the entropic part, creating an ellipse the size necessary to roll back entropion
roll the eyelid margin into the normal position
What occurs if incisions are made too close or too far from the eyelid margin in the Hotz-Celsus procedure? What should be done if the patient has long eyelids?
- too close = nothing to suture
- too far = eyelid will not roll out
may need to be shortened with a small wedge resection
How does the occurrence of entropion in cats compare to dogs? How does age relate to cause?
rarer compared to dogs, most common in Maine Coons and Persians (facial folds!)
- YOUNG - more likely to start as spastic due to conjunctivitis or herpesvirus (chronic inflammation)
- OLDER - decreased orbital fat
What is ectropion? What breeds are predisposed? What are 2 common causes?
eversion of eyelids
Neopolitan Mastiff, Hound dogs, Great Danes —> naturally droopy eyelids
- overcorrection of entropion
- form of macropapebral fissure syndrome (“diamond eye”)
How is ectropion treated?
typically not repaired, as it does not cause clinical problems; will be corrected with chronic conjunctivitis or if it was the result of entropion overcorrection
- often breed standards
What is the difference between distichia and ectopic cilia?
DISTICHIA = cilia grows out of Meibomian gland opening (B)
ECTOPIC CILIA = cilia puncture through conjunctiva (C)
Distichia vs ectopic cilia:
What breed is most commonly affected by distichia or ectopic cilia? What age is most commonly affected?
Shih Tzu (also Boxer, English Bulldog, Pekingese, Cavalier King Charles Spaniel)
younger dogs (<1 y/o)
How can ectopic cilia be seen on the conjunctiva?
hair grows from a pigmented conjunctival spot, indicative of irritation
How is ectopic cilia treated?
use a 2 or 4 mm punch biopsy to make a partial-thickness incision punch and remove fully with tenotomy scissors and Bishop Harmon forceps —> left open, no sutures
What eyelid tumor is most common in dogs? What are some others?
BENIGN —> Meibomian gland adenoma (>10 years)
- adenocarcinoma
- histiocytoma
- melanoma (pigmented lids)
- papilloma
- mast cell tumors
What 2 eyelid tumors are most common in cats? What others can be rarely seen?
MALIGNANT —> SCC, MCT (ulcerated)
- HSA
- peripheral nerve sheath tumor
- adenocarcinoma
- lymphoma
In what animals are viral eyelid papillomas most common? How are they treated?
younger animals (differentiated from SCC), can be pigmented without relationships with oral
- spontaneous regression possible
- surgical removal, cryotherapy
- interferon
What treatment is preferred for Meibomian gland adenomas? What are 3 options?
removal with 1 mm margins —> benign, does not require large margins
- cyrotherapy ablation
- CO2 laser ablation
- wedge resection
What treatment is preferred for melanomas and MCTs?
more extensive removals with skin flap construction to reconstruct margins (H-plasty)
What 2 types of wedge resections are commonly done for benign eyelid tumors? How do they compare?
- V-shaped
- four-sided - takes out less margin
- small margins ~1 mm on each side (full thickness!)
How are wedge resections closed?
2 layer closure (SQ and skin), achieving perfect apposition with a figure of 8 suture pattern where the knot is tied away from the margin to avoid irritation and corneal ulceration
In what cats are eyelid tumors most common? Which malignant and benign tumors are most common?
older cats
- MALIGNANT = SCC in white cats
- BENIGN = apocrine hidrocystoma (smooth, enlarged eyelid glands)
What is a chalazion? What is the most common cause? How is it treated?
non-neoplastic enlargement of the Meibomian gland filled with lipids
adenomas causing duct blockage
- removal of tumor causing the blockage
- incision and drainage
How must all eyelid lacerations be repaired? How is it performed?
primary closure —> second intention can cause entropion, notch defect, or trichiasis
- remove the least amount of eyelid as possible (very specialized tissue that needs to be conserved)
- appose with figure of 8 sutures at lid margin
What is blepharitis? Why is this especially common?
eyelid inflammation
eyelids are very vascular, so they are prone to exaggerated inflammatory responses
What are some possible causes of blepharitis?
- Sarcoptes, Demodex
- Dermatophytosis
- autoimmune disease
- bacterial infection
- atopy
What is required to properly diagnose blepharitis? How are they most commonly treated?
- complete dermatologic examination
- biopsy
medically
What is Meibomiantitis? What are 4 common presentations?
purulent bacterial infection of the glands of Zeis and Moll (AKA Hordeolum, marginal blepharitis)
- discharge and painful
- swelling of eyelids due to enlarged Meibomian glands
- alpoecia
- inflammation of multilpe glands
