Eyelids & Third Eyelid Flashcards
1
Q
When do the eyelids develop during gestation? What are they developed from?
A
Develop around day 25 of gestation
Grow towards each other and elongate to cover developing eye
Meet and fuse together by day 40
Eyelid epidermis, cilla, lacrimal gland, nictitans gland, meibomian glands and sweat/sebaceous glands (glands of Moll and Zeis) all derived from surface ectoderm.
Neural crest mesenchyme contributes to development of tarsal plate and dermis
Eyelid muscles derived from mesoderm
2
Q
When do puppies/kittens first open their eyes post birth?
A
Eyelids separate day 10-14 postnatally
3
Q
What layers are there within the eyelids?
A
1.Haired eyelid skin on outer surface
2. Muscle extending to a fibrous tarsal plate containing meibomian glands (tarsal plate poorly developed in dog, more developed in the cat)
3. Palpebral conjunctiva on inner surface extending to conjunctival fornix where reflects to become bulbar conjunctiva covering sclera.
4
Q
Describe the arrangement of cilia (eyelashes) in the dog and cat.
A
Upper eyelid = two or more rows of cilia in the dog, cats first row of skin hairs is more developed and act as cilia
Neither cats nor dogs have cilia on bottom eyelids
5
Q
Which muscle controls the closing of the eyelids? Which eyelid is more mobile - upper or lower?
A
Orbicularis oculi = closure of the palpebral fissure and enables blinking
(Upper eyelid more mobile than lower eyelid - greater coverage of cornea with each blink)
6
Q
What is the innervation to orbicularis oculi (muscle responsible for closure of the palpebral fissure)?
A
Palpebral branch of the auriculopalpebral nerve - branch of the facial nerve (CN 7, VII)
7
Q
Which muscles are involved in opening of the eyelids?
A
Levator palpebrae superioris (upper eyelid)
Pars palpebralis of sphincter colli profundus (lower eyelid)
Muller muscle (upper eyelid)
8
Q
Which nerve innervates the levator palpebrae superioris? What benefit does this innervation have in relation to another structure of the eye?
A
Innervated by occulomotor nerve (CN III)
Occulomotor also innervates the dorsal rectus EOM - means that upper eyelid lifts at same time as globe elevated.
9
Q
Which nerve innervates the pars palpebralis of sphincter colli profundus?
A
Dorsal buccal branch of facial nerve (CN VII)
10
Q
What is the innervation to the Muller muscle?
A
Smooth muscle = sympathetic innervation
11
Q
Where do the upper and lower eyelids meet? How is this structure stabilised?
A
Meet at the canthi - medial and lateral canthus
Medial and lateral canthal tendons to stabilise + retractor angularis oculi muscle
12
Q
Describe the medial and lateral canthal tendons.
A
Medial canthal tendon = distinct fibrous band originating from periosteum of frontal bone
Lateral canthal tendon = musculofibrous band lying subconjunctivally connecting to muscle at lateral canthus to orbital ligament
13
Q
How is sensation provided to the eyelids?
A
Branches of the ophthalmic and maxillary nerves originating from the trigeminal (CN 5)
Ophthalmic nerves = mainly medial
Maxillary = mainly lateral
but is some overlap
14
Q
What reflex will be absent if there is loss of sensation to the eyelids?
A
Trigeminal lesion - loss of palpebral reflex
Assess palpebral at both medial and lateral canthus
15
Q
How can you differentiate the loss of the palpebral reflex due to a trigeminal or a facial nerve lesion?
A
Observation of spontaneous blinking - indicates facial nerve intact (innervates orbicularis oculi - muscle responsible for blink)
16
Q
What does the grey line or margo-intermarginalis represent?
A
Slight groove - opening of meibomian glands
17
Q
What are the meibomian glands - how many are there per eyelid and what do they secrete?
A
Modified sebaceous glands
20-40 glands per eyelid
Visible through palpebral conjunctiva when eyelid everted
Produce meibum - lipid faction of the tear film
18
Q
What is the role of meibum in the tear film?
A
Meibum = liquid at body temperature
Expressed from meibomian glands during blinking
Decreases surface tension of tear film drawing water in and increasing tear film thickness.
Reduces evaporation and coats eyelid margins to minimise tear overflow onto eyelid margin itself.
19
Q
What are the glands of Moll & Zeis?
A
Moll = modified sweat glands
Zeis = sebaceous glands associated with eyelid cilia
Functional significance in animals unknown but can become infected resulting in eyelid styes/external hordeola.
20
Q
What is the caruncle?
A
Caruncle = protuberance at medial canthus from which fine hairs project
21
Q
Where is the third eyelid derived from embryonically?
A
Surface ectoderm
22
Q
Describe the anatomy of the third eyelid/nictitans.
A
Central T shaped hyaline cartilage surrounded by fibrous tissue and covered in conjunctival epithelium
Bulbar surface = lymphoid tissue beneath conjunctival epithelium + intraepithelial goblet cells
Goblet cells also present in greater number on palpebral conjunctiva of TEL
Nictitans gland located at the inferior/proximal end of the cartilage
Base of third eyelid associated with fascia of the orbital musculature and cartilage shaft is aligned with inferionasal peribulbar connective tissue.
23
Q
Does the TEL contain muscle?
A
Canine TEL = Thought to lack musculature - protrusion being passive when globe retracted and retrobulbar tissues push on base of TEL but leiomyomas have been diagnosed in the TEL indicating the presence of native smooth muscle.
Feline TEL = contains both smooth and striated muscle, can actively retract and protrude respectively
2 sheets of smooth muscle (medial and inferior muscles of TEL) arise from deep in orbit from fascia of medial and ventral rectus muscles
Medial supplied by postganglionic fibres of infrtrochlear division of ophthalmic branch of trigeminal
Inferior supplied by intraorbital/zygomatic branches of maxillary branch of trigeminal nerve
Striated muscle - arranged as leashes
Extend from levator superioris and lateral rectus - insert on dorsolateral and ventrolateral arms of TEL
Ventrolateral = abducens innervation
Dorsolateral = occulomotor
24
Q
What types of disease can cause passive protrusion of the TEL?
A
Retrobulbar/orbital disease - space occupying lesions (extraconal)
Reduced globe size = microphthalmos, phthisis bulbi
25
List the functions of the eyelids.
Protection of the eye (menace response)
Cilia and sensory vibrissae contribute to protective effect
Meibomian glands of eyelids = meibum for tear film
Goblet cells in palpebral conjunctiva = mucin for tear film
Blinking - removal of debris from ocular surface, distribution of tear film (nutrition and hydration to ocular surface), draining tear film to remove toxic waste (blinking = pressure change in lacrimal sac which draws tears into lacrimal canaliculi, as eyes open pressure put on lacrimal sac to push tears down NL duct)
26
List the functions of the third eyelid.
Nictitans gland - 30% to one third aqueous produced + Immunoglobgulin secreting plasma cells have been identified adjacent to conjunctival epithelium on both surfaces of the third eyelid - role in defence of ocular surface.
Leading edge distributes the tear film and physically removes debris from the corneal surface
27
Describe the steps of particular importance in assessing a patient for eyelid disease.
Distance exam - look for asymmetry in ocular/adnexal conformation and periocular skin changes, ocular discharge
Look at distribution of any discharge as can give clues to area of cilia contact.
Presence/absence of spontaneous blinking
Hands on focal examination with naked eye and light source +/- magnificatiojn
Eyelids examined systematically - particular attention to periocular skin, eyelid margins and palpebral conjunctiva.
Assessment of meibomian glands
Assessment of lacrimal punctae
If entropion - application of topical anaesthetic should be applied to assess for any spastic component
Corneal ulceration - look at adjacent eyelids for any inciting cause of the ulcer e.g ectopic cilia
Fluorescein - identify ulceration, TFBUT, NL patency, adheres to any facial hairs/distichia contacting corneal surface and can make easier to identify.
28
Discuss the important steps when examining a patient for suspected TEL disease.
Presence confirmed and palpebral surface + leading edge examined
Gentle globe retropulsion can be used to passively protrude TEL and check for any restriction to protrusion (prev surgery/disease)
Topical anaesthesia - examine under TEL - blunt tipped cilia forceps or micro St Martins to grasp palpebral surface and retract
Anaesthesia of the conjunctiva takes longer than cornea so optimal = application of cotton tipped swab soaked in local anaesthetic directly over area of TEL to be grasped.
29
What laboratory tests may be indicated in cases of eyelid disease?
Cytology using tape strips - identify bacteria and yeast colonisation of periocular skin
Swabs for bacterial culture/sensitivity - ulcerated skin lesions or discharge from abnormal meibomian glands
Periocular skin scrapes/hair plucks = parasitic disease
FNA - eyelid masses
Surgical biopsy - punch biopsy of periocular skin, full thickness eyelid mass wedge resection if eyelid margin involved, biopsy of eyelid masses
Biopsies - histopath +/- immunohistochemistry +/- PCR or tissue culture
30
What laboratory tests might be indicated in cases of third eyelid disease?
Cytlology of palpebral conjunctiva - topical anaesthesia and scalpel blade blunt end
Conjunctival snip biopsies after topical anaesthesia
Larger biopsies - GA, avoid leading edge of TEL as will affect TEL function
31
What can occur if the eyelids open prematurely?
Lacrimal apparatus still immature
Keratitis, corneal dessication, conjunctivitis and risk of severe corneal ulceration risking perforation and endophthalmitis
Treatment - frequent lubrication and possibly temporary tarsorrhaphy
32
What is delayed opening of the eyelids termed and why does it occur?
Ankyblepharon
Failure of bridge between two eyelids to atrophy
(Reported in Persians)
33
What is ophthalmia neonatorum? What is the recommended treatment?
Accumulation of fluid/pus beneath fused eyelids of the neonate.
Recommended tx = warm compresses and gentle digital traction to encourage eyelid opening
If conservative approach unsuccessful over 24hrs then eyelids can be very carefully prised apart using blunt ended instrument e.g fine haemostats or blunt ended scissors
NEVER incise with scalpel or scissors as will cause irreversible damage to eyelid margins
Once palpebral fissure opened topical AB ointment should be applied - lubrication + AB cover
34
Which infectious disease is associated with ophthalmia neonatorum in cats?
What complications can be seen with this type of infection?
Herpesvirus - if occurs before eyelids open conjunctival and corneal epithelium can undergo necrosis and neutrophilic response leading to accumulation of inflammatory debris in conjunctival sac distending the still fused eyelids. Can then get secondary infection on top.
Complications - symblepharon, corneal ulceration/perforation, endophthalmitis/panophthalmitis
35
What is an eyelid coloboma?
Congenital defect - partial or full thickness length of eyelid is absent (whole length = eyelid agenesis)
36
Where do eyelid colobomas usually occur in dogs?
Usually lower lateral eyelid that is missing in dogs
Can be unilateral or bilateral
Less common than in cats and may be associated with other defects e.g dermoids
37
Where do eyelid colobomas usually occur in cats?
One of the most common feline congenital abnormalities
Usually lateral upper eyelid and bilateral (medial canthal involvement also reported)
Reported in DSH, Persian and Burmese
Can vary from small notch to complete absence of tow thirds or more of upper eyelid and lining.,
38
What are the consequences of eyelid colobomas?
Increased corneal exposure - increased evaporation of tears
Poor tear film distribution
Keratitis and corneal ulceration
Trichiasis - adjacent skin hairs contact cornea
39
What treatment options are there for eyelid colobomas?
Very mild cases - regular lubrication
Cryoepilation of offending hairs if eyelid sufficient enough to function and protect cornea.
Impaired eyelid function/severe trichiasis - requires surgical correction
Small defects - wedge resection
Larger defects = more complicated grafting techniques
Option 1: Skin-orbicularis layer from lower eyelid and conjunctiva from third eyelid - graft contraction can occur and trichiasis meaning further procedure required.
Option 2: Modified 2 stage Mustarde cross lid technique - full thickness lower eyelid to reconstruct upper eyelid avoiding trichiasis associated with other methods
Lip to lid technique then used to repair defect in lower eyelid
Option 3 : Modified lip to lid technique by taking section of commissure of lip and using it to replace upper eyelid and lateral canthus - 1 stage technique, good cosmetic and function result.
Option 4: Subdermal collagen + modified Stades procedure to remove haired skin in contact with cornea
Option 5: Free oral mucosal grafts
Option 6: Subdermal hyaluronic acid injections and free labial mucocutaneous grafts.
40
What is a dermoid? How do they present and what is the usual treatment in the eyelid?
Presence of aberrant tissue containing skin
May occur as result of abnormal differentiation of group of cells or inclusion of surface ectoderm during closure of foetal clefts.
May affect conjunctiva and eyelids
Often referred to as choristomas - normal tissue in abnormal location (eyelids hamartomas)
Mostly unilateral although occasionally bilateral
Tx = removal of abnormal tissue surgically with repair and re-establishment of eyelid margin
Fissure length usually enough to allow direct closure via wedge resection without need for blepharoplastic techniques.
41
What breed has a predisposition for dermoids in cats?
Birmans/Burmese
42
What is a macropalpebral fissure? Which breeds is it commonly seen in?
Enlarged palpebral fissure
Usually bilateral
St Bernards, Neapolitan Mastiffs, Clumber Spaniels, Bloodhounds - overlong eyelids + weak lateral canthal support = ectropion frequently combined with lateral lower entropion = diamond eye appearance
Brachycephalics - orbits shallow and eyelids are taut - overlong eyelids = exposure keratitis and risk of proptosis
43
What is lagophthalmos? What can cause it? What treatment options are there?
Inability to close eyelids
Causes:
Facial nerve paralysis - prevents eyelid closure
Brachycephalics - prominent globes, macropalpebral fissure, leads to incomplete blink = central corneal dessication, poor tear film distribution, exposure keratitis with associated neovascularisation and ulceration.
May not fully be able to close eyelids even when asleep.
Cats e.g Persians = risk of corneal sequestrum formation
Tx - regular ocular lubrication (oil based tear substitutes - long lasting)
Surgery - shortening of eyelids - medial canthoplasty
44
What is a micropalpebral fissure - which breeds can it occur in?
Abnormally small eyelid fissures - Shetland sheepdog, Rough Collie, Schipperke
No tx usually indicated
Tight eyelid globe apposition can lead to reduction or abolition of lacrimal lake leading to epiphora.
45
Define distichiasis.
Distichiasis = extra eyelashes arise from follicles adjacent to meibomian gland orifices.
1 hair = distichia
More than 1 hair from single orifice - distichiasis
46
Which breeds of dog are predisposed to distichiasis?
Flat coated Retriever, Dachshund, Cocker Spaniels, Miniature Poodle, Shetland Sheepdog, Bulldog, Boxer, Cavalier, Pekingese, Weimaraner, Staffordshire Bull Terrier
47
How do you determine the significance of distichiasis?
Many distichia are fine and have had from young age - incidental findings that do not require treatment
If dog presents with ocular discomfort and distichia - perform full ophthalmic exam to rule out other causes.
Problems in older dog or unilateral issue where distichia appear equally distributed bilaterally - distichia unlikely to be responsible
If in doubt - assess response to epilation before considering permanent removal techniques.
48
What permanent removal techniques are there for distichia?
Solitary - eyelid wedge resection
Multiple distichia:
Cryotherapy
Electrolysis
Radiosurgery - specialised distichiasis wires are used to treat each follicle individually
Transconjunctival thermal electrocautery
Sharp knife surgery
49
How is cryotherapy for distichia performed? What advantages does it have?
How are these patients managed post op?
Advantages - scarring minimised and meibomian glands can recover as hair follicle differentially temperature sensitive
Good for treating more extensive areas of distichiasis and treating any un-erupted hairs at time of tx
Chalazion clamp applied to stabilise and evert eyelid, limits blood supply for more rapid freezing and slower thawing increasing effectiveness
Cryoprobe or cryospray applied transconjunctivally
Ideally thermocouple at tip to measure temperature and ensure adequate freezing of the hair follicle without permanent damage to adjacent epidermal or conjunctival surfaces.
Operating microscope/magnification improves precision.
Double freeze-thaw cycle used
Post op = eyelid swelling to be expected
NSAIDs for analgesia/anti-inflammatory
Eyelid depigmentation often occurs but should re-pigment over 2-6 months
20% recurrence rate
50
How is electrolysis performed - what are the disadvantages of this procedure for distichiasis?
Disadvantages - time consuming, scarring and distortion of eyelid margins can occur as can irreversible meibomian gland damage.
Procedure can only be used for hairs erupted at time and because distichia growth is cyclical procedure may have to be repeated as new hairs emerge.
51
How is transconjunctival thermal electrocautery for distichiasis performed?
Disposable thermal electrocautery pen used with magnification
Tip is heated and inserted into palpebral conjunctiva at level of distichia - 4mm posterior to eyelid margin and 2mm depth
Distichia then easily epilated
Glandular contents then additional distichia expressed using cilia forceps inserted into conjunctival defect
Charred tissue should be debrided to reduce risk of corneal ulceration
Complications - eyelid depigmentation/inflammation, infection, eyelid distortion, qualitative tear film abnormality
Unable to use for medial distichia due to proximity to lacrimal punctae and canaliculi
52
What is sharp knife surgery for distichiasis? What disadvantages does it have?
Lid splitting/subconjunctival resection of strip of follicles
Disadvantages = incomplete resection, eyelid distortion and/or cicatricial entropion
Hotz-celsus to direct hairs away from cornea but affects relationship between eyelid margin and ocular surface
53
What can be the consequences of distichiasis and ectopic cilia in cats - which breeds predisposed and how common?
Not very common in cats
Burmese/Siamese appear to be predisposed
Epiphora, corneal ulceration, sequestrum formation
53
What are ectopic cilia? What is the treatment for them?
Atypical form of distichia - arise from follicle inside meibomian gland or near meibomian duct.
Contrast to distichia emerge through conjunctival surface few mm from eyelid margin and are directed towards cornea.
Solitary or in small clumps
Young dogs - usually middle of upper eyelid
Often occur in conjunction with distichia
Treatment = resection en bloc using chalazion clamp and no 11 blade or 2mm biopsy punch
Surgical site can then be treated with cryotherapy to reduce reoccurrence.
54
What is trichiasis - where can these hairs originate from?
Normally located but abnormally directed hairs that contact and irritate ocular surface
-Upper eyelid cilia
- Caruncular hair
-Nasal fold/facial hair
-Hair adjacent to areas of eyelid agenesis
- Misaligned eyelid margin following trauma without surgical repair
-Misaligned eyelid margin from poor surgical repair
-Blepharoplasty techniques involving transposition of facial skin without creating an eyelid margin (Sliding lateral canthoplasty, H-plasty, sliding skin grafts)
- Abnormal eyelid position (e.g entropion)
Treatment depends on clinical significance i.e = is the trichiasis causing corneal pathology
55
What types of entropion are there?
1. Breed related/anatomical
2. Spastic
3. Cicatricial
4. Atonic/senile
56
How does anatomical/breed related entropion usually present?
Usually bilateral (occasionally unilateral)
Breeds predisposed - Shar Pei, Chow-Chow (often evident soon after eye opening)
4-12 months of age as facial conformation changes can become more evident, some cases may reduce/improve as matures.
Breed related entropion may also develop in middle aged animals, typically males - associated with s/c deposits, often upper eyelid entropion.
Optimal method of correction varies with breed/predisposing anatomy.
Entropion of this nature likely to be hereditary so dogs who have surgical alteration of facial conformation should not be bred from.
57
What is spastic entropion?
Secondary entropion that results from ocular pain
Spasm of orbicularis oculi and retraction of the globe causing eyelid to turn in.
Resultant trichiasis worsens ocular pain and retraction.
Most forms of entropion will have spastic component so important to assess post application of local anaesthetic.
58
What is cicatricial entropion?
Uncommon - results from lid distortion and scarring following injury, chronic dermatitis or inappropriate surgery
59
What is atonic/senile entropion?
Age related loss of skin elasticity and muscle tone
Often breeds that already have excessive facial skin e.g Cocker Spaniel (forehead skin droops upper eyelid cilia directed downwards - contact cornea and lower conjunctival fornix - conjunctivitis/keratitis
60
How should you assess entropion prior to performing correction?
Assess in conscious patient
Local anaesthetic applied - removes spastic component and avoids over-correction
Assess in different head positions - especially with head down as entropion/ectropion may be exacerbated by slippage of facial mask. (examination table to help)
Observation of tearing and ocular discharge will also give clues as to problematic area.
61
How can entropion be addressed in young puppies?
Corrective surgery best delayed until 5-12 months (depending on progression, breed and degree of entropion)
Eyelid conformation can change as puppy ages so some cases will self correct with time.
Temporary correction always indicated - periocular hairs rubbing on cornea = pain, globe retraction, worsening of entropion and risk ulceration/scarring and potentially perforation.
Lembert suture pattern - non absorbable interrupted sutures to create temporary eversion
Sutures perpendicular to eyelid margin
1st bite 2-3mm from eyelid margin
Several rows may be needed in breeds with excessive skin e.g Shar Pei
Sutures can be pre-placed and tissue glue placed in presumptive skin fold that will be formed before tying the sutures in order to help prolong the eversion
Sutures directed away from cornea
May need to be repeated if sutures fail or entropion recurs before puppy old enough for permanent correction
Alternatives
If just lower lateral entropion = temporary tarsorrhaphy
Skin staples (often several rows)
Hylauronic injectable subdermal filler
62
What options are there for entropion correction in adults?
No "one size fits all" treatment - depends on location of entropion and surrounding anatomy
Options include:
Hotz-Celsus (lower entropion)
Stades procedure (upper entropion)
Medial canthoplasty
Coronal rhytidectomy
Wedge resections (overlong eyelids)
63
What surgical corrections can be performed for overlong eyelids?
Wedge resection
Wedge resection + Hotz celsus
Modified Kuhnt-Szymanowski technique (support lateral canthus)
Predisposed - Chow Chow, Labrador, Shar Pei, Setters
64
What surgical corrections can be performed for excessive facial folds around the eyes)
Local excision of the skin folds
65
What surgical corrections can be performed for inverted lateral canthi due to angled traction on the lateral canthal tendon (affects lower eyelid +/- upper eyelid)
Lateral canthal tendectomy + lower eyelid wedge resection (as release of lateral canthus can lead to ectropion)
+/- Hotz celsus depending on presentation
Broad skulled breeds - Chow Chow, Labrador Retriever, Mastiff, Rottweiler
66
What surgical corrections can be performed for brachycephalic skull conformation?
Brachycephalic skull conformation associated with:
1. Nasal fold and nasal fold trichiasis - nasal fold excision
2. Excessive nasal skin folds causing medial lower+/- upper entropion - Lower +/- upper eyelid modified Hotz-Celsus
3. Medial caruncular trichiasis - resection of caruncle as part of medial canthoplasty
4. Lagophthalmos and globe exposure (macropalpebral fissure) - permanent canthoplasty - medial indicated for brachycephalics, reduces size of palpebral fissure whilst removing caruncular hairs. Can also protect from nasal fold trichiasis.
Can be combined with modified Hotz-Celsus and/or nasal fold excision
Bulldogs, Pugs, Pekingese, Shih Tzu, Persian cats
67
What surgical corrections can be performed in breeds with excessive facial droop leading to upper eyelid ptosis/trichiasis - redundant forehead skin/atonic senile entropion?
Stades procedure - remove large amounts of skin above upper eyelids
Face lift (coronal rhytidectomy) combined with eyelid techniques
68
What is diamond eye conformation and how might it be surgically addressed?
Diamond eye = overlong upper and lower eyelids + weakness at lateral canthus
(Basset Hounds, Bloodhounds, Clumber Spaniels, Great Danes, Mastiffs, Newfoundlands, St Bernards)
Tx = upper and lower eyelid shortening via wedge resection + permanent suture to put traction on and anchor the lateral canthus (modified Wyman canthoplasty)
69
What are the most common causes of entropion in cats?
Most commonly secondary to painful ocular disease = spastic entropion that fails to resolve when initiating painful disease does.
Older cats - loss of orbital volume e.g weight loss leading to enophthalmos and secondary entropion
Excessive facial jowl e.g Maine Coons can also lead to lower eyelid entropion.
Primary anatomical entropion rare in cats but can be see in Perisans.
70
What technique is often used for treatment of entropion in cats? How does performing this surgery compare to dogs?
Hotz-Celsus +/- eyelid shortening +/- lateral canthal closure
Cats = greater amount of eyelid tissue to be needs to be removed in order to resolve entropion compared to dogs.
Unilateral - may benefit from prophylactic surgery to other eye (wedge rescetion) as 17% develop in other eye.
71
What non surgical technique may be an option for entropion treatment?
Hyaluronic acid injectable sub dermal fillers (0.1-0.3mls with 27/30 G needle)
May require repeat injections
Does not require GA/sedation - ? option for high risk geriatrics
Cats - ?risk of sarcoma formation, use with care
72
What is ectropion and what clinical signs/consequences can we see due to it?
Outward turning of the eyelids
Usually breed related in breeds with overlong eyelids and laxity of lateral canthus - increased conjunctival exposure with collection of debris in lower conjunctival sac + poor tear film distribution
Conjunctivitis and increased mucin production
May be combined with entropion of lateral lower eyelid or trichiasis from upper eyelid (diamond eye) - corneal irritation/ulceration also
Can occur as a result of severe damage, scarring and cicatrix formation - severe skin disease, burns or iatrogenic following inappropriate surgery for distichiasis or over correction of entropion.
73
When is ectropion correction indicated and how can this be performed?
Indicated when conjunctival/corneal pathology occurs
Simple ectropion = wedge resection to shorten eyelid length +/- upper eyelid shortening and stabilisation of lateral canthus
More complicated eyelid shortening - modified Kuhnt-Szymanowski procedure (gives lateral canthal support)
Cicatricial entropion - V to Y plasty
74
Which breeds are predisposed to third eyelid gland prolapse?
Shi Tzu, Lhaso Apso, English and French Bulldogs, Pekingese, Shar Pei, Ameican Cocker Spaniel, Great Dane, Mastiff breeds
75
Where it the third eyelid gland usually positioned and why is it believed to be prone to prolapse?
Should you breed from individuals prone to cherry eye?
Usually positioned at base of third eyelid cartilage
Laxity of attachment of the third eyelid cartilage and periorbita as well as crowding of inferior orbital space in some brachycephalic breeds = prone to prolapse.
Genetic component suspected - not recommended to breed for individuals who have cherry eye.
76
When does third eyelid gland prolapse usually occur? What should we warn owners if only unilateral presentation?
Usually <1 year
Can be unilateral or bilateral (20-40% cases)
Often will affect other eye within 3 months if unilateral.
77
Why is removal of the third eyelid gland never recommended?
Produce approx 1/3rd aqueous tear film
Breeds predisposed often also at risk of KCS and therefore potentially have less functional reserve
78
What methods are there for replacement of a prolapsed TEL gland?
1. Morgan Pocket Technique (mucosal pocketing of gland)
2. Tacking to orbital rim periosteum
3. Tacking to episclera/scleral tissues
4. Tacking to third eyelid cartilage
5. Perilimbal pocketing
6. Anchoring to insertion of ventral rectus muscle
79
What risks/complications can be seen with third eyelid gland replacement methods?
1. Failure and re-prolapse
0-12.5% Morgan Pocket
0-25% Periosteal anchoring
58.9% inferior scleral anchoring
0% ventral rectus
0-9% other techniques in one study
2. Corneal ulceration - knots on outside of TEL to prevent contact with cornea
3. Suture reaction - typically use 6/0 vicry (Cane Corso/Mastiff may be more reactive - consider monocryl instead)
4. Lacrimal cyst formation - ensure to leave small gap at each end of suture line with Morgan Pocket technique to prevent.
N.B - additional complications with periosteal anchoring - permanent suture, possible nidus of infection/may restrict movement of TEL
80
Which cat breeds can be predisposed to prolapsed third eyelid glands and when do they typically present?
Burmese, Perisians predisposed but is also seen in the DSH
Often spontaneous isolated ocular disorder
Age of onset <1 year to 6 years
Not thought to be congenital
Surgical treatment options are the same as for dogs.
81
What is scrolled cartilage? Which breeds are predisposed?
Deformation of the third eyelid cartilage - abnormal growth leads to eversion or inversion of the third eyelid.
Occurs most commonly in large and giant breeds - fast growing
82
What effect can scrolled cartilage have on the ocular surface?
Unable to act efficiently to remove debris from ocular surface/spread tear film.
Dust, debris and foreign material may also collect if the TEL is everted leading to ocular irritation.
83
How is scrolled cartilage treated?
Surgical option:
Excision of the scrolled portion of the third eyelid by a conjunctival incision
Surgical loupes for magnification
?Use of TEL flap post op to split eyelid against contour of globe.
In some cases shortening TEL also indicated - can be done by performing wedge resections at temporal and nasal aspects of the third eyelid which are then closed with 6-0-8/0 polyglactin material
?Prophylactic pocketing of TEL gland as treating scrolled cartilage can be associated with prolapse of TEL in giant loose lidded breeds.
Non Surgical option:
Thermal cautery applied to bulbar surface of TEL overlying scrolled area to contract and straighten it.
Care not to excessively cause thermal damage to tissues and ensure abrasion of corneal surface by charred conjunctiva does not occur.
84
How would you approach a dog with concurrent TEL gland prolapse and scrolled cartilage?
Pocket technique + cartilage excision
Even better outcomes if combined with wedge conjunctivectomy in one study
Performed ventrally initially with 3-6mm wedge of TEL excised at extremity of nictitans membrane.
Cojunctival margins closed with simple interrupted non penetrating absorbable sutures.
Second wedge removed at dorsal extremity of leading edge of third eyelid if needed in order for the leading edge to be perfectly apposed to the corneal surface.
85
Why may microphthalmos lead to protrusion of the third eyelid? How may it be addressed if affecting vision?
Passive protrusion - reduced globe size within orbit
If obscuring pupil/affecting vision - shortening of TEL can be used
Resection of portion of third eyelid cartilage via conjunctival incision on the anterior surface of the third eyelid.
86
When are cysts of the third eyelid most commonly seen?
Mostly secondary to third eyelid gland replacement surgery (pocketing procedures) - due to entrapment of glandular secretions
87
List the acquired causes for third eyelid protrusion.
Enophthalmos- (cachexia/dehydration)
Microphthalmos
Retrobulbar (extraconal/non axial) disease/mass
Horner's syndrome
Sedation/anaesthesia
Dysautonomia
Cannabis intoxication
Tetanus (may be associated with "flicking" protrusion of the third eyelid)
Rabies
Torovirus in cats (often associated with relapsing diarrhoea)
88
What should all patients presenting with blepharitis or periocular dermatitis also have done?
Should also have dermatological examination - presence/distribution of concurrent skin disease may help with making a diagnosis.
89
What is a chalazion? Why do they occur?
A chalazion is a cream coloured, firm and well demarcated 2-5mm diameter swelling located in the area of the meibomian glands.
Occurs due to blockage of the meibomian glands and inspissation of its secretory products.
Visible through palpebral conjunctiva and occasionally through eyelid skin.
Generally non painful unless gland ruptures releasing contents into surrounding eyelid and setting up granulomatous inflammatory response.
90
How are chalazion treated and what can cause blockage of the meibomian glands in the first place?
Blockage of the meibomian gland duct can be due to meibomianitis, surgical trauma, neoplasia (particularly adenoma formation)
Often incidental findings - can cause frictional irritation of eye.
Treatment = lancing and cutterage of the individual chalazia via the conjunctival surface (usually requires GA)
Excision of adenoma indicated if secondary to this.
91
What is a hordeolum (stye)?
Localised infection of one or more glands of the eyelid margin, usually due to Staphylococcus infection
External hordeoleum = infection of glands of Moll/Zeiss
Internal hordeoleium = infection of meibomian gland
Usually red and painful
92
How would you treat a hordeolum?
Application of hot compresses to encourage "pointing" of the abscess
Lance once pointed (not before or manually expressed as may spread infection into surrounding tissues)
Topical/systemic broad spectrum antibiotics for 14-21 days
93
What is meibomianitis? How does it present? How is it treated?
Several meibomian glands affected concurrently
Staphylococcus infection
Presence of bacteria and immune mediated reaction to its toxin
Acute = swollen, painful eyelids with slight pointing of the meibomian glands
Gentle pressure on eyelid margin = expression of discoloured meibum - thick cheesy discharge
Can lead to loss of meibum production - increased evaporation of tear film, decreased TFBUT
Abnormal lipids produced as result of inflammatory disease can be directly toxic to cornea.
Tx = application of hot compresses
Topical + systemic AB's
(Amoxy-clav or cephalexin) - 14-21 days
Tetracycline may be beneficial owing to immunomodulatory as well as antibacterial action.
Topical/systemic corticosteroids may also be required in combination for presumed immune mediated contribution to pathogenesis and in cases with significant granulomatous inflammation.
94
Which conditions can be associated with bacterial blepharitis?
How does bacterial blepharitis present?
Atopy, parasitic disease, fungal disease, self trauma due to other chronic eyelid disease e.g entropion
Post PDT surgery - overflow of saliva
(Manage by wiping face after feeding, Triz EDTA/chlorhexidine wipes, keeping facial hair trimmed).
Diffuse superficial eyelid inflammation - hyperaemia, lid swelling and crusting with ulceration of eyelid skin and margins.
Deeper infectiom - single or multiple pyogranulomas
95
What can be the consequences of chronic bacterial blepharitis?
Chronic = can lead to scarring/fibrosis
Cicatricial entropion/ectropion
96
Which parasites can cause blepharitis?
Demodecosis (often young dogs) - non pruritic, eythematous alopecia wth comedomes and follicular casts
Cheyltiella - occasionally seen in eyelid skin in dogs receiving potent ocular steroids +/- demodex
Sarcoptes scabei - can affect periocular skin - papules, crust and scale can be seen, usually generalised skin disease
Neotrombicula autumnalis - harvest mite can cause periocular irritation in summer/early autumn.
Ticks/Otodectes - rare causes of periocular disease
Leishmania - endemic to Mediterranean countries + India/South America. Eyelids frequently involved - periocular alopecia with dry scaly lesions to diffuse eyelid thickening with hyperaemia and ulceration. May also see focal granulomas.
Diagnosis - amastigotes in lymph node, bone marrow or skin biopsy samples or by PCR testing.
Bone marrow/lymph node aspirates = highest sensitivity.
97
How can fungal disease affect the eyelid skin? How is it diagnosed?
1. Dermatophytosis - commonly affects face particularly above eyelids.
Microsporum canis/Trichophyton mentagrophytes
Diagnosis = Wood's lamp (only some cases of Microsporum fluoresce), microscopic exam of plucked hairs, fungal culture
2. Malasezzaia pachydermatis - facial pruritus and erythema, secondary infection with generalised skin disease especially atopic dermatitis.
Chlorhexidine wipes for prophylaxis.
3. Systemic fungal infections (rare in UK) - Cryptococcus, Histoplasma, Blastomycoses, Coccidiomycoides.
98
What types of allergic skin disease may lead to blepharitis +/- meibomianitis?
Atopic dermatitis - diagnosis, hx, young dogs, intradermal allergy testing
Food hypersensitivity - exclusion of other likely causes, elimination diet trial
Contact hypersensitivity - topical ophthalmic medications (gentamicin/neomycin containing preparations, ciclosporin preparations, topical carbonic anhydrase inhibitors - dorzolamide pH 5.6 acidic so more so than brinzolamide pH 7.5.
99
Which immune mediated conditions can lead to blepharitis in the dog?
Medial Canthal Ulcerative Dermatitis
Uveodermatological Syndrome (also known as Vogt - Koyanagi - Harada like syndrome)
Pemphigus complex - foliaceus, erythematosus, vulgaris
Canine lupus erythematosus
Juvenile cellulitis
100
How does medial canthal ulcerative blepharitis present and which breeds are predisposed?
How is it diagnosed and treated?
Bilateral medial canthal erosions of upper and lower eyelids
GSD (may be seen with pannus/plasmoma), Long haired Dachshund (may be seen with punctate keratitis), Toy and Miniature Poodle
Diagnosis - clinical signs and skin biopsy - lymphocytic and plasma cell infiltrates
Tx - responsive to topical antibiotics and corticosteroids
Alternative immunomodulatory tx = topical/systemic ciclosporin/ tacrolimus
101
What is uveodermatologic syndrome and which breeds are predisposed? How does it present? How is it diagnosed and what is the treatment?
Presentation - dermatological lesions affecting mucocutaneous junctions = primarily eyelid, lips, nasal planum.
Depigmentation of hair and skin (poliosis and vitiligo), ulceration and crusting.
Other ocular signs - panuveitis (anterior uveitis, chorioretinitis), retinal detachment and secondary glaucoma.
Clinical signs attributed to immune mediated destruction of melanocytes.
Diagnosis - signalment/clinical signs (combination of bilateral ocular inflammatory disease with well defined distribution of skin changes)
Skin biopsy - lichenoid interface dermatitis with infiltration by histiocytes, lymphocytes and plasma cells and multinucleated giant cells.
Adult dogs - Akita, Chow Chow, Siberian Husky, Samoyed
Tx = immunosuppression
Prednisolone + azathioprine + topical medication to manage the uveitis/glaucoma.
Long term prognosis = poor and tx does not usually prevent glaucoma and vision loss
Prednisolone + systemic ciclosporin may result in better outcome but can be cost prohibitive especially in large breed dose predisposed. Oral ketaconzole may lower required oral dose of ciclosporin.
102
How do the pemphigus complexes present, how are the diagnosed and how are they treated?
Pemphigus foliaceus & erythematosus = common, lesions develop on face and ears initially.
Erythematous macules that progress to pustules then rupture leaving erosions, scaling, crusting and hypopigmentation. Variable pruritus
Pemphigus vulgaris = rare, intraepidermal vesicles or bullae develop
Diagnosis = skin biopsy and histopathology
Immunohistochemistry can be useful
Tx = long term topical and systemic corticosteroids with administration of additonal immmunosuppression e.g azathioprine or other agents in refractory cases.
Eyelid surgery may be necessary if chronic eyelid disease leads to cicatricial entropion.
103
How does canine lupus erythematosus present? How is it diagnosed and treated?
Facial dermatitis - crusts, depigmentation, erosions and ulcers.
Nasal planum, muzzle, eyelids and lip margins. Usually bilateral and symmetrical.
Discoid and systemic types - in systemic there will be clinical signs of other organ involvement.
Diagnosis = skin biopsy + histopath
Tx = topical immunosuppressive drugs initially
Systemic prednisolone in refractory cases
Avoidance of sunlight as UV exposure may play role in pathogenesis.
104
How does juvenile cellulitis (puppy strangles) present? How is it treated?
Bilateral granulomatous pustular blepharitis with submandibular lymphadenomegaly.
Dogs <8 months old
Often also facial swelling around lips, muzzle and pinnae
Presumed hypersensitivity to bacterial toxins
Usually diagnosed on clinical signs
Dachshund, Golden Retrievers, Labradors, Gordon Setters and Lhaso Apso predisposed.
Tx = early and aggressive systemic therapy with immunosuppressives = prednisolone
Required to prevent permanent scarring
Tx tapered after resolution
Systemic bactericidal AB's indicated if cytological or clinical evidence of secondary bacterial infection.
105
How does Zinc responsive dermatitis present?
Periocular alopecia, crusting and erythema - secondary to Zinc deficiency
Northern breeds prediposed - Husky, Malamute, Samoyeds- inability to utilize or assimilate zinc or if diet deficient in zinc
Diagnosis = skin biopsy/response to therapy
106
List the causes of blepharitis/periocular dermatoses in cats.
Localised abscessation - cat fight injuries
Mycobacterial disease - feline TB (non healing discharging cutaneous nodules on eyelids and other areas)
Feline Pox Virus - periocular nodules, papules, crusts and ulcerative plaques. May be other systemic signs - pyrexia, conjunctivitis, respiratory signs.
Feline Herpes Virus - ulcerative facial and nasal dermatitis can develop as dermatological mainfestation of feline herpesvirus. Occurs 10 days after classical signs of herpes.
Demodex (rare in cat) - generalised demodecosis may be found in Siamese/Burmese associated with diabetes, leukaemia virus, SLE, hyperadrenocorticism or FIV. D.gatoi may be pruritic.
Dermatophytosis (fungal) - mostly microsporum canis, young cats <1 year and long haired Persians/Himalayans are predisposed. 1 or more irregular areas of alopecia with/without scaling. Woods lamp, microscopic exam and hair plucks/fungal culture to diagnose.
Deep mycotic disease (cryptococcus, histoplasma, blastomycoses, coccidomycoides) - rare in UK
Lipogranulmatous conjunctivitis - multiple smooth non ulcerated cream/white subconjunctival masses within palpebral conjunctiva adjacent to eyelid margins. Typically older cats 6-16yrs, white/predominately white cats.
May cause chronic ocular discomfort.
Medical tx - systemic and topical AB preparations, may reduce but not eliminate discomfort.
Surgical treatment - 2x incisions in palpebral conjunctiva parallel to eyelid margin, depth equal to that of lesions. Strip of conjunctiva and subconjunctival tissue containing lesions removed. Wound left to heal via secondary intention. Post op topical AB's.
Thought to be reaction to sebaceous secretions from damaged/ruptured meibomian glands.
Associated with lack of pigment in eyelids may indicate involvement of actinic radiation in pathogenesis.
Pemphigus foliaceus - erythematous macules to pustules then dried brown crusts. Starts on head and ears and then progresses to footpads - generalised within 6 months.
Idiopathic facial dermatitis in Persians - chronic facial dermatitis, symmetrical black waxy material adherent to hair and skin of chin, perioral and periocular areas. Erythema + exudation - pruritus develops as affected areas become progressively more inflamed and secondarily infected. Aetiology unknown.
Often poorly responsive to antimicrobials/steroids.
107
What is plasmoma? Which breeds are predisposed and how is it treated?
Plasma cell infiltration of the third eyelid conjunctiva.
Immune mediated disease of unclear pathogenesis.
GSD, Belgian Shepherds, Collie breeds over-represented
Often seen concurrently with chronic superficial keratitis (CSK - pannus)
Non painful - generalised thickening of third eyelid
Depigmentation of third eyelid leading edge
Nodular pink-tan infiltrates (predominately plasma cells with some lymphocytes)
Clinical presentation - usually enough to make diagnosis
Cytological smears - mixed population of inflammatory cells (lymphocytes and plasma cells)
Tx = 0.2% ciclosporin (optimmune) BID +/- topical corticosteroids to achieve remission (taper dose)
Long term ciclosporin often required.
108
What changes may be seen to the third eyelid in cases with generalised conjunctivitis?
Chemosis
Hyperaemia
Lymphoid follicle formation - common in patients with chronic conjunctivitis
Symblepharon
109
How do immune mediated granulomatous diseases affect the third eyelid?
Nodular granulomatous episclerokeratitis (NGE)
Idiopathic granulomatous disease
Nodular fascilits
All thought to represent different forms on a spectrum of related immune mediated diseases.
NGE - does not usually involve conjunctiva (granulomas subconjunctival) but may involve TEL. Collie's overrepresented. Histopath = chronic granulomatous infiltrate.
Surgical excision = often recurrence but may have better success when combined with cryotherapy. Azathioprine +/- steroids also reported to be successful.
Idiopathic granulomatous disease - can involve conjunctiva and TEL + eyelids, skin and nasal mucosa. American Cocker, Collies, Shetland Sheepdogs predisposed
Immunosuppressives = tx +/- surgical debulking or excision.
110
Describe eosinophilic conjunctivitis in the cat. How can it affect the third eyelid?
Eosinophilic conjunctivitis +/- keratoconjunctivitis
Immune mediated condition - eosinophils infiltrate the conjunctiva and cornea
Creamy white to mucopuruelent to caseous exudate (resembling cottage cheese) overlying conjunctiva
Erosive/depigmented eyelid margin
Blepharospasm + conjunctival swelling
Can involve TEL as part of more extensive conjunctival +/- corneal infilatration may also see just confined to third eyelids alone - in these cases bilateral and symmetrical in presentation.
Diagnosis = cytology of a smear of infiltrate - eosinophils (also accompanied by eosinophilic granules, plasma cells and neutrophils)
?possible link to FHV-1
? associated with novel chlamydial organism (Neochalmydia hartmannellae)
Tx options:
1. Topical steroid (prednisolone acetate)
2. 0.2% Ciclosporin (optimmune)
3. Megestrol acetate in refractory cases - s/e = increased risk mammary hyperplasia, diabetes, adrenal gland suppression, endometrial hyperplasia, pyometra - not recommended first line treatment)
4. Systemic steroids in refractory cases
111
Are the majority of canine eyelid tumours benign or malignant?
75% benign in dogs (eyelid tumours)
Average age = 8 years
112
What are the most common types of eyelid tumour in the dog?
Sebaceous gland adenoma
Meibomian gland adenoma
Squamous papilloma
Benign melanoma
Sebaceous adenocarcinoma/histiocytoma
Mast cell tumour
Basal cell carcinoma
Fibroma/fibrosarcoma
Malignant lymphoma
Neurofibroma/fibrosarcoma
113
Describe meibomian gland adenoma/adenocarcinoma.
How would you treat?
Approx 40% eyelid tumours in dogs
Lobulated, pigmented and friable - often bleeding/crusting
Erupts through eyelid margin - can block meibomian gland duct leading to secondary chalazion formation and potentially granulomatous response if pushed into surrounding eyelid tissue.
Adenocarcinomas = increased mitotic activity but generally benign in this location
Short course systemic anti-inflammatory/antibiotic therapy if significant granulomatous reaction prior to surgery.
Eyelid margin should be everted and full extent of tumour assessed before removal.
Surgery = most can be removed with full thickness 4 sided wedge resection
Debulking/cryosurgery may be considered if large
Carbon dioxide laser ablation under local anaesthesia in elderly patients where GA not an option has also been used.
114
Describe papillomas of the eyelids in dogs. How are they treated?
Viral papillomas = typically young dogs
May see with oral or generalised papillomatosis
Superficial, pedunculated and typical verrucose appearance.
Can also appear as solitary lesions in older dogs
Tx = surgical removal if rapidly growing and irritating cornea.
Excision - wedge resection, cryosurgery or combination of both.
Can spontaneously regress in young dogs
115
Describe eyelid melanomas in the dog. How are they treated?
Superficial - eyelid skin or margin
Single or multiple pigmented masses
Behave more benignly than melanomas in the oral cavity or other sites.
Surgical excision with wedge resection usually curative but can also be treated with cryosurgery.
116
Describe eyelid histiocytomas - how are they managed/treated?
Typically young dogs
Develop rapidly
Raised, pink and hairless, sometimes will ulcerate and generally <1cm diameter
Can be diagnosed by FNA
Usually spontaneously regress but can take anywhere from 6 weeks to 10 months.
Surgical excision or cyrosurgery = curative for cutaneous histiocytoma and recommended for any mass not spontaneously regressing within 3 months
117
Describe mast cell tumours in the canine eyelid. How are they graded?
What is the median survival time for MCT?
What additional prognostic indicators are there?
Usually solitary masses (although can present with multiple)
Older dogs (mean age 9 years) but occasionally appear in young dogs <1 year
Breeds predisposed - Boxers, Retrievers, Pugs, Boston Terriers, Pit Bull Terriers, Shar Peis = higher risk
Boxers and Pugs usually low grade
Shar Pei/young dogs - often higher grade poorly differentiated and aggressive
Graded on histopathology
Kuipel classification system for grading (replaced Patnaik) - divides into high grade and low grade for cutaneous MCT
High grade (any of the following) = >7 mitotic figures in 10 HPF, >3 multinucleate cells in 10 HPF, >3 bizarre nuclei in 10 HPF, karyomegaly and anisokaryosis
Low grade = absence of above features
90% cutaneous MCT low grade (however 5% of these dogs will still die due to MCT related disease and 15% will already have spread to regional LN's, 20% will develop additional MCT that represent metastasis or de novo masses)
Median survival time = <4 months for high grade MCT, >2 years for low grade
Prognostic indicators - mutations in c-kit gene and altered expression of KIT as these are potential candidates for therapy with tyrosine kinase inhibitors
118
How are canine mast cell tumours graded?
Stage 1 = solitary tumour confined to dermis which have not metastasised to local LN's or internal organs
Stage 2 = MCT confined to dermis but also involve regional lymph nodes (survival time 0.8 years compared to 6.2 years with stage 1 so important to differentiate) - should perform staging for all MCT regardless of grade as 15% low grade will have spread to LN's
Stage 3 = Multiple dermal tumours or large infiltrating tumours with or without regional LN involvement
Stage 4 = MCTs have distant metastasis
119
How should surgical excision be approached for dogs with eyelid mast cell tumours?
Diagnosis of MCT on eyelid can often be obtained through FNA but cytological grading does not always correlate with histological grade
Usually recommended 2cm margins + one fascial plane for MCT elsewhere on body but this is not possible on eyelid making surgical resolution more challenging.
Ideal approach - punch biopsy of MCT at same time as staging (FNA local LN's and abdominal ultrasound with FNA of liver/spleen)
Findings = low grade and no metastatic spread = excision with appropriate surgical technique in combination with removal of the sentinel lymph node (lymphoscintigraphy and injection of vital dye around tumour)
Findings = high grade or already spread, marginal excision combined with chemotherapy would be indicated.
Neoadjunctive chemotherapy or prednisolone therapy can make more amenable to surgery.
120
How can epitheliotropic lymphoma present on the canine eyelid?
Usually affect eyelids as part of generalised disease - can be present with eyelid depigmentation and ulceration as only signs.
121
How do mesenchymal hamartoma's present in the eyelids of dogs?
Benign mass lesions made up of fully differentiated but disorganised tissues normally present in the affected areas.
Proliferative lesion forming nodules
Non neoplastic- growth limited and retain their size with no further expansion
Often adherent to underlying orbital rim, other cases freely palpable between skin and conjunctiva
Middle aged and older dogs
Predisposition for lateral canthus
FNA/cytology inconclusive
Complete excision curative in most cases but recurrence reported
122
What options are there for the treatment of eyelid tumours?
Surgical excision
Cryotherapy
Surgical excision or debulking + cryotherapy
Basic principles of oncological surgery should be applied - aim for complete resection with margins and minimal handling of adjacent healthy tissue.
123
How would you usually treat an eyelid tumour <1/3rd the length of the eyelid margin?
Wedge or four sided full thickness resection
Direct closure of defect with figure of 8 suture at the eyelid margin.
Resection should be at least 1mm or 1 meibomian gland beyond margins of the tumour.
124
What options are there for surgical removal of an eyelid mass >1/3rd length of upper eyelid margin?
1. Sliding lateral canthoplasty + full thickness 4 sided resection (new eyelid margin formed from haired skin so can result in trichiasis although restricted to lateral globe. Triangle opposite direction to lid e.g upper eyelid mass triangle down, lower eyelid mass, triangle up)
2. H-blepharoplasty, temporal horizontal H figure sliding skin flap, Z blepharoplasty, rhomboid graft flap, semi circular sliding skin flap = partial thickness grafts and may benefit from being lined by conjunctiva transposed from the adjacent eyelid, third eyelid or oral mucosa.
Advantage = single procedure
Disadvantage = trichiasis, contracture and scarring, reconstructed eyelid can lack strength
3. Mustarde technique - large upper eyelid defect.
Advantage = creates normal smooth eyelid margin
Disadvantage = 2 stage procedure requiring 2 anaesthetics
Transposition of part of lower eyelid to upper eyelid in first surgery leaving it attached by a pedicle
Second surgery - pedicle sectioned and upper eyelid reconstructed whilst lower defect is repaired using H plasty or lip to lid technique (original description).
This step can be simplified by sharing the lid deficit e.g upper eyelid defect 50% of eyelid length, 25% of lower eyelid transposed.
Benefit of sharing lid deficit = both eyelids repaired by direct apposition leaving both eyelids with 66-75% original length and avoiding need for complicated lower eyelid reconstruction with potential for trichiasis.
4. Split eyelid flap (defects up to 50%) - aims to still retain smooth eyelid margin along complete eyelid
Residual eyelid margin incised through openings of meibomian glands from border of defect for distance equal size to defect. Incision then deepened through meibomian glands through the tarsal plate by sharp then blunt dissection to elevate a flap of skin which is mobilised and transposed into the defect.
Eyelid in area of defect contains outer aspect of eyelid margin and tarsal plate, area from where flap transposed retains conjunctiva and inner eyelid margin.
Skin flap then created from adjacent eyelid skin and rotated to fill defect.
Advantage = avoids trichiasis
Disadvantage = damages significant proportion of meibomian glands that have not been excised.
5. Free tarsomarginal autograft (taken from ipsilateral or contralateral eye) combined with myocutaneous H flap.
Advantage = replaces eyelid margin with anatomically similar new margin whilst being single procedure.
125
What options of surgical repair are there for lower eyelid margin defects >1/3rd of eyelid margin length?
1. Wedge resection with sliding lateral canthoplasty - disadvantage trichiasis
2. H blepharoplasty, Z blepharoplasty, rhomboid graft flap - partial thickness grafts (may benefit from lining with conjunctiva transposed from adjacent eyelid, TEL or oral mucosa) - still potential for trichiasis
3. Mucocutaneous Subdermal Plexus Flap from lip (lip to lid graft) = preferred for large defects of lower eyelid - creates hairless, smooth eyelid margin
4. Tarsomarginal grafts also been reported for the repair of larger lower eyelid defects.
Lower eyelid less mobile so incidence of keratitis/trichiasis associated with these techniques lower.
126
When may secondary intention healing be ok in the eyelids? When is it not ok and reconstruction is always required?
Should lower eyelid reconstruction not be possible for any reason then functional results can be seen with allowing for secondary intention healing (but should not be first choice for management = always try to repair)
Upper eyelid wounds, reconstruction failures or in breeds with prominent globes - never appropriate as lack compensatory mechanisms required to allow good functional tear film distribution without lower eyelids
127
When may enucleation/exenteration be performed with respect to eyelid neoplasia?
Although majority of eyelid neoplasms benign some will be locally invasive and require much larger surgical margins than can be repaired.
In these cases enucleation/exenteration may be indicated
Sometimes will leave defect that cannot be closed in primary fashion
Surgical planning imperative in these cases - caudal auricular axial pattern flap
128
Are feline eyelid neoplasms more likely to be malignant or benign?
Feline eyelid neoplasia = most often malignant
Most commonly cats >10 years
129
What are the most common types of eyelid neoplasia in the cat?
Squamous cell carcinoma
Mast Cell Tumour
Peripheral nerve sheath tumours
Haemangiosarcoma/haemangiomas
Adenocarcinomas
Lymphoma
Apocrine hidrocystomas (often Persians)
130
Describe squamous cell carcinomas in the cat.
Most common eyelid neoplasm in cats
Raised or depressed ulcerative lesion with variable crusting on or adjacent to eyelid margin
Exposure to sunlight = predisposing factor
Seen more commonly in white cats
Metastasis not seen until late on but local invasion is often extensive and regional lymph nodes eventually involved.
Tx = surgical excision, cryotherapy, radiotherapy, photodynamic therapy and electrochemotherapy
SCC with adnexal (and/or orbital) involvement reported to have clinical signs consistent/mimicking Feline Restrictive Orbital Myofibroblastic Sarcoma (FROMS) and should be a differential for cats with restrictive adnexal (thick eyelids with poor movement) or orbital signs and corneal changes.
131
Describe mast cell tumours in the cat.
MCT - older and geriatric cats
Haired skin of eyelid
In cats cutaneous MCT generally have benign clinical course even when histologically pleomorphic
Low rate of recurrence after surgical excision even after incomplete excision
Comparable results with strontium 90 radiation and combination therapy may be warranted where surgical margins cannot be achieved
132
Describe peripheral nerve sheath tumours in the cat.
Peripheral nerve sheath tumours = spindle cell neoplasms arising from neural sheath of peripheral, cranial or autonomic nerves.
Also referred to as neuromas/neurofibromas
Upper eyelid more commonly affected and local recurrence very common.
Conservative excision with strontium plesiotherapy has been shown to provide good local control
Wide surgical excision combined with enucleation or exenteration may be indicated in early stages if adjunctive radiotherapy not an option.
133
Describe haemangiosarcomas/haemagiomas in cats eyelids.
Despite histopath features of malignancy generally favourable outcome when excised completely
May have associated with UV radiation and more commonly seen in unpigmented epithelium .
134
What is the prognosis for feline adenocarcinomas of the eyelid?
Aggressive tumours
Incomplete excision invariably followed by death or euthanasia
Highly invasive
135
What is the prognosis for eyelid lymphoma in cats
Not very common but when does occur = poor prognosis
136
Describe apocrine hidrocystomas in cats. Which breed is commonly affected?
What treatment is there?
Adenomatous proliferative tumours of apocrine sweat glands of the eyelids (glands of Moll)
Multiple circumscribed tense to fluctuant smooth nodular structures 2-10mm in diameter located in upper and lower eyelid skin
Older cats
Breed predisposition = Persians
Tx = monitoring, drainage alone, drainage and cryotherapy, surgical excision.
Recurrence rate high following both drainage and subsequent cryotherapy and surgical excision.
137
What is the only indication for third eyelid resection/gland resection?
Neoplasia
138
What types of neoplasia can affect the third eyelid?
TEL neoplasia generally uncommon
Primary:
Adenocarcinoma/adenoma
SCC
Melanoma
Histiocytoma
MCT
Papilloma
Haemangioma/haemangiosarcoma
Angiokeratoma
Plasmacytoma
MALT lymphoma
Peripheral nerve sheath tumour
Leiomyoma
Basal cell carcinoma/adenocarcinoma
Epitheliotropic lymphoma
TVT
Secondary:
Lymphoma
Metastasis and tumour recurrence rates = higher for feline third eyelid tumours compared with canine TEL tumours. Overall survival times also less.
139
How should eyelid trauma cases be managed? What are the most common causes?
Most common cause = RTA, bite wounds/fight wounds
First - full PE and ocular examination to check for other concurrent injuries and prioritise
Reconstructive surgery should be performed as soon as patient stable.
Saline irrigation to initially clean and remove debris then prepared with povidone iodine solution
Eyelid skin = excellent blood supply allowing healing for even contaminated wounds
Ischaemia/devitalisation unusual
Primary closure should be performed with minimal mechanical debridement.
NL system = cannulate to maintain patency
If NL system injured - also repair and leave indwelling cannula for 7-10 days post op
Aim = restore eyelid margin and eyelid globe apposition
If eyelid swelling prevents blinking then temporary tarsorrhaphy or application of ocular lubricants is indicated.
140
How should trauma to the third eyelid be managed?
Generally heals with minimal intervention
Trauma involving free margin or disrupting large part of TEL should be repaired surgically taking care to precent the sutures from rubbing on the cornea.
141
What types of neurological disease can affect eyelids?
Facial nerve paralysis - denervation of orbicularis oculi muscle, failure to close eyelids and blink, increased size of eyelid fissure.
Chronicity - fibrous contraction of orbicularis oculi occurs resulting in smaller palpebral fissure which is sometimes confused for blepharospasm.
Ptosis (drooping of the eyelid) can be seen with denervation of levator palpebrae superioris which is innervated by oculomotor nerve. Usually combined with denervation of EOM that are also innervated by oculomotor nerve (external ophthalmoplegia). Where oculomotor fibres to the pupil are also affected = fixed dilated pupil (total ophthalmplegia)
Horner's syndrome - denervation of Muller's muscle in both upper and lower eyelids. Leads to Ptosis of upper eyelid and reverse ptosis of lower eyelid with resulting narrowing of palpebral fissure.
142
Which neurological diseases can affect the third eyelid.
Abducens nerve denervation of ventrolateral arm leash of lateral rectus derived striated muscle in the cat prevents active TEL protrusion.
In contrast oculomotor nerve denervation of dorsolateral leash of levator palpebrae superioris derived striated muscle in cat does not prevent active TEL protrusion.
Horner's syndrome - passive protrusion as a result of loss of periorbital smooth muscle tone and enophthalmos
In cats TEL protrusion may be enhanced by sympathetic denervation of third eyelid smooth muscle
Other disease:
Tetanus
Dysautonomia
Haw's syndrome
143
What are the main aims of any eyelid surgery?
Preservation of normal anatomical relationship between the lid margins and the tear film/cornea. (Best done by using appropriately sized surgical instruments, magnification and appropriately sized suture material)
Accurate alignment and apposition of lid margin
144
When would a nasal fold excision be indicated?
Draw a diagram to demonstrate this surgery.
Indicated for nasal fold trichiasis where causing clinical issue for cornea - e.g recurrent corneal ulceration.
145
When is a Hotz-Celsus procedure indicared. Draw a diagram to demonstrate this surgery. What type of suture should be used?
Indicated for lower eyelid entropion.
6-0 polyglactin for closure of defect
146
When is a V shaped or 4 sided wedge resection indicated? How should they be closed?
Excision of eyelid masses <1/3rd eyelid margin length
Figure of 8 suture at eyelid margin - accurate eyelid margin apposition
2 layer closure - continuous suture in palpebral conjunctiva ensuring does not penetrate, simple interrupted in skin layer.
Ends of figure of 8 suture can be caught in the knot of the adjacent skin simple interrupted sutures.
Benefit of 2 layer closure = more accurate alignment and reported improved patient comfort.
147
When is lateral canthal tendonectomy indicated?
Broad skulled breeds - Mastiff, Labrador, Chow Chow, Rottweiler etc
Involuted lateral canthus due to angle traction of lateral cantal tendon - leads to lateral lower and upper eyelid entropion
Lateral canthal tendon = poorly defined musculofibrous band that connects the orbicularis oculi muscle fibres at lateral commissure to orbital ligament.
148
When is a Stades procedure indicated? Draw a diagram to show how this surgery is performed.
For correction of upper entropion/trichiasis.
149
When is Munger & Carters modification of the Kuhnt-Szymanowski procedure indicated. Draw a diagram to show how this surgery is performed.
Eyelid shortening - used to correct lower eyelid ectropion and also cases of entropion secondary to overlong eyelids
150
When is a V to Y plasty indicated? Draw a diagram to show how this surgery is performed.
Cicatricial ectropion
151
When may a modified Hotz-Celsus technique be used?
Draw a diagram of this surgery.
Brachycephalics with medial lower eyelid entropion/trichiasis
152
When is a medial canthoplasty indicated? Draw a diagram to explain this surgery.
Indicated in cases of brachycephalics with macropalpebral fissure - shortens eyelids
(Reduces palpebral fissure size and removes caruncular hairs)
Can be combined with modified Hotz-celsus and or nasal fold excision
153
When is a modified Wyman canthoplasty indicated? Draw a diagram to show how this surgery is performed.
Indicated for diamond eye conformation correction
Diamond eye = overlong upper and lower eyelids with lateral canthal weakness
154
When is a sliding lateral canthoplasty performed? Draw a diagram of this surgery. How would it be altered for a lower eyelid mass vs upper eyelid mass.
Used for removal of large tumours from eyelid (>1/3rd length)
Upper eyelid - triangle face down towards lower eyelid
Lower eyelid - triangle face up towards upper eyelid
155
When is the Mustarde technique indicated?
Draw a diagram of this surgery.
2 stage technique for removal of large upper eyelid defects (avoids trichiasis as with other techniques)
156
When may there be an indication for a third eyelid flap?
Bullous keratopathy in cats - otherwise very few indications
157
What is the Mucocutaneous Subdermal Plexus Flap (lip to lid technique used for?
Draw a diagram of this surgery.
Rotation of a graft fashioned from the upper lip that can be used to replace the lower eyelid.
Used for large lower eyelid defects.
158
What are the limitations of the third eyelid flap and why is it not commonly used?
Provides no nutrition to a compromised cornea (unlike conjunctival pedicle grafting procedures)
Limits visualisation of corneal ulcer/lesion
Contraindicated in infected corneal lesions - traps neutrophils and other white blood cells against cornea promoting keratomalacia.
159
If a third eyelid flap is placed how should it be positioned?
Either sutured to bulbar conjunctiva - benefit = allows movement with globe reducing abrasion of delicate cornea against posterior surface of the flap
OR
Suturing through stent on upper eyelid (ensuring sutures do not contact cornea by placing through superior conjunctival fornix). Benefit is that can release flap temporarily to observe cornea then re-tie the sutures as necessary.
