Module 4

Question 1

The orbit - anatomy and physiology

Answer 1

Open, dorsolateral region incomplete, orbital ligament spans laterally from zygomatic process of the frontal bone.
Zygomatic and maxillary bones - ventral orbital rim.
Frontal bone containing frontal sinus - part of dorsal orbital rim.
Medial wall - thin septum of frontal bone - susceptible to trauma, inf, neop
Optic canal (optic nerve and internal ophthalmic artery) and orbital fissure (CN III, IV, ophthalmic branch of V & VI) pass through sphenoid bone
Temporal muscle - dorsal and lateral
Masseter - medial and ventral
Intraconal - 4x rectus muscles, 2x oblique muscles, retractor bulbi, periorbital fascial sheath, CN II, III, IV, V & VI
Extraconal - zygomatic salivary gland, base of TEL, orbital fat, maxillary artery, palatine nerve, pterygopalatine nerve and ganglion
Orbital septum - anterior border, continuous with periorbital fascial sheath
Roots of maxillary 4th premolar, 1st and 2nd maxillary molar teeth are close to the orbital floor, separated only by thin alveolar bone

Question 2

Clinical signs of orbital dz

Answer 2

Signs: Exophthalmos and enophthalmos, strabismus (exotropia - laterally, esotropia - medially), resistance to retropulsion, pain on opening mouth, swelling/fistula of the pterygopalatine fossa, fundus indentation
Less specific signs: protrusion of TEL, periocular swelling, conjunctival hyperaemia, epiphora, discharge. lagophthalmos, KCS, mild inc IOP, retinal vascular changes, swollen ONH

Investigation: good clinical exam - ophthalmic and general examination. Hx. Oral examination. neuro-ophthalmic exam. Routine haematology and biochemistry, imagining.

Question 3

Oral exam

Answer 3

May be painful.
Need to differentiate orbital pain from pain from other areas.
Buccal mucosa in pterygopalatine fossa (behind last max tooth) examined for evidence of swelling, bruising or fistulous tracts.
Teeth examined should be inspected for disease
Papilla of zygomatic salivary gland duct examined, opens in mouth at level of first maxillary molar tooth.

Question 4

Ophthalmic exam

Answer 4

“pseudo-exophthalmos” - facial asymmetries or globe enlargement
Examine axial corneas from above to differentiate
Palp periorbital areas for swelling, heat or pain. Masses may be palpable in temporal fossa. Crepitus/emphysema if sinus involved.
Ausc over closed eyelids - bruit suggestive of orbital vascular abnormality
Retropulse, degree of repulsion surprisingly large in most dogs and cats, brachys are the exception. Glaucomatous eye - no resistance to retropulsion.
Strabismus - orbital space dz (displaced away from the mass) or neuro-ophthalmic causes.
Intraconal - neoplasms and inflammatory myopathies EOM, axial exophthalmos, restrictions of extraocular muscle motility.
Extraconal - non-axial exophthalmos, extraocular muscle abnormalities (periapical abscess, zygomatic sialoadenitis, masticatory myositis)

Question 5

Orbital imaging

Answer 5

Radiography - can be limited by superimposition, laterals, DVs, intraoral DV, oblique, sky-line. Dental rads. Thoracic if neoplasia suspected (take first).
US - ST exam, 10MHz transducer ideal for orbital dz, 20MHz for anterior chamber. Transcorneally - after LA, or lateral approach behind orbital ligament. Other eye - ideal normal reference. Horizontal/dorsal give good view of peri-orbital space. Colour flow Doppler and contrast-enhanced US also options
Advanced imaging - CT - bony structures, dental, sinuses etc. as well as metal, MRI - soft tissue contrast but not for metal.

Question 6

Orbital disease - congenital and developmental

Answer 6

Enophthalmos - deep orbit or microphthalmia - normal in some breeds e.g. English bull terrier, doberman. Passive TEL evident. Medial pocket syndrome.
Exophthalmos - brachycephalic, lagophthalmos - majority of blinks incomplete, exposure keratitis, axial corneal ulceration. Lubricants and medial canthoplasty to protect cornea

Question 7

Orbital disease - congenital and developmental

Answer 7

Orbital dermoid cysts - developmental choriostomas - normal tissue in abnormal location. DX: US, MRI or CT. Slow growing so may not show signs until adulthood. Care to avoid iatrogenic rupture during excision. Confirmation on histo.

Question 8

Orbital disease - congenital and developmental

Fistulas, varices

Answer 8

Orbital arteriovenous fistulas - rare congenital defect, abnormal communication between orbital arteries and veins. Pulsatile exophthalmos. Dx: colour-flow doppler US. In humans coil embolisation used but in veterinary medicine globe not usually preserved.

Varices - of orbital veins, intermittent exophthalmos and worse with exercise. Coil embolisation has been reported in the dog. If clinically significant and if coil embolisation is not possible, careful exenteration is warranted with careful planning for significant haemorrhage.

Question 9

Orbital disease - congenital and developmental

CMO

Answer 9

Craniomandibular osteopathy (canine) - 4-7months, bilateral, irregular, non-neoplastic, osseous proliferative disease of young dogs. Bones of cranium - mandible and tympanic bullae. Scotties, Cairn, Westies, +/- Airedale. Difficulty opening mouth. +/- mandibular swelling or asymmetry. Rads or CT. Cause unknown - tx is analgesia and physiotx

Question 10

Acquired. Trauma - traumatic proptosis

Answer 10

Traumatic proptosis; eyelid entrapment prevents globe returning to normal position. Emergency. Keep globe moist, antibiotic ointment can assist with this. +/- ulceration, glaucoma, hyphaema.

• Force much less for brachy cf. doliocephalic or cats (concurrent injuries more likely). Prognosis for vision 20%.
• Extraocular muscle avulsion and total hyphaema - poorer prognosis. Medial rectus first to go as shortest. Pupils not a prognostic indictor but PLR etc. better prognosis
• GA, iodine 1:50 with saline, lids pulled with Allis tissue forceps. Lateral canthotomy frequently required. Swelling –> exophthalmos so may need temporary tarsorrhaphy with left in place for 1-2 weeks. Broad spectrum antibiotics, topicals; antibiotics, lubricants, atropine.
• If prognosis for salvaging even non-functional globe is poor then enucleate.

Question 11

Acquired. Trauma - fractures

Answer 11

RTAs, high velocity blunt force traumas - tennis balls, non-accidental injuries.

• frontal, zygomatic, temporal bones.
• asymmetry, crepitus, skin lacerations, lid swelling, proptosis
• globe contusion; intraocular injury - haemorrhage, scleral rupture, lens luxation, retinal detachment
• rads can be useful, but CT supersedes. MRI - if intracranial damage. US assessing globe.
• Sinuses complicates management = open = broad spectrum antibiotics
• May involve NL duct and lead to obstructive disease
• non displaced = leave, small displaced = remove, some can be manipulated into place (closed reduction), others may need internal fixation.
• Oculocardiac reflex in zygomatic fracture - bradycardia and AV block
• optic neuropathy; initially ONH may not show abnormalities, but see retinal and ON degeneration 6-8 weeks later
• optic canal or cranium # result in CNS injury - rapid ID and stabilisation - raised ICP, brainstem injury, threat of herniation) - neuro referral.
• surgery should be performed within 5-7 days to prevent fibrosis of #s.
• sequalae: lagoph, strabismus, sensory deficits (CN V) KCS, intraocular damage (haemorrhage, glaucoma, lens luxation, cataract, retinal detachment, phthisis bulbi

Question 12

Acquired. Trauma - FB

Answer 12

Enter through conjunctiva, globe, oral cavity, facial fractures or lateral orbital ligament. Migrating FBs.
Rads - metalic FBs, CT - especially if suspected metal FB but also will pick up dense plastic, glass, bone or stone, MRI - ST contrast, good for organic FBs.
Removal may require planning/orbiotomy.

Question 13

Acquired. Trauma - zygomatic mucocoele (sialocoele)

Answer 13

Oral trauma –> excretory duct obstruction –> siaolocoele.
Secondary to zygomatic gland trauma and escape or saliva –> fibrosis.
Non-axial - extraconal. Oral examination - fluctuant swelling in the pterygopalatine fossa.
US - hypoechoic cavity. Contrast sialography. MRI.
Tx - resection with the associated gland, drainage through pterygopalatine fossa also described - can be sent for cytology

Question 14

Orbital inflammatory disease - orbital cellulitis or abscess

Answer 14

Cellulitis - inflammation along fascial planes.
Abscess - purulent discharge/material walled off.
Dental penetration, FBs, secondary to severe endophthalmitis or zygomatic salivary gland dz
Exophthalmos, eyelid swelling, axial or non-axial strabismus, pain on opening mouth, PLR defects, vision, congestion/hyperaemia
IO exam may be NAD or uveitis. Pyrexia.
Cause may not always be apparent but everything should be excluded.
Urgent tx to retain globe function, orbital infection can –> meningoencephalitis.
Us - good for assessing; hyperechoic wall surrounding hypoechoic region = abscess, cellulitis = subtle changes, distortion or obliteration of normal retrobulbar architecture.
Examine pterygopalatine fossa, caudal maxillary teeth.
MRI/CT helpful. US guided FNA –> cytology and C&S - staphs most common.
Tx: systemic ABs, NSAIDs for at least 4 weeks. Hot packs. Oral drainage of fluid - UGA, intubated and throat packed, via pterygopalatine fossa.
Depending on lagophthalmos - topical ABs and lubes may be req.
Care with severe exophthalmos that tarsorrhaphy does not result in too much tension and raised IOP.
Improvement within 1 week unless retained FB, long term sequalae = KCS and orbital structure damage

Question 15

Orbital inflammatory disease - Masticatory muscle myositis (MMM)

Answer 15

Immune mediate disorder - muscles from first branchial arch.
Inn trigeminal CN V. Type 2M myofibres.
Large breed dogs mostly but any breed, age or gender.
Bilateral, symmetrical, muscles of mastication - temporal, masseter, pterygoid. Lymphocytes and plasma cells.
CS: swelling of MM, exophthalmos, TEL protrusion. Pain on jaw opening. Anorexia. +/- pyrexia. Chronicity - enophthalmos. Acute stage may be missed. Trismus - fibrosis.
Dx: serum antibodies for 2M myofibrils, -ve if has been on steroids, or bx. Serology for T gondii or neospora
Tx - pred and tapered once CS resolve but can recrudesce. Azathioprine if poor response to pred. Supportive care - feeding, lubricating eyes, physio

Question 16

Orbital inflammatory disease - Extraocular polymyositis - EOM

Answer 16

IM of EOM. Unique myofibres, Generally - young dogs. FE. Golden retrievers. Recent stressor - spay etc.
CS: bilateral axial exophthalmos, no TEL protrusion, 360 scleral show.
Dx: CS, US - thickening and hyperechoity of EOM, also CT/MRI.
Tx: pred, recurrence common.

Question 17

Fibrosing extraocular muscle myositis with restrictive strabismus

Answer 17

sharpei

Question 17

Fibrosing extraocular muscle myositis with restrictive strabismus

Answer 17

Rare, young dogs.
Shar pei, Irish Wolfhound, Akita
enophthalmos, unilateral or bilateral strabismus ventral or ventromedial.
Bx extraocular muscles; lymphocytic-plasmacytic infiltration
Do not respond to immunosuppressive tx, sx correction of strabismus to restore vision, fibrotic muscle resected to release the globe by specialist

Question 18

Orbital neoplasia

Answer 18

Primary, secondary by local extension or mets
Dogs - primary most common, 75% malignant
Cats - secondary most common, 88% malignant
Prognosis grave. Older patients (>8) although lymphoma and MCT in the orbit in younger pts. Progressive exophthalmos.
Check LNs and for organomegaly - easier bx!
US, CT/MRI, rads, survey rads. Bx - FNA or Trucut. Invasive procedure to bx not recommended. Sx only indicated if curative or palliative via partial orbiotomy or exenteration invasive dz.
Adjunctive radiation or chemotherapy

Question 19

Orbital neoplasia - Feline restrictive orbital myofibroblastic sarcoma (FROMS)

Answer 19

Chronic, non-specific fibrosing inflammation in cats.
Poorly responsive to treatment –> euth
Middle-age to older
Unilateral, exophthalmos, progressive restriction of the globe and eyelids, exposure keratitis.
Progresses to other eye, hard palate and gingiva.
Bx thickened skin –> definitive dx.
If enucleation then must be sent with lids.
No cure. PTS

Question 20

Orbital cysts

Answer 20

Epithelial or glandular tissue - lacrimal gland (dacryops), nictitating gland, zygomatic salivary gland, retained conjunctiva post enucleation.
Paranasal sinus –> pressure necrosis –> extend into orbit
Rads, MRI/CT, cytological examination of FNA via US or CT
Surgical excision, complication.

Question 21

Loss of orbital fat or temporal muscle mass causing enophthalmos

Answer 21

Common in older dogs, also secondary to MMM
Secondary entropion possible and visual compromise from TEL protrusion
Hotz-celus +/- TEL shortening

Question 22

Globe - congenital and developmental conditions

Answer 22

Microphthalmos and anophthalmos
sporadically in many breed, or part of MODs - Dobies, Schnauzer, CKCS, Australian Shepherd, Shetland Sheepdog, Daschunds, Great Dane. (Primarily colour dilute).
Micro - TEL protrusion, may require TEL shortening
Ano - complete absence of the eye, extremely rare.

Question 23

Buphthalmos (congenital glaucoma)

Answer 23

Uni or bilateral.
Goniodysgenesis.
Buphthalmos - born with enlarged globe, dramatic in young animals, scleral elasticity
Hydrophthalmos - older

Question 24

Globe - acquired

Answer 24

Hydrophthalmos - enlargement of the globe, glaucoma, ^IOP, scleral stretches, Haabs striae (ruptures in Descemets membrane). Mid to large sized pupil and secondary lens luxation

Phthisis bulbi - end stage blind shrunken eye. Sequelae of severe ocular injury or disease, cessation of aqueous and hypotony. Likely more uncomfortable than deemed to be. Secondary entropion. Enucleate, especially cats due to post traumatic sarcoma!!

Question 25

Globe - acquired

Answer 25

Globe trauma - Dogs > cats.
Organic/stick injuries.
Cat-fight - particularly puppies 12-16 weeks prior to development of menace response
RTAs - extremities, head, neck and pelvis, most commonly injured. Mostly young cats, M>F, stray>owned, close to home generally.
Chemical injuries - flush for 30 mins
High velocity - gun-shot/air-rifle, bystander damage from hammering metal on metal
NAIs - anterior skull, young male dogs and cats, Staffies, cross-breeds and DSH.
Munchausen syndrome by proxy (MSBP) does occur but less than NAI. Real and factitious CS, deliberate injury, recovers after separation from O.

Question 26

Globe - Trauma

Classifications

Answer 26

Classifications: cause, type, structure
Assessment: Hx general and details ocular hx.
- other life threatening injuries, cover eye with damp swab
- vision, PLRs - prognostic indicator; sometimes GA or hyphaema impacts this, positive prognosis indicator if present but not guaranteed
- open vs closed
- US of globe and orbit, care to avoid intraocular contamination with gel
- look for integrity of globe, lens capsule etc, differentiate posterior vitreal detachment, vitreal membranes and retinal detachment.
- lower gain and will still see retinal detachment but vitreal disease will be eliminated
- Contrast US useful - microbubble study

Question 27

Globe - Trauma

Blunt

Answer 27

Blunt trauma

• Contusive - RTAs, ball injuries, collision with other animals and furniture
• NAIs; punching, stamping, hit with hammers, baseballs bats.
• Life threatening injuries should always be given priority
• Blunt trauma causes deformation of the cornea, subsequent equatorial expansion of the globe –> IO damage, haemorrhage, iridodialysis, iris tear, lens luxation, ciliary body dialysis, retinal schisis, retinal detachment.
• IOP rise. Scleral rupture: 360 subconjunctival hamorrhage
• Angle recession - in people and one dog - aqueous forced into iridocorneal angel, causes split in ciliary body. Gonioscopy to identify. 2nd glaucoma
• retinal tears –> vitreous gets in –> retinal detachment. Giant = >2clock hours.
• traumatic cataracts - blunt trauma week to months after, except primary lens luxation.
• haemorrhage: iris, ciliary body, choroid, retina. Vitreous takes long time to clear cf. anterior chamber.
• Optical coherence tomography helps more accurately identify/assess fundal lesions
• birds - high risk for ocular trauma, RTA/fly into windows, as above but also pecten haemorrhage can occur. Facial #s.
• People - facial #s are classed as Le Fort I (floating palate - maxilla), II (maxilla and nasal bones), and III (nasal bones, orbital walls, zygomatic).
• Optic neuropathy - shearing forces on optic nerve within optic canal.
• ON avulsion - blunt trauma
• Commotio retinae - contrecoup injuries
• Scleropteria - blast wave high velocity projectile

Question 27

Globe - Trauma

blunt

Answer 27

Blunt trauma

• Contusive - RTAs, ball injuries, collision with other animals and furniture
• NAIs; punching, stamping, hit with hammers, baseballs bats.
• Life threatening injuries should always be given priority
• Blunt trauma causes deformation of the cornea, subsequent equatorial expansion of the globe –> IO damage, haemorrhage, iridodialysis, iris tear, lens luxation, ciliary body dialysis, retinal schisis, retinal detachment.
• IOP rise. Sceral rupture: 360 subconjunctival hamorrhage
• Angle recession - in people and one dog - aqueous forced into iridocorneal angel, causes split in ciliary body. Gonioscopy to identify. 2nd glaucoma
• retinal tears –> vitreous gets in –> retinal detachment. Giant = >2clock hours.
• traumatic cataracts - blunt trauma week to months after, except primary lens luxation.
• haemorrhage: iris, ciliary body, choroid, retina. Vitreous takes long time to clear cf. anterior chamber.
• Optical coherence tomography helps more accurately identify/assess fundal lesions

Question 28

Globe trauma - Penetrating globe trauma (sharp injuries)

Answer 28

lacerations, penetrating, perforating.
Cat claws; C-shape wound, thorns/brambles.
Uveitis, endophthalmitis, panophthalmitis - sequalae
Orbital cellulitis or abscess
Bites and claws - contamination; bacterial, fungi, plant FB
Other structures can be involved.
Lens rupture = phacoclastic uveitis, if no sx –> glaucoma and phthisis bulbi. Small rents may heal and inflammation managed medically.
Young dogs eyes will stop growing after sx so try to avoid.
FBs - composition important, some toxic - siderosis bulbi from iron FBs. Also note - choice of imaging important if metal.
Extensive laceration - loss of IO contents
Penetrating injuries following dental
Thorough ophthalmic examination, US, advanced imaging CT/MRI. General exam. CN if poss but may be UGA.

Question 29

Enucleation

Answer 29

• Painful blind eye. Irretrievably damaged.
• Histo to experienced ocular pathologist.
• Transconjunctival enucleation - not when surface infection or neoplasia. -Perilimbal incision, blunt dissection along scleral plane, ID EO muscles, section, rotate medially, section retractor bulbi. CN II sectioned. Pack orbit. TEL, conj, eyelid margins then resected. Close in three layers.
• Transpalpebral - removal of the globe, lids and conj sacs in one unit. Lids are sutured together, incision around lids, blunt dissection, until posterior scleral reached, medial and canthal ligaments sectioned, muscles sectioned, medial dissection of TEL. Closure in three layers.
• NSAIDs and ABs 7 days

Question 30

Orbital prosthesis

Answer 30

Silicone sphere, placed in empty orbit, cosmetic.
12-28mm.
Prevents sinking
Complications - extrusion; infection, neoplasia or inadequate closure

Question 31

Intrascleral prosthesis

Answer 31

Perilimbal incision, evisceration leaving corneoscleral shell, implant placed
Contraindications - infection or neoplasia, corneal ulceration
Retains globe with normal motility and adnexa but reduced tear production as a result of altered corneal sensitivity.
Complications: regrowth of unidentified neoplasm, dehiscence, postoperative infections, corneal degeneration, ulceration, KCS

Question 32

Eyelids - Anatomy and physiology

Answer 32

Protect globe, distribute tears. Upper eyelid responsible for 75% of lid movement.

• eyelids; surface ectoderm, meet and fuse in utero, open 10-14 days postnatally
• tarsal plate; neural crest mesenchyme
• muscles of eyelids; mesoderm
• lids, well vascularised, contain mast cells.
• Blink CN VII –> orbicularis oculi
• Lifting the lid CN III –> levator palpebrae superioris, only striated mm supplied by CN III
• Smooth muscles (Muller’s muscle) - post-ganglionic sympathetic nerves
• Sensation CN V
• Anterior border - zeis (sebaceous), moll (sweat)
• grey line - meibomian gland openings, 20-40 per lid, produce lipid
• palpebral conjunctiva - goblet cells, produce mucous
• acinar gland - TEL 1/3 aqueous tear production
• medial canthus - upper and lower nasolacrimal punctae (2-5mm from the canthus on each lid) –> canaliculi –> lacrimal sac –> NL duct –> lacrimal bone –> opens ventrolateral floor of nasal vestibule
• Dogs - two rows of cilia upper lid, cats single row. No cilia on lower eyelids

Question 33

Congenital and developmental

Eyelids - premature opening, ophth neonatorum. dermoid

Answer 33

Premature lid opening: norm 10-14days, prem opening can result exposure keratitis, so should have lubricants applied

Ophthalmia neonatorum: infection of the conjunctival sac prior to lid opening, swollen, discharge at medial canthus, lids need to be opened. Canine and feline herpes associated with this condition. Irrigate. Topical abs and artificial tears.

Dermoid (epibulbar): choristomas, normal tissue, abnormal location, occur at lateral limbus +/- corneal involvement +/- lid involvement. Inherited: St Bernard, Birman, Burmese. Also seen: GSD, Basset, Bulldogs, Labs, Shih Tzu, DSH. Tx - sx.

Question 34

Congenital and developmental

lids - coloboma, lashes

Answer 34

Eyelid agenesis - coloboma: absence of lid tissue, dorsolateral portion. Rare in dogs, seen in cats. May present as part of MODs. Exposure keratitis, triachiasis. Sx correction.

Lash abnormalities:

• Distichiasis: dogs>cats. Emerge through or adjacent to the meibomian gland orifices. Breed-related, considered inherited. Mini dachshunds, Cocker spaniels. sometimes soft and minimal irritation but others more irritant.
• Ectopic cilia: abnormally positioned hairs, erupt through conj perpendicular to the ocular surface. Common in flat-coated retrievers, pugs, poodles. Tx = excision.

Question 35

Congenital and developmental

trichiasis, entropion

Answer 35

Trichiasis: contact of facial hair, senile entropion of cocker spaniels, excessive facial folds in brachys. Sx - stades or fold resection curative. Also seen secondary to scaring (cicatricial) - more technical procedures required.

Entropion: in-rolling of lids, discomfort and ulceration. Conformational issue. Shar pei, Bulldog, Rottweiler.

• assess lid length e.g. macropalpebral fissure syndrome (excessive length; entropion and ectropion in same lid).
• cats and brachy - medial entropion
• lateral canthal entropion; tightness of lateral canthal tendon, seen in wide skulled breeds.
• secondary to scarring, cicatricial; surgery, injury, dermatopathies.
• spastic; secondary to blepharospasm, FHV-1 corneal ulceration –> eyelid fibrosis over time. spastic entropion can complicate conformational entropion.
• intermittent entropion; cause iatrogenic in-rolling, a normal lid will correct in one blink, if not then likely has entropion
• senile entropion. brow droop. ECS and elderly cats.
• Hotz-celsus procedure effective in most cases. May be combined with lid shortening (wedge resection). +/- lateral canthal tendonotomy.

Question 36

Congenital and developmental
ectropion
macropalpebral fissure

Answer 36

Ectropion: breed-related. If mild may not require correction. Chronic conjunctivits in others, exposure related - wedge resection.

Macropalpebral fissure syndrome: longer lids than normal. Diamond eye. Ectropion or entropion-ectoprion complex. Kinks in lid. Brachys - macropalpebral fissure in conjunction with exposed globes but due exophthalmos the lids are stretched out so lagophthalmos is the main concern.

Question 37

Eyelids acquired

Answer 37

Hordeolum - “stye” in one of the marginal lid glands, external hordeolum = in zeis or moll. Internal = meibomian gland. Compresses, lance abscesses, Abs 2-4 weeks

Meibomianitis - infection/inflammation of meibomian glands “internal hordeolum”. Bulge on lid margin, yellow infiltrates seen through conj. May extrude purulent material. Compresses and Abs.

Chalazion - rupture of the meibomian glands due to trapped material in the gland e.g. meibomianitits or meibomian adenoma. Tx = curettage via conj incision, topical Abs and steroid or sx excision

Question 38

Eyelids acquired

Answer 38

Blepharitis: part of ocular disease or dermatitis.

• Staphs and their toxins –> inflammation, seen in juvenile blepharitis (puppy strangles - tx=Abs and steroid).
• Adults - staphs and streps –> pyogranulomatous swellings, tx= Abs, curettage of abscessed glands, compresses, BC.
• Parasitic blepharitis (demodex or sarcoptes)
• Fungal blepharitis (dermatophytosis)
• Immune mediated e.g. Pemphigus diseases, uveodermatological syndrome, atopy, contact allergies

Question 39

Eyelids acquired

Answer 39

Ptosis: Drooping of upper eyelid, CN III damage - levator palebae superioris, Horner’s (denervation of Muller’s muscle)

Eyelid trauma: primary wound repair important. Hair clipped, conj sac thoroughly irrigated. Good magnification important for good outcome. Figure of 8 at lid margin and 2 layer closure. 6/0 Vicryl. If loss of tissue may need blepharoplastic procedures.
-Can occur secondary to caustic or chemical injuries. Alkali reach deeper penetration and are more serious. Cicatricial entropion. Damage to glands –> tear film problems. Copious flushing for minimum 30 mins, pH testing until restored to 7.4.

Question 40

TEL - developmental

Answer 40

Scrolled cartilage: large and giant breeds mostly, also British Blue cat. Eversion or inversion. Conj incision and careful excision of scrolled portion. TEL shortening can also be necessary.

TEL gland prolapse: Bulldogs, Lhasas, Shih Tzu, etc. plus brachy cats. Gland located at the base of TEL cartilage. Associated with laxity of the cartilage to periorbita as well as overcrowding. Pocketing most common method of replacement. Care not to close ends to avoid cyst.

Question 41

TEL - acquired

Answer 41

TEL trauma: heal with minimal intervention, free margin should be repaired. Care to prevent sutures rubbing, 6/0-8/0 vicryl. FBs behind TEL common. Removal of TEL only when trauma severe and repair impossible.

TEL protrusion:
-Enophthalmos (passive with loss of retrobulbar fat), retrobulbar mass, Horner’s syndrome (also miosis, ptosis, enophthalmos), dysautonomia (bilateral unresponsive mydriasis), Cannabis intoxication, tetanus (pricked ears, risus sardonicus), Rabies (mydriasis), Tora virus (cats, last 4-8 weeks with diarrhoea and then resolves), microphthalmos (passive protrusion of TEL, may obscure vision and require shortening to allow vision)

Question 42

TEL - acquired

Answer 42

Neoplasia: primary (melanoma, adenocarcinoma, SCC, histiocytoma), secondary (lymphoma)

Inflammatory diseases of TEL:

• Plasmoma: plasma cell infiltration, IM dz, GSD, Belgian Shepherd, collies. Topical: Cyclosporine or CCS
• Nodular granulomatous episclerokeratitis (NGE): TEL, episclera, sclera and cornea. Lymphocytes, plasma cells, histiocytes, fibroblasts. Collies. CCS. Systemic txs, as well as cryo or beta-irradiation
• Idipathic sterile granulomatous disease: masses on conj, TEL, lids, skin, nasal mucosa. CS, collies, shetland sheepdogs, Austrialia kelpie. CCS or debulking sx.
• Ocular nodular fasciitis: TEL, sclear, episclera, cornea. similar to NGE and idiopathic sterile gran dz, likely spectrums of same dz.

Question 43

TEL flap sx

Answer 43

Few indications, doesn’t provide nutrition to compromised cornea.
Obscures vision.
May provide moistened environment following grafts
Will trap neuts and WBCs in melting ulcers
If placed suture to bulbar conjunctiva to allow free movement with globe and prevent abrasion.