Ophthalmology Review Flashcards

Question 1

Q

ocular anatomy (rankin)

*Extraocular Muscles**
*• Innervation**

Answer

A

Oculomotor (CN III)
- Dorsal (superior) rectus, ventral (inferior) rectus, medial rectus, and ventral (inferior) oblique muscles
Trochlear (CN IV)
- Dorsal (superior) oblique muscle
Abducens (CNVI)
- Retractor bulbi muscle, lateral rectus

Question 2

Q

ocular anatomy (rankin)

Rectus muscles

Answer

A

Dorsal (superior), ventral (inferior), medial, lateral
Rotate globe in the direction of their name
Innervated by CN III except lateral rectus CN VI

Question 3

Q

ocular anatomy (rankin)

Oblique muscles

Answer

A

Dorsal (superior) oblique muscle (CN IV) intorsion of globe
Ventral (inferior) oblique muscle (CN III) extorsion of globe

Question 4

Q

ocular anatomy (rankin)

Eyelid Muscles

Question 5

Q

ocular anatomy (rankin)

Tapetum Lucidum

Answer

A

Reflective layer in the inner choroid
Dorsal fundus
Allows second stimulation of photoreceptors
Lack tapetum
Humans, red kangaroo, squirrels, llamas, alpacas, and pigs

Question 6

Q

ocular anatomy (rankin)

Holangiotic Vascular Pattern

Answer

A

3 or 4 large retinal vessels, melanotic RPE and choroid, and a horizontally ovoid ONH

Question 7

Q

ocular anatomy (rankin)

Merangiotic Pattern

Answer

A

Vessels are confined to a broad horizontal band coincident with the area of dispersion of the myelinated nerve fibers.

Question 8

Q

ocular anatomy (rankin)

Paurangiotic

Answer

A

The retinal blood vessels are minute and restricted to the direct neighbourhood of the optic disc.

Question 9

Q

ocular anatomy (rankin)

Anangiotic

Answer

A

Retina is completely avascular, but a densely vascularised pecten oculi is attached to the linear optic nerve head and protrudes far into the inferior part of the vitreous body.

Question 10

Q

ophthalmic exam (rankin)

how far should light be

Answer

A

Bright focal light held an arm’s length distance

Question 11

Q

ophthalmic exam (rankin)

Menace Response

Answer

A

Stimulus: Motion
Receptor: Retina
Afferent: Optic nerve (II)
Efferent: Facial nerve (VII)
Effector: Orbicularis oculi
Response: Blink
Keys to remember
- Cover opposite eye
- Don’t touch facial hairs
- Learned response (~4 months+)

Question 12

Q

ophthalmic exam (rankin)

optic pathway

Question 13

Q

ophthalmic exam (rankin)

Pupillary Light Reflex (PLR)

Answer

A

Stimulus: Light
Receptor: Retina
Afferent: Optic nerve (II)
Efferent: Oculomotor (III)
Effector: Iris sphincter muscle
Response: Pupillary constriction
- Direct PLR
- Indirect or consensual PLR

“indirect left to right” = light shining in left eye

Question 14

Q

ophthalmic exam (rankin)

PLR Pathway

Answer

A

Optic nerve to chiasm
Optic tract
~20% of fibers to pretectal nuclei
Decussation (majority of fibers)
Parasympathetic nuclei of the oculormotor nerve (CN III)
Parasympathetic fibers of CN III synapse in ciliary ganglion
Short posterior ciliary nerves terminate in the iris sphincter
Constriction of stimulated eye= direct PLR
Constriction in contralateral, unstimulated eye=indirect or consensual PLR
PLR ≠ Vision
Fibers for PLR branch off optic tract before LGN
- Animals blind from cortical disease can have normal PLRs
- Eyes with negative PLRs can be visual

3 synapses: 1) pretectal nucleus, 2) edinger westphal nucleus, 3) ciliary ganglion

Question 15

Q

ophthalmic exam (rankin)

Palpebral/corneal Reflexes

Answer

A

Stimulus: Touch
Receptor: Skin/cornea
Afferent: Trigeminal nerve (V)
Efferent: Facial nerve (VII)
Effector: Orbicularis oculi
Response: Blink

Question 16

Q

ophthalmic exam (rankin)

Dazzle Reflex

Answer

A

Stimulus: Bright light
Receptor: Retina
Afferent: Optic nerve (II)
Interneuron: CNS/subcortical
Efferent: Facial nerve (VII)
Effector: Orbicularis oculi muscle
Response: Blink
Especially useful when fundus can not be visualized
- Hyphema , severe corneal disease, cataracts
No need to test if menace response is positive!!!!

only use if think they are blind!

does not involve visual cortex

Question 17

Q

ophthalmic exam (rankin)

Examination of Orbit

Answer

A

Assess orbital symmetry
- Palpation
- Globe and TEL position
- Retropulsion of globe
Oral examination
- Pytergopalatine fossa caudal to last upper molar
- Orbital disease
  - Pain on opening mouth
  - Inability to open mouth

only if think there is orbital disease

Question 18

Q

ophthalmic exam (rankin)

color of cornea → why

Question 19

Q

ophthalmic exam (rankin)

Examination of Anterior Chamber

Answer

A

should be completely black (shouldn’t notice it)

Question 20

Q

ophthalmic exam (rankin)

Posterior Segment Exam

Question 21

Q

ophthalmic exam (rankin)

Ophthalmoscopy

Question 22

Q

ophthalmic exam (rankin)

Culture and Sensitivity

Question 23

Q

ophthalmic exam (rankin)

Cytology

Question 24

Q

ophthalmic exam (rankin)

Schirmer Tear Test (STT)

Question 25

Q

ophthalmic exam (rankin)

Jones Test

Answer

A

Evaluates patency of nasolacrimal system
Apply fluorescein stain to ocular surface rinse
Hold nose down and examine nostrils
- Examine oral cavity
Normal passage < 5 min

Question 26

Q

ophthalmic exam (rankin)

Tear Film Break-Up Time

Answer

A

Tear quality assessment
Moisten strip with saline and apply to cornea
Do NOT rinse
Blink eyelids
Hold lids open and monitor for “dry spots”
Normal tear break up time >20 seconds

Question 27

Q

ophthalmic exam (rankin)

Seidel Test

Answer

A

Aqueous humor leakage
- Corneal lacerations
- Ruptured ulcers
- Surgical incisions
Apply fluorescein
Do NOT rinse
If leaking aqueous humor will create a “river”

Question 28

Q

ophthalmic exam (rankin)

Tonometry

Answer

A

Measures intraocular pressure
- Normal 15-25 mmHg
Applanation
- Tono-Pen®
Induction impact
- Tonovet ®

Question 29

Q

ophthalmic exam (rankin)

Tono-pen®

Question 30

Q

ophthalmic exam (rankin)

TonoVet®-induction-impaction

Question 31

Q

conjunctiva (rankin)

Red Eye

Answer

A

Conjunctival hyperemia
- Extensive branching
- Extraocular disease
Episcleral Injection
- Radial pattern from limbus
- Dark red
- Intraocular disease
Subconjunctival hemorrhage
- Difuse red
- Trauma/bleeding disorder

Question 32

Q

conjunctiva (rankin)

Diagnostic Tests for “Red Eye”

Answer

A

Fluorescein stain
Schirmer tear test
- don’t do for deep ulcer
Intraocular pressure
- don’t do for deep ulcer
+/- Conjunctival cytology
+/- Aerobic culture and sensitivity

Question 33

Q

conjunctiva (rankin)

Canine Conjunctivitis

Answer

A

Rarely infectious!!!!!!
Usually secondary to other abnormalities
- Entropion, ectropion, trichiasis, eyelid tumors…
- Tear film abnormalities-keratoconjunctivitis sicca (KCS)
- Irritants-chemicals, dust, smoke….
Bacteria can frequently be cultured at low numbers from NORMAL conjunctiva
- Staphylococcus , Streptococcus , Cornyebacterium , and Bacillus spp.

Question 34

Q

conjunctiva (rankin)

Treatment of Canine Conjunctivitis

Answer

A

Treat the underlying cause
Broad spectrum topical antibiotic QID
Topical corticosteroids (hydrocortisone)
- Fluorescein negative!!!
If no response to therapy
- Re-evaluate diagnosis

Question 35

Q

conjunctiva (rankin)

Follicular Conjunctivitis

Answer

A

Typically seen in young dogs
Lymphoid follicles bulbar surface of the nictitans
Etiology-immune mediated, allergic, chronic irritation….
Treatment-topical steroids +/- topical antihistamines (olopatadine)

Question 36

Q

conjunctiva (rankin)

Feline Conjunctivitis

Answer

A

Usually infectious!!!
- Do NOT use topical steroids!
- Feline herpesvirus 1 FHV-1
- Chlamydia
- Mycoplasma
- Calicivirus
Eosinophilic conjunctivitis

Question 37

Q

conjunctiva (rankin)

Feline Herpesvirus 1 FHV-1

Answer

A

Most common cause of feline conjunctivitis
- Seroprevalance up to 97% of cats
- >80% of cats that recover are carriers
- Approximately ½ of the carriers shed under normal conditions
Corneal ulcers/keratitis
Latency occurs in trigeminal ganglion
URI
Kittens most susceptible
Short lived in the environment <18hrs
Virus is inactivated by most disinfectants
Sneezing carriers the virus approximately 4 feet

DON’T USE TOPICAL STEROIDS IN CATS

Question 38

Q

conjunctiva (rankin)

FHV-1 Diagnostics

Answer

A

Clinical signs!!!!
Conjunctival cytology
- Intranuclear inclusions, PMNs
PCR - sensitive and specific
IFA - insensitive
- Fluor. stain may cause false +
Serology (serum neutralization titer) insensitive
Virus isolation
- Definitive dx for acute infection
- Insensitive for chronic infection

Question 39

Q

conjunctiva (rankin)

FHV-1

time to recover
when to treat

Answer

A

Most recover in 10-21 days
Which cases should you treat?
- Moderate to severe conjunctivitis
- Corneal disease

Question 40

Q

conjunctiva (rankin)

Treatment of FHV-1

Answer

A

Topical and systemic antiviral medications
Oral lysine
Decrease stress

Question 41

Q

conjunctiva (rankin)

Antiviral Topical Treatment

Answer

A

Cidofovir 0.5% solution
- Compounding pharmacy
- 2 times daily
Idoxuridine 0.1% solution
- Compounding pharmacy
- 4-8 times daily
Trifluridine 1% solution
- Refrigerated
- Topically irritating
- 4-8 times daily

Question 42

Q

conjunctiva (rankin)

Antiviral Systemic Treatment

Answer

A

Famciclovir
- BID
- NOT the same as valacyclovir!
Lysine
- BID
- Give with food

Question 43

Q

conjunctiva (rankin)

Antiviral Therapy for FHV-1

Answer

A

Continue therapy for at least 1 week after resolution of clinical signs

Question 44

Q

conjunctiva (rankin)

Chalmydia felis

Answer

A

URI in young cats
Chemosis usually begins unilaterally then bilateral
Follicles with chronicity

Question 45

Q

conjunctiva (rankin)

Chlamydia Diagnostics

Answer

A

Cytology
- Intracytoplasmic inclusion bodies
- Days 3-14
PCR

Question 46

Q

conjunctiva (rankin)

Chlamydia Treatment

Answer

A

Oral medication
- **Doxycycline (kittens over 4 weeks of age)
  - Esophageal stricture
- Azithromycin
- Pradofloxacin
Treat for at least a month
- Ideally at least 2 weeks beyond resolution of clinical signs
Topical medications QID
- In addition to oral therapy
- Tetracycline ( Terramycin ®)
- Erythromycin
Recurrence common
Zoonotic - rarely

Question 47

Q

conjunctiva (rankin)

Mycoplasma

Answer

A

Mycoplasma felis and M. gatae
Opportunistic
Conjunctival pseudomembranes
Diagnosis
- Cytology-small cytoplasmic basophilic inclusion bodies
- Culture in special media
- PCR test for M. felis
Pathogenicity
- Questionable
- Isolated from normal cats

Question 48

Q

conjunctiva (rankin)

Mycoplasma Treatment

Answer

A

Topical medications QID
- Tetracycline ( Terramycin ®)
- Fluoroquinolones
Oral medication
- Doxycycline (kittens over 4 weeks of age)
  - Esophageal stricture
- Pradofloxacin
Duration of therapy
- At least 2 weeks

Question 49

Q

conjunctiva (rankin)

Calicivirus

Answer

A

URI
Oral and nasal ulceration
Polyarthritis
Low pathogenicity for conjunctiva
Topical antivirals are ineffective
RNA virus
Supportive care

Question 50

Q

cornea (rankin)

Pannus

Answer

A

Chronic superficial keratitis
Most common
- German Shepherds
- Greyhounds
- Dobermans
Pigment and vascularization
- Starts laterally
Higher altitudes
Bilateral disease
NONPAINFUL!!!!!!
Atypical pannus
- Third eyelid
- Depigmented and follicles

Question 51

Q

cornea (rankin)

Pannus Treatment

Answer

A

Life long treatment!!!!
Treat aggressively initially then taper
Topical steroids
- Prednisolone acetate 1%
- Neopolydex (0.1% dexamethasone)
- 3-4 times daily
Topical cyclosporine A or tacrolimus
Taper medications
- Control with CSA or tacrolimus

Question 52

Q

cornea (rankin)

Corneal Ulcers

Clinical signs

Answer

A

Blepharospasm
Rubbing
Epiphora
Elevated third eyelid
- “Red
- Reflex uveitis
  - Miosis , aqueous flare, hypopyon, fibrin, photophobia

Question 53

Q

cornea (rankin)

Diagnosis of Corneal Ulcer

Answer

A

Examine eyelids and conjunctiva
Palpebral reflex
STT
Fluorescein staining
Examine posterior TEL
Cytology
Culture and sensitivity

Question 54

Q

cornea (rankin)

Corneal Ulcer

superficial vs deep

Answer

A

Corneal blood vessels
- 3-5 days to begin to grow
- ~1mm/day
Is it superficial or deep?

Question 55

Q

cornea (rankin)

Infected Corneal Ulcer Signs

Answer

A

Depth
Corneal malacia
Cellular infiltrate
Pain
Purulent ocular discharge
Hypopyon

Question 56

Q

cornea (rankin)

How am I going to manage the ulcer?

Answer

A

If greater than 50% depth or severe infection:
- Surgical therapy recommended: Conjunctival graft, corneoconjunctival transposition, corneal transplant, amnionic memebrane graft referral

Question 57

Q

cornea (rankin)

Surgical Therapy for Ulcers

Answer

A

Do NOT place a third eyelid flap…it only covers up the cornea and prevents you from observing the ulcer…

Question 58

Q

cornea (rankin)

Superficial NON-infected Ulcer

meds

Answer

A

Broad spectrum antibiotic
- Neomycin/bacitracin/polymyxin B ointment
  Neomycin/bacitracin/ gramacidin solution
- Tobramycin ophthalmic solution
- Treat T-QID
Mydriatic therapy
- Treat “reflex uveitis”
- Topical 1% atropine (SID or BID)
- Do not use if decreased tear production or glaucoma
Drops vs. ointment?
- Hypersalivation (especially in cats)
Analgesic/anti-inflammatory therapy
- DO NOT EVER USE TOPICAL STEROIDS OR TOPICAL NONSTEROIDAL MEDICATIONS
  - Delay corneal wound healing
  - Predispose to infection
  - Potentiate enzymatic destruction of the cornea
- Systemic NSAIDS
Analgesic therapy
- Codeine
- Tramadol
Prevent self trauma
- Elizabethan collar!!!!

Question 59

Q

cornea (rankin)

Superficial NON-infected Ulcer

after treatment?

Answer

A

Recheck in 5-7 days
If the ulcer has not healed
- Change the diagnosis…not the antibiotic!!!
If the ulcer has not resolved
- Underlying cause
- Ulcer is infected
- Indolent ulcer

Question 60

Q

cornea (rankin)

Treatment of Infected Ulcers

Answer

A

Antimicrobials - based on culture/sensitivity
Antimicrobials - based on cytology
- Cocci - cefazolin 5%,chloramphenicol
- Rods - ofloxacin, gentamicin, tobramycin
Use q 1-2 hrs initially and decrease as infection resolves
Use drops if the ulcer is deep or if perforation is a possibility…the petrolatum vehicle in ointments causes severe inflammation inside the eye
Anticollagenase agents
- Decrease stromal melting
- Serum/plasma
  - Autologous/ homogolous /heterologous
  - Treat q 1-2 hrs initially
  - Keep refrigerated for up to 2 weeks
- Others: EDTA, N-acetylcysteine , ilmostat , tetracycline antibiotics
Topical atropine1% SID or BID
Oral antibiotics
- Clavamox or enrofloxacin
Oral anti-inflammatory/analgesics
ELIZABETHAN COLLAR AND RESTRICT ACTIVITY!
Recheck in 24 hours

Question 61

Q

cornea (rankin)

Indolent Ulcer/SCCED

Answer

A

Spontaneous chronic corneal epithelial defect
BOXERS
Middle/older age dogs
Chronic
Epithelial lip
Fluorescein ‘leaking’

Question 62

Q

cornea (rankin)

Surgical Treatment of Indolent Ulcers

Answer

A

Remove loose epithelium
- Topical anesthetic
- Dilute providone-iodine soln.
- Sterile eyewash
- Debride with sterile cotton tipped applicator
- ~4 0% will heal
- Need to remove ALL loose epithelium
- Usually need to go several millimeters past fluorescein positive area
Grid / diamond burr keratotomy (NOT IN CATS)
- ~85 90% success rate

Question 63

Q

cornea (rankin)

Indolent Ulcers

meds

Answer

A

Topical broad spectrum antibiotic T QID
Topical atropine 1% (SID to BID)
Elizabethan collar
Oral analgesics/NSAIDS if needed

Question 64

Q

glaucoma (rankin)

Primary glaucoma - breed related

Answer

A

– American Cocker Spaniel
– Basset Hound
– Chow Chow
– Shar Pei
– Boston Terrier
– Fox Terrier, Wire
– Norwegian Elkhound
– Siberian Husky

(43 breeds)

Answer 55

A

– Blepharospasm
– Nictitating membrane protrusion
– Red eye
– Cloudy eye
– Mydriasis
– Decreased vision

Answer 56

A

– Red eye (episcleral injection)
– Corneal edema (blue)
– Mydriasis
– Lens subluxation/luxation
– Painful!!! (blepharospasm)
– Buphthalmia
– Retinal and optic nerve changes
– Decreased vision

Answer 57

A

Breed related
Always bilateral
“Good” eye will be lost in median of 8 months
With prophylactic therapy, median time to onset of glaucoma is 31 months

Answer 58

A

– Less than 24 hours old
– Potential for vision?

Answer 59

A

– >>24 hours old
– Buphthalmia (big, blue…..

Answer 60

A

Goals
– Save or regain, and maintain vision
– Achieve and maintain comfort
Control of intraocular pressure
– Target “safe” level
– Avoid progressive optic nerve and retinal damage with associated visual deficits

Answer 61

A

Treat aggressively if chance for vision!!!
Referral

Emergency treatment
– Topical prostaglandin analogues
Latanoprost 0.005% (Xalatan®)
Travaprost 0.004% ( Travatan ®)
– Topical carbonic anhydrase inhibitors
Dorzolamide 2% ( Trusopt ®)
Brinzolamide 1% ( Azopt ®)
– Beta blocker
Timolol 0.5 & 0.25%
Betaxolol 0.5%
Hyperosmotic agents
– Dehydrate vitreous
– Last about 6-10 hours
– IV mannitol
Dosed at 1-2 grams/kg
Administered slowly over 20 30 minutes
– Glycerin
1-2 g/kg orally
May produce emesis
– Withhold water for 4 hours
Contraindications
– Renal disease
– Cardiovascular disease
– Dehydration
– Diabetes (glycerin)
– Other debilitating disease
Ophthalmologist referral
Maintenance therapy
– Latanoprost 0.005% q12 to 24 hr
– Dorzolamide 2% q6 to 8 hr
– Timolol 0.5% q12 hr
**Treat the “normal
– Timolol 0.5% q12 hr
Frequent IOP checks for monitoring of BOTH eyes
– 1 day, 3-5 days, then weekly, monthly, q2 to 3 months

Answer 62

A

Irreversibly blind (duration >72 hours)
Buphthalmic (big, blue…blind)
– Except puppies
Absent dazzle reflex
Absent consensual PLR to fellow eye
Palliative procedure
– Enucleation
– Evisceration
– Chemical ablation

Answer 63

A

Topical prostaglandin derivatives
PGF2α derivatives
– Latanaprost 0.005% (Xalatan®)
– Travoprost 0.004% ( Travatan ®)
– Increase uveoscleral outflow
– Species specific
Causes miosis but does not lower IOP in cats
Ineffective in horses
– Used SID (in evening) or twice daily
Carbonic anhydrase inhibitors
– Dorzolamide 2% ( Trusopt ®)
– Brinzolamide 1% ( Azopt ®)
– TID to QID treatment
– Decrease aqueous humor production
– May be topically irritating
Dorzolamide pH 5.6 vs brinzolamide pH 7.5
– Oral CAI rarely used due to systemic side effects
Sympatholytic agents (adrenergic antagonists) Beta blockers
– 0.25% & 0.5% Timolol (ß1 and ß2), Betaxolol (ß1)BID
– Inhibits ß receptors on ciliary epithelium
– Decrease aqueous humor production
– May also increase aqueous humor outflow
– Mild miosis
– Potential adverse effects
Bradycardia
Exacerbation of asthma in cats
Mild decrease in tear production
Cholinergic miotics
– Direct-acting parasympathomimetic agent
▪ 2% pilocarpine
– Indirect-acting parasympathomimetic agent:
▪ 0.25% or 0.125% demecarium bromide (compounded)
– Increase aqueous humor outflow
– Usually not effective alone
– Contraindicated in uveitis and anterior lens luxation
– I do NOT recommend using topical pilocarpine (too irritating!)
– Demecarium bromide for prophylactic therapy SID
▪ Often administered with topical steroid SID

Answer 64

A

Treat the underlying problem!
– Lens luxation - refer for surgery if still visual
– Uveitis - treat the inflammation
– Intraocular neoplasia - enucleation?
– Hyphema - determine cause of hyphema

Answer 65

A

Increase aqueous humor drainage

Decrease aqueous humor production

Answer 66

A

Gonioimplants
– Tube in AC drains fluid to subconjunctival space
– Fibrosis leads to early failure
Filtering procedures:
– Creating holes in iris, sclera, ciliary body
– Low success rate in veterinary patients

Answer 67

A

Destruction of ciliary body
– Cyclophotocoagulation-diode or YAG laser
Transcleral
Endolaser
Both - postoperative pressure spike, cataract formation, inflammation
Can perform both cyclophotocoagulation and gonioimplant at the same time…increase “success” rate to 58% visual in 1 year

Answer 68

A

Corneal ulcers
– Geographic
– Dendritic
– Stromal keratitis

Answer 69

A

CLINICAL SIGNS!!!!
If it is a cat and it has a corneal ulcer….
Conjunctival cytology
- Intranuclear inclusions, neutrophils
PCR – sensitive and specific
IFA - insensitive
- Fluoroescein stain may cause false positive
Serology (serum neutralization titer) - insensitive
Virus isolation
- Definitive dx for acute infection
- Insensitive for chronic infection

Answer 70

A

Cidofovir 0.5% solution
- Compounding pharmacy
- 2 times daily
Idoxuridine 0.1% solution
- Compounding pharmacy
- 4-6 times daily
Trifluridine 1% solution
- Viroptic® and generic
- Refrigerated
- Topically irritating to most patients
Topical antibiotic- to prevent bacterial infection

Answer 71

A

Famciclovir
- 250 mg or 125 mg tablets (Famvir ®)
- 30-40 mg/kg B-TID po
Do NOT use valacyclovir
Lysine
- 250 mg po BID in kittens
- 500 mg po BID adult cats
- Give with food

Answer 72

A

Globe rupture
Symblepharon

Answer 73

A

Generally older cats (>10years)

Present with dilated pupils or vision loss

Answer 74

A

Idiopathic
– 20%
Chronic kidney disease
– 19% to 65%of cats
Hyperthyroidism
– 10% to 20%
Diabetes mellitus
Primary aldosteronism
Pheochromocytoma
Chronic anemia

Answer 75

A

Diagnostics
– Systolic blood pressure
> 160 mmHg
– CBC/chemistry panel/UA/T4
Treatment
– Treat underlying condition
– Antihypertensive medication
Amlodipine (0.18-0.22mg/kg PO SID, 0.625mg PO SID)
Goal BP < 150 mmHg
Prognosis for vision?

Answer 76

A

Acute retinal degeneration
1997 label dosing changed from 2.5mg/kg BID to 5-20mg/kg as a split or single dose
- May occur even at recommended dose (2.5mg/kg BID)
  - Especially in cats with impaired drug metabolism (renal/hepatic dz.)
  - IV administration of enrofloxacin may increase risk of retinal toxicity
In most cases the blindness is permanent
Use enrofloxacin if no other alternative
- Use only the lowest dose/shortest amount of time

Answer 77

A

Most common feline primary intraocular tumor
Malignant melanocytic neoplasm
Slow, progressive, often multifocal areas of pigmentation of the iris
Secondary glaucoma from involvement of the iridocorneal angle

Answer 78

A

Monitor for progression
– Photos or drawings in the medical record
– Recheck at 2-4 months intervals
Diode laser ablation???
Enculeation
– Thoracic radiographs
– Abdominal US

Answer 79

A

• Exophthalmos
• Enophthalmos
• Strabismus
• Elevated third eyelid
• Pain on palpation of periorbital area
• Pain on opening mouth
• Exposure keratitis

Answer 80

A

Normal sized globe displaced anteriorly/rostrally within the orbit
Due to increased orbital volume
Numerous causes
- Neoplasia, abscess/cellulitis, hemorrhage, vascular anomaly, mucocoele, cyst, myositis, etc.

Answer 81

A

proptosis (an eye that is protruding outside the orbit, usually due to trauma)

exophthalmos (an eye that is pushed forward relative to its normal position, but is still in the orbit)

buphthalmos (an enlarged, glaucomatic globe)

Answer 82

A

Normal sized globe displaced posteriorly/caudally within the orbit
Due to globe retraction, decreased orbital volume or pressure anterior to the equator of the globe
Numerous causes
- Pain, muscle wasting, loss of orbital fat, Horner’s syndrome, orbital fractures, dehydration, extraocular muscle fibrosis, adnexal neoplasia

Answer 83

A

Inflammation of the orbital tissues +/- abscess
Signalment and history
• Young animal, acute onset, compatible history (“stick chewer”)
• Possibly hyporexic or decreased chewing/aversion to hard food
Clinical signs and findings
• Exophthalmos +/- lagophthalmos
• Elevated third eyelid
• Injected conjunctival and episcleral vessels
• Resistant to retropulsion +/- painful
• Pain on periorbital palpation, yelps when mouth opened!
• Febrile

Answer 84

A

Immune-mediated inflammation targeting temporalis, masseter, and pterygoid muscles
- Type 2M myofibers
Breed predisposition:
- Golden and Labrador Retrievers
- German Shepherds
- Weimeraners
Clinical signs:
- Acute onset bilateral exophthalmos, painful and restrictive jaw movements, fever, lethargy, anorexia
Diagnosis: 2M antibody test, compatible clinical signs
Treatment: systemic immunosuppression

Answer 85

A

Origin
• Primary from any orbital tissue
• Invasion from adjacent structures
• Metastasize from distant site
Signalment and history
• Generally older patients
• Slowly progressive changes
Clinical findings
• Unilateral exophthalmos
• Elevated third eyelid
• Decreased retropulsion
• Scleral indentation on fundic exam
• Usually NOT PAINFUL

Answer 86

A

Diagnostics
- Complete physical exam
- Thoracic radiographs (met check)
- Orbital ultrasound
- CT/MRI for lesion localization and surgical planning
- FNA/biopsy of lesion
Treatment
- Orbitotomy and mass excision (Referral)
- Exenteration or radical orbitectomy
  - +/- Radiation therapy and/or chemotherapy
  - Enucleation or exenteration may also be performed as a palliative measure
- Euthanasia if advanced disease
Prognosis
- Guarded to poor
- Survival time increases with early diagnosis and surgical therapy
  - Less than 1 year in dogs, ~ 1 month in cats

Answer 87

A

Think inflammatory disease…
• If younger animal
• If painful
• If rapid onset
• If febrile
Think neoplasia…
• If older animal
• If slow onset
If bilateral…think myositis or multicentric neoplasia (lymphosarcoma)
But not all patients read the textbooks!!

Answer 88

A

Globe moves anterior and eyelids become “trapped” behind equator
- True ophthalmic emergency!!!
Caused by trauma
- HBC, dog fight, kicked by horse
- Degree of trauma needed to cause proptosis varies
  - Most common in brachycephalic dogs
    - Shallow orbit and large palpebral fissure
    - Minimal trauma needed (even exam restraint can be a cause!)
  - Prognosis very poor in horses, cats, and dolicocephalic dogs
    - Severe trauma necessary

Answer 89

A

Ocular lubricant & E-collar
- KY Jelly, artificial tears, eyewash, Vaseline, cooking oil, etc.
Complete physical exam – assess for other injuries
Complete eye exam
Decide whether to enucleate or surgically reposition eye
- 3 enucleation criteria:
  - 3 or more EOMs torn
  - Optic nerve transsected
  - Globe (cornea and/or sclera) ruptured

Answer 90

A

Globe replacement

General anesthesia
Prep
- Keep eye lubricated!
- Carefully clip eyelid hair
- Cleanse area with dilute betadine solution
  - ~1:50 dilution: 5 ml 5% betadine in 250 ml saline
  - Not betadine scrub or chlorhexidine – toxic to cornea

Answer 91

A

Medications
• Oral antibiotic
• Oral NSAID
• Topical antibiotic
• Topical atropine
• Pain meds as needed
E-collar
Keep area clean
Rechecks
• Remove sutures in 2-3 weeks
• Staged removal?

Answer 92

A

When in doubt, replace the globe
• You can always take it out, but you can never put it back!
Prognosis
• Good in general if brachycephalic and minor trauma
• Guarded for vision with intraocular hemorrhage
• Pupil size is not an indicator of prognosis
• But if direct or consensual PLR present, prognosis is good
• Vision prognosis varies (~20% have some vision)
• Better prognosis for saving globe
• Many owners value globe for cosmesis

Answer 93

A

Assess and treat the whole animal
Keep eye moist!
Rapid globe replacement if possible
When in doubt, replace the globe!

Answer 94

A

Surgical removal of globe, third eyelid & gland
+/- silicone orbital prosthesis

Answer 95

A

Removal of intraocular contents and placement of a silicone prosthesis in corneo-scleral shell
Contraindicated in cases of neoplasia/infection

Answer 96

A

Removal of globe and all orbital contents
Generally performed for orbital neoplasia

Answer 97

A

Indications: surface ocular infection or neoplasia
Suture eyelids closed
Incise skin around lids and dissect down to sclera, then work posterior

Answer 98

A

Remove globe and all orbital soft tissues
• VS. enucleation (fat/muscle left behind in orbit)
• Transpalpebral approach
• Routine skin closure
Used in cases of extensive neoplasia
Submit tissues for histopathology

Answer 99

A

Clinical signs of orbital disease:
- Exophthalmos
- Third eyelid elevation
Orbital inflammation (abscess/cellulitis) occurs in young dogs, is acute & painful, and results in fever, leukocytosis
Orbital neoplasia occurs in older dogs, is non-painful and slowly progressive
Ocular proptosis is a true ophthalmic emergency
- When in doubt, always attempt replacement with tarsorrhaphy
Enucleation involves complete removal of globe and adnexa
Evisceration is a cosmetic alternative to enucleation
Exenteration is necessary in cases of advanced orbital neoplasia

Answer 100

A

• Entropion – inversion of the eyelid margin
• Ectropion – eversion of the eyelid margin
• Combination of entropion and ectropion – “diamond eye”
– Bloodhound, Clumber Spaniel, St. Bernard, Great Dane, etc.

Answer 101

A

• Clinical signs
– Pain and squinting (blepharospasm)
– Excessive tearing (epiphora)
• Corneal sequelae
– Ulceration
– Vascularization
– Pigmentation
– Fibrosis

Answer 102

A

Anatomic entropion
- Young dogs
- Breed-related
  • Shar Peis, Retrievers, Chow Chows
Spastic entropion
- Lid spasm associated with pain (foreign body, corneal ulcer, etc.)
- Vicious cycle!
- *Evaluated by use of topical anesthetic
Cicatricial entropion
- Less common
- Associated with previous surgery, trauma, or chronic inflammation of eyelids

Answer 103

A

Eyelid tacking

– Young animals and spastic entropion
– Non-absorbable Lembert-type (interrupted) sutures
– Leave in for 3 weeks .…or longer
– Replace as necessary

Answer 104

A

• Anatomic (in mature animals)
• Hotz-Celsus procedure
– How much skin to remove??

Answer 105

A

– Normal facial hairs that contact the cornea/conjunctiva
– Ex. Entropion, Nasal folds, Medial caruncle

Answer 106

A

– Hairs emerge from Meibomian gland openings
– Sometimes cause problems

Answer 107

A

– Hairs emerge through the palpebral conjunctiva
– Very commonly cause problems (i.e., ulcers!)

Answer 108

A

Nasal fold trichiasis
– Nasal fold excision
Medial canthal trichiasis or caruncular hair
– Medial canthoplasty or local cryotherapy
Entropion
– Temporary or permanent surgical correction

Answer 109

A

en bloc excision +/- cryotherapy

Answer 110

A

Hordeolum (stye) – painful suppurative infection of eyelid glands of Zeis or Moll
Chalazion – firm, non-painful swelling of Meibomian gland caused by accumulation of lipid secretions and granulomatous reaction

Answer 111

A

More common in older animals
- Canine – ~80% of eyelid tumors are benign
*• Meibomian gland adenoma most common**
- Feline – most are malignant
*• SCC**
- Equine – SCC most common, sarcoid second
- Bovine – SCC
Therapeutic goal – destroy tumor while preserving eyelid function and cosmesis

Answer 112

A

Primary/anatomic entropion requires permanent surgical correction in adult animals
Spastic entropion should be treated with temporary correction
Entropion is the most important example of trichiasis
*– Others include nasal fold, facial hair, lacrimal caruncle**
Distichiasis and ectopic cilium represent cilia abnormalities arising from the Meibomian glands
*– Ectopic cilia are more likely to lead to corneal ulceration**
Dogs are most commonly affected by benign Meibomian gland adenomas
Eyelid tumors in cats are more often malignant (squamous cell carcinoma)

Answer 113

A

*Quantitative = KCS
– Keratoconjunctivitis sicca
– Decreased aqueous tear production
Qualitative
– Disorder of mucin or lipid tear components
– Causes tear film instability
Result in desiccation and inflammation of the ocular surface

Answer 114

A

Tear stimulation – lacrimostimulants
Tear replacement – lacrimomimetics
+/- supplemental therapy
– Secondary bacterial infections
Client education
– Must use medications as often as directed
– May take a month or more to see STT improvement
– Tear stimulant therapy is lifelong!
Parotid duct transposition surgery option

Answer 115

A

Cyclosporine A
- Optimmune® 0.2% ointment
- Compounded 1% or 2% drops or ointment
Tacrolimus
- Compounded 0.02% or 0.03% formulations
- 10-100 times more potent than CsA in vitro
T cell inhibitors with anti-inflammatory, anti-pigment, and possibly anti-fibrotic effects
Use BID for life!
Reputable compounding pharmacy is important
Cholinergic agent (Pilocarpine)
- Indicated in cases of neurogenic KCS resulting from parasympathetic denervation
- Dilute topical (0.125%, compounded) or very careful oral dosing
  - Warn owners of side effects!
    - Salivation
    - Lacrimation (desired!)
    - Urination
    - Defecation

Answer 116

A

• Tear replacements or substitutes
• Many OTC products
– Choose one with increased viscosity (not ‘rewetting drops’)
• Use 4-6 times daily+
– While tear production is decreased
– Ointments can be used before bedtime

Answer 117

A

Saliva is used to lubricate the cornea in place of tears
Recommended if medical therapy fails
• Must give adequate time for medical therapy response
Frequent small meals fed post-op to stimulate salivation
Complications possible
• Mineral deposition
• Moist dermatitis
• Sialolith/sialocele
Most still need medications post-op

Answer 118

A

Abnormality in mucin or lipid layer of tear film
Clinical signs
- Conjunctival hyperemia and dull appearance to the corneal surface
- Keratitis consisting of variable pigmentation, edema, multifocal areas of fluorescein stippling or erosions
  - With normal STT
- Marginal blepharitis, meibomianitis, chalazion
  - Both cause and clinical sign
- Corneal ulcers possible (but less likely)
- Signs may be subtle

Answer 119

A

Normal aqueous production (STT 15-25 mm/min)
Lipid deficiency
- Inspect Meibomian glands/secretions
Mucin deficiency
- **Tear film breakup time**
  - Apply fluorescein dye
  - Normal
    - >20 sec dogs
    - >17 sec cats

Answer 120

A

Clinical signs
- Mucopurulent discharge, epiphora, swelling or draining fistulas in medial canthal region
- Typically no blepharospasm, minimal conjunctival hyperemia
Usually secondary to foreign bodies but rarely find them
Treatment: repeated NL flushing, topical antibiotic + steroid solution
- May require surgery if FB is identified

Purulent discharge from lower lacrimal punctum

Answer 121

A

KCS is the most commonly diagnosed tear film abnormality in dogs
Major third eyelid abnormalities include prolapsed NM gland and scrolled cartilage
When epiphora is diagnosed, increased production vs. inadequate drainage must be determined
Dacryocystitis is an uncommon problem, generally resulting in purulent ocular discharge without blepharospasm

Answer 122

A

Treat cause if known (Specific)
In most cases the cause is not known…. (Symptommatic)

Goals of therapy

Decrease inflammation
Relieve pain
Prevent complications of uveitis

Answer 123

A

Common clinical signs of anterior uveitis:
– Aqueous flare, miosis, hypotony
Inactive posterior uveitis = chorioretinal scars (tapetal hyperreflectivity)
There are many possible causes of uveitis in small animals
– Most common diagnosis = idiopathic
Treatment goals for uveitis include decreasing inflammation, relieving pain, and preventing complications/sequelae

Answer 124

A

• Cataract = opacity in the lens or capsule
• Classification
– Etiology
– Age of onset
– Location in lens
– Stage of development
• Patient with a cataract should have a normal PLR and dazzle reflex!

Answer 125

A

The optimal stage for cataract surgery is immature (vision impairment but no LIU)
Cataracts are opacities that block light, but nuclear sclerosis is an expected aging change that causes hardening of the central lens (decreased accommodation)
Anterior lens luxation is an ophthalmic emergency
Lens subluxation and posterior luxation are often managed medically with miotics

Answer 126

A

– Bilateral – progressive loss of vision–blindness
– Decreased night vision (nyctalopia) usually first sign
– Progressive decrease in PLR
– Larger than normal resting pupil size
• Owner will sometimes report increase in “eye shine”
– Cataract formation in very late stages

Answer 127

A

• SARDS-_acute_ photoreceptor death
• Usually middle aged to older dogs; female overrepresented
• All breeds affected
• Associated clinical signs
– May have ‘Cushing’s-like’ signs for weeks or months prior to vision loss

Answer 128

A

– Acute vision loss
– Variable PLR
• Chromatic PLR
• Red light –
• Blue light +
– Fundic exam
• NORMAL initially
• Chronic cases
– Retinal degeneration

Answer 129

A

Diagnosis:
- Electroretinogram (ERG)
- May have elevated ALP, or other Cushing’s-like changes on blood work; less commonly diagnosed with Cushing’s via traditional screening tests
No proven treatment-permanent blindness
- Emphasize quality of life as blind pet

Answer 130

A

Retinal tear present which allows liquefied vitreous to enter subretinal
space
Primary ocular disorder (previous cataract surgery, inherited vitreal
degeneration, etc.)

Answer 131

A

Remains attached at ora ciliaris retinae & optic disc
Serous sub-retinal fluid-bullous retinal detachment
Exudative retinal detachments-inflammatory or exudative sub-retinal fluid
Systemic disease

Answer 132

A

• Depends on type of sub-retinal fluid/material
• Exudate (cloudy or discolored, yellow)
– Same as chorioretinitis (i.e., posterior uveitis) → suspect systemic infection
• Transudate (clear)
– A.k.a. bullous
– *Hypertension
– Hypoproteinemia
– Idiopathic (steroid responsive?)
• Dog specific

Answer 133

A

Always perform a systemic work-up in animals with non-rhegmatogenous retinal detachments
– CBC/chemistry panel/urinalysis
– Blood pressure
– Chest radiographs
– Titers/antigen tests if any suspicion of infectious cause

Answer 134

A

• Only appropriate for rhegmatogenous detachments
• Laser retinopexy
– 2 rows of burns around detachment to create adhesions
– Prophylactic vs. barrier
• Retinal reattachment

Answer 135

A

= Optic neuritis
Unilateral or bilateral
Can involve any segment of optic nerve (intraocular vs. retrobulbar)
Associated with sudden blindness, fixed and dilated pupils

Answer 136

A

• CBC, chemistry panel, urinalysis
• Titers/antigen tests for infectious organisms
• Chest radiographs
• MRI or CT scan
• CSF tap
*Think of optic neuritis as a neurologic disease!*

Answer 137

A

Referral?
Treat primary cause
Systemic steroids (immunosuppressive dose)
Oral antibiotics (empiric)
Prognosis for vision = poor

Answer 138

A

3 hallmark signs of retinal degeneration:
*– Tapetal hyperreflectivity**
*– Retinal vessel attenuation**
*– Optic disc pallor**
SARDS results in sudden blindness with a normal ophthalmic exam (ERG needed to definitively diagnose)
Rhegmatogenous retinal detachments are due to primary ocular disease
Non-rhegmatogenous retinal detachments are due to systemic disease
Optic neuritis is a neurologic disease!