Ophthalmology Review Flashcards
ocular anatomy (rankin)
- *Extraocular Muscles**
- *• Innervation**
- 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
ocular anatomy (rankin)
Rectus muscles
Dorsal (superior), ventral (inferior), medial, lateral
Rotate globe in the direction of their name
Innervated by CN III except lateral rectus CN VI
ocular anatomy (rankin)
Oblique muscles
- Dorsal (superior) oblique muscle (CN IV) intorsion of globe
- Ventral (inferior) oblique muscle (CN III) extorsion of globe
ocular anatomy (rankin)
Eyelid Muscles
ocular anatomy (rankin)
Tapetum Lucidum
- Reflective layer in the inner choroid
- Dorsal fundus
- Allows second stimulation of photoreceptors
- Lack tapetum
- Humans, red kangaroo, squirrels, llamas, alpacas, and pigs
ocular anatomy (rankin)
Holangiotic Vascular Pattern
3 or 4 large retinal vessels, melanotic RPE and choroid, and a horizontally ovoid ONH
ocular anatomy (rankin)
Merangiotic Pattern
Vessels are confined to a broad horizontal band coincident with the area of dispersion of the myelinated nerve fibers.
ocular anatomy (rankin)
Paurangiotic
The retinal blood vessels are minute and restricted to the direct neighbourhood of the optic disc.
ocular anatomy (rankin)
Anangiotic
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.
ophthalmic exam (rankin)
how far should light be
Bright focal light held an arm’s length distance
ophthalmic exam (rankin)
Menace Response
- 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+)
ophthalmic exam (rankin)
optic pathway
ophthalmic exam (rankin)
Pupillary Light Reflex (PLR)
- 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
ophthalmic exam (rankin)
PLR Pathway
- 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
ophthalmic exam (rankin)
Palpebral/corneal Reflexes
- Stimulus: Touch
- Receptor: Skin/cornea
- Afferent: Trigeminal nerve (V)
- Efferent: Facial nerve (VII)
- Effector: Orbicularis oculi
- Response: Blink
ophthalmic exam (rankin)
Dazzle Reflex
- 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
ophthalmic exam (rankin)
Examination of Orbit
- 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
ophthalmic exam (rankin)
color of cornea → why
ophthalmic exam (rankin)
Examination of Anterior Chamber
should be completely black (shouldn’t notice it)
ophthalmic exam (rankin)
Posterior Segment Exam
ophthalmic exam (rankin)
Ophthalmoscopy
ophthalmic exam (rankin)
Culture and Sensitivity
ophthalmic exam (rankin)
Cytology
ophthalmic exam (rankin)
Schirmer Tear Test (STT)
ophthalmic exam (rankin)
Jones Test
- 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
ophthalmic exam (rankin)
Tear Film Break-Up Time
- 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
ophthalmic exam (rankin)
Seidel Test
- Aqueous humor leakage
- Corneal lacerations
- Ruptured ulcers
- Surgical incisions
- Apply fluorescein
- Do NOT rinse
- If leaking aqueous humor will create a “river”
ophthalmic exam (rankin)
Tonometry
- Measures intraocular pressure
- Normal 15-25 mmHg
- Applanation
- Tono-Pen®
- Induction impact
- Tonovet ®
ophthalmic exam (rankin)
Tono-pen®
ophthalmic exam (rankin)
TonoVet®-induction-impaction
conjunctiva (rankin)
Red Eye
- Conjunctival hyperemia
- Extensive branching
- Extraocular disease
- Episcleral Injection
- Radial pattern from limbus
- Dark red
- Intraocular disease
- Subconjunctival hemorrhage
- Difuse red
- Trauma/bleeding disorder
conjunctiva (rankin)
Diagnostic Tests for “Red Eye”
- 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
conjunctiva (rankin)
Canine Conjunctivitis
- 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.
conjunctiva (rankin)
Treatment of Canine Conjunctivitis
- Treat the underlying cause
- Broad spectrum topical antibiotic QID
- Topical corticosteroids (hydrocortisone)
- Fluorescein negative!!!
- If no response to therapy
- Re-evaluate diagnosis
conjunctiva (rankin)
Follicular Conjunctivitis
- Typically seen in young dogs
- Lymphoid follicles bulbar surface of the nictitans
- Etiology-immune mediated, allergic, chronic irritation….
- Treatment-topical steroids +/- topical antihistamines (olopatadine)
conjunctiva (rankin)
Feline Conjunctivitis
- Usually infectious!!!
- Do NOT use topical steroids!
- Feline herpesvirus 1 FHV-1
- Chlamydia
- Mycoplasma
- Calicivirus
- Eosinophilic conjunctivitis
conjunctiva (rankin)
Feline Herpesvirus 1 FHV-1
- 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
conjunctiva (rankin)
FHV-1 Diagnostics
- 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
conjunctiva (rankin)
FHV-1
- time to recover
- when to treat
- Most recover in 10-21 days
- Which cases should you treat?
- Moderate to severe conjunctivitis
- Corneal disease
conjunctiva (rankin)
Treatment of FHV-1
- Topical and systemic antiviral medications
- Oral lysine
- Decrease stress
conjunctiva (rankin)
Antiviral Topical Treatment
- 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
conjunctiva (rankin)
Antiviral Systemic Treatment
- Famciclovir
- BID
- NOT the same as valacyclovir!
- Lysine
- BID
- Give with food
conjunctiva (rankin)
Antiviral Therapy for FHV-1
Continue therapy for at least 1 week after resolution of clinical signs
conjunctiva (rankin)
Chalmydia felis
- URI in young cats
- Chemosis usually begins unilaterally then bilateral
- Follicles with chronicity
conjunctiva (rankin)
Chlamydia Diagnostics
- Cytology
- Intracytoplasmic inclusion bodies
- Days 3-14
- PCR
conjunctiva (rankin)
Chlamydia Treatment
- Oral medication
- **Doxycycline (kittens over 4 weeks of age)
- Esophageal stricture
- Azithromycin
- Pradofloxacin
- **Doxycycline (kittens over 4 weeks of age)
- 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
conjunctiva (rankin)
Mycoplasma
- 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
conjunctiva (rankin)
Mycoplasma Treatment
- Topical medications QID
- Tetracycline ( Terramycin ®)
- Fluoroquinolones
- Oral medication
- Doxycycline (kittens over 4 weeks of age)
- Esophageal stricture
- Pradofloxacin
- Doxycycline (kittens over 4 weeks of age)
- Duration of therapy
- At least 2 weeks
conjunctiva (rankin)
Calicivirus
- URI
- Oral and nasal ulceration
- Polyarthritis
- Low pathogenicity for conjunctiva
- Topical antivirals are ineffective
- RNA virus
- Supportive care
cornea (rankin)
Pannus
- 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
cornea (rankin)
Pannus Treatment
- 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
cornea (rankin)
Corneal Ulcers
- Clinical signs
- Blepharospasm
- Rubbing
- Epiphora
- Elevated third eyelid
- “Red
- Reflex uveitis
- Miosis , aqueous flare, hypopyon, fibrin, photophobia
cornea (rankin)
Diagnosis of Corneal Ulcer
- Examine eyelids and conjunctiva
- Palpebral reflex
- STT
- Fluorescein staining
- Examine posterior TEL
- Cytology
- Culture and sensitivity
cornea (rankin)
Corneal Ulcer
- superficial vs deep
- Corneal blood vessels
- 3-5 days to begin to grow
- ~1mm/day
- Is it superficial or deep?
cornea (rankin)
Infected Corneal Ulcer Signs
- Depth
- Corneal malacia
- Cellular infiltrate
- Pain
- Purulent ocular discharge
- Hypopyon
cornea (rankin)
How am I going to manage the ulcer?
- If greater than 50% depth or severe infection:
- Surgical therapy recommended: Conjunctival graft, corneoconjunctival transposition, corneal transplant, amnionic memebrane graft referral
cornea (rankin)
Surgical Therapy for Ulcers
Do NOT place a third eyelid flap…it only covers up the cornea and prevents you from observing the ulcer…
cornea (rankin)
Superficial NON-infected Ulcer
- meds
- Broad spectrum antibiotic
- Neomycin/bacitracin/polymyxin B ointment
Neomycin/bacitracin/ gramacidin solution - Tobramycin ophthalmic solution
- Treat T-QID
- Neomycin/bacitracin/polymyxin B ointment
- 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
- DO NOT EVER USE TOPICAL STEROIDS OR TOPICAL NONSTEROIDAL MEDICATIONS
- Analgesic therapy
- Codeine
- Tramadol
- Prevent self trauma
- Elizabethan collar!!!!
cornea (rankin)
Superficial NON-infected Ulcer
- after treatment?
- 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
cornea (rankin)
Treatment of Infected Ulcers
- 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
cornea (rankin)
Indolent Ulcer/SCCED
- Spontaneous chronic corneal epithelial defect
- BOXERS
- Middle/older age dogs
- Chronic
- Epithelial lip
- Fluorescein ‘leaking’
cornea (rankin)
Surgical Treatment of Indolent Ulcers
-
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
cornea (rankin)
Indolent Ulcers
- meds
- Topical broad spectrum antibiotic T QID
- Topical atropine 1% (SID to BID)
- Elizabethan collar
- Oral analgesics/NSAIDS if needed
glaucoma (rankin)
Primary glaucoma - breed related
– American Cocker Spaniel
– Basset Hound
– Chow Chow
– Shar Pei
– Boston Terrier
– Fox Terrier, Wire
– Norwegian Elkhound
– Siberian Husky
(43 breeds)
glaucoma (rankin)
Owner may report:
– Blepharospasm
– Nictitating membrane protrusion
– Red eye
– Cloudy eye
– Mydriasis
– Decreased vision
glaucoma (rankin)
Clinical Signs of Glaucoma
- Ophthalmic findings
– Red eye (episcleral injection)
– Corneal edema (blue)
– Mydriasis
– Lens subluxation/luxation
– Painful!!! (blepharospasm)
– Buphthalmia
– Retinal and optic nerve changes
– Decreased vision
glaucoma (rankin)
Primary Glaucoma
- 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
glaucoma (rankin)
Secondary Glaucoma Signs/Causes
glaucoma (rankin)
- *Acute vs. Chronic?**
- *▪ Acute**
– Less than 24 hours old
– Potential for vision?
glaucoma (rankin)
- *Acute vs. Chronic?**
- *• Chronic**
– >>24 hours old
– Buphthalmia (big, blue…..
glaucoma (rankin)
Glaucoma Therapy
- goals
- control of intraocular pressure
- 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
glaucoma (rankin)
Therapy for Acute Glaucoma
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
glaucoma (rankin)
Chronic Glaucoma
- signs
- treatment
- 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
glaucoma (rankin)
Glaucoma Medications
- 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
glaucoma (rankin)
Therapy for Secondary Glaucoma
Treat the underlying problem!
– Lens luxation - refer for surgery if still visual
– Uveitis - treat the inflammation
– Intraocular neoplasia - enucleation?
– Hyphema - determine cause of hyphema
glaucoma (rankin)
Surgical Therapy for Glaucoma
- goals
Increase aqueous humor drainage
Decrease aqueous humor production
glaucoma (rankin)
Surgical Therapy - Increase Outflow
- 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
glaucoma (rankin)
Surgical Therapy Decrease Production
- 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
feline ophthalmology (rankin)
Feline Herpesvirus 1
- cause what in eyes
Corneal ulcers
– Geographic
– Dendritic
– Stromal keratitis
feline ophthalmology (rankin)
Diagnosis of FHV-1
- 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
feline ophthalmology (rankin)
Feline Herpesvirus Topical Treatment
- 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
feline ophthalmology (rankin)
Complications of FHV-1
- Globe rupture
- Symblepharon
feline ophthalmology (rankin)
Systemic Hypertension
Generally older cats (>10years)
Present with dilated pupils or vision loss
feline ophthalmology (rankin)
Hypertensive Retinopathy
- signs
feline ophthalmology (rankin)
Hypertensive Retinopathy
- etiology
- Idiopathic
– 20% - Chronic kidney disease
– 19% to 65%of cats - Hyperthyroidism
– 10% to 20% - Diabetes mellitus
- Primary aldosteronism
- Pheochromocytoma
- Chronic anemia
feline ophthalmology (rankin)
Hypertensive Retinopathy
- diagnostics
- treatment
- 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?
feline ophthalmology (rankin)
Diffuse Iris Melanoma
- 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
feline ophthalmology (rankin)
Distinguish DIM from Iris Nevus
feline ophthalmology (rankin)
Diffuse Iris Melanoma
- prognosis
feline ophthalmology (rankin)
Treatment Options for DIM
- Monitor for progression
– Photos or drawings in the medical record
– Recheck at 2-4 months intervals - Diode laser ablation???
- Enculeation
– Thoracic radiographs
– Abdominal US
the orbit (meekins)
Exophthalmos
- 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.
the orbit (meekins)
Important to differentiate exophthalmos from:
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)
the orbit (meekins)
Important to differentiate enophthalmos from:
the orbit (meekins)
Skull Radiographs
the orbit (meekins)
Ultrasound
the orbit (meekins)
Computed Tomography (CT)
the orbit (meekins)
Magnetic Resonance Imaging (MRI)
the orbit (meekins)
Orbital Cellulitis/Abscess
- what
- signalment and history
- clinical signs
- exam
- 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
the orbit (meekins)
Orbital Neoplasia
- origin
- signalment and history
- clinical findings
- 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
the orbit (meekins)
Ocular Proptosis
- what
- caused by…
- 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
- Most common in brachycephalic dogs
the orbit (meekins)
Ocular Proptosis Treatment
- surgical?
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
the orbit (meekins)
Orbital Surgery
- Enucleation (what)
- Surgical removal of globe, third eyelid & gland
- +/- silicone orbital prosthesis
the orbit (meekins)
Orbital Surgery
• Evisceration (what)
- Removal of intraocular contents and placement of a silicone prosthesis in corneo-scleral shell
- Contraindicated in cases of neoplasia/infection
the orbit (meekins)
Orbital Surgery
• Exenteration (what)
- Removal of globe and all orbital contents
- Generally performed for orbital neoplasia
the orbit (meekins)
Transpalpebral Enucleation
- Indications: surface ocular infection or neoplasia
- Suture eyelids closed
- Incise skin around lids and dissect down to sclera, then work posterior
the orbit (meekins)
Evisceration
- technique
- indication
diseases of the eyelids (meekins)
Entropion vs Ectropion
• 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.
diseases of the eyelids (meekins)
Entropion
- clinical signs
- sequelae
• Clinical signs
– Pain and squinting (blepharospasm)
– Excessive tearing (epiphora)
• Corneal sequelae
– Ulceration
– Vascularization
– Pigmentation
– Fibrosis
diseases of the eyelids (meekins)
Entropion (Types)
-
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
diseases of the eyelids (meekins)
Temporary Entropion Correction
Eyelid tacking
– Young animals and spastic entropion
– Non-absorbable Lembert-type (interrupted) sutures
– Leave in for 3 weeks .…or longer
– Replace as necessary
diseases of the eyelids (meekins)
Permanent Entropion Correction
• Anatomic (in mature animals)
• Hotz-Celsus procedure
– How much skin to remove??
diseases of the eyelids (meekins)
Trichiasis
– Normal facial hairs that contact the cornea/conjunctiva
– Ex. Entropion, Nasal folds, Medial caruncle
diseases of the eyelids (meekins)
Distichiasis
– Hairs emerge from Meibomian gland openings
– Sometimes cause problems
diseases of the eyelids (meekins)
Ectopic cilia
– Hairs emerge through the palpebral conjunctiva
– Very commonly cause problems (i.e., ulcers!)
diseases of the eyelids (meekins)
Distichiasis Treatment
diseases of the eyelids (meekins)
Ectopic Cilia
- Treatment
en bloc excision +/- cryotherapy
diseases of the eyelids (meekins)
Inflammatory Diseases
- Hordeolum
- Chalazion
- 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
diseases of the eyelids (meekins)
Eyelid Neoplasia
- 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
diseases of the eyelids (meekins)
Eyelid Neoplasia
- Treatment: Debulk and Cryotherapy
diseases of the eyelids (meekins)
Eyelid Neoplasia
- Treatment: Excision
diseases of the eyelids (meekins)
Eyelid Neoplasia
- treatment
- when is benign neglect ok?
- what if malignant
lacrimal system and nictitating membrane (meekins)
Keratoconjunctivitis Sicca (KCS)
- what
- who
lacrimal system and nictitating membrane (meekins)
Keratoconjunctivitis Sicca (KCS)
- Clinical Signs
lacrimal system and nictitating membrane (meekins)
KCS Causes
lacrimal system and nictitating membrane (meekins)
KCS Causes
• Neurologic dysfunction
lacrimal system and nictitating membrane (meekins)
Diagnosis of KCS
lacrimal system and nictitating membrane (meekins)
Surgical Treatment
• Parotid duct transposition (PDT)
- 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
lacrimal system and nictitating membrane (meekins)
Qualitative Tear Deficiency
• Diagnosis
- 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
- **Tear film breakup time**
lacrimal system and nictitating membrane (meekins)
Qualitative Tear Deficiency Treatment
- lipid
- mucin
lacrimal system and nictitating membrane (meekins)
Nictitating Membrane
- what
- properties
lacrimal system and nictitating membrane (meekins)
Causes: Third Eyelid Elevation
lacrimal system and nictitating membrane (meekins)
Prolapsed Gland of the Third Eyelid
- common name?
- who?
lacrimal system and nictitating membrane (meekins)
Prolapsed Gland Treatment:
lacrimal system and nictitating membrane (meekins)
“Scrolled” Third Eyelid Cartilage
lacrimal system and nictitating membrane (meekins)
Nictitans Neoplasia
lacrimal system and nictitating membrane (meekins)
Epiphora
- what
- causes
lacrimal system and nictitating membrane (meekins)
Epiphora Diagnostic Tests
uvea (meekins)
Uveitis terminology
• Anterior uveitis
• Posterior uveitis
• Panuveitis
• Endophthalmitis
• Panophthalmitis
uvea (meekins)
Anterior Uveal Tract
uvea (meekins)
Signs of Anterior Uveitis
uvea (meekins)
Posterior Uveal Tract
uvea (meekins)
Signs of ACTIVE Posterior Uveitis
uvea (meekins)
Signs of INACTIVE Posterior Uveitis
uvea (meekins)
- *Causes of uveitis:**
- *ocular manifestations of systemic dz**
uvea (meekins)
- *Causes of uveitis:**
- *primary ocular**
uvea (meekins)
Anti-inflammatory Therapy
uvea (meekins)
Treatment of Uveitis
- systemic immunosuppresives
- antimicrobials
uvea (meekins)
- *Treatment of Uveitis**
- *• Mydriatic/cycloplegic**
lens and vitreous (meekins)
Lens Anatomy
lens and vitreous (meekins)
Lens Physiology
lens and vitreous (meekins)
Nuclear Sclerosis
lens and vitreous (meekins)
Cataract Etiology
lens and vitreous (meekins)
Cataract Age of Onset
lens and vitreous (meekins)
Cataract Location
lens and vitreous (meekins)
Cataract Stage
lens and vitreous (meekins)
Cataract Medical Therapy
lens and vitreous (meekins)
Cataract Surgery
lens and vitreous (meekins)
Cataract Surgery Work-Up
lens and vitreous (meekins)
Cataract Surgery Complications
lens and vitreous (meekins)
Anterior Lens Luxation Treatment
lens and vitreous (meekins)
is lens luxation an emergency?
lens and vitreous (meekins)
Lens Luxation Management
- primary lens subluxation
- posterior lens luxation
retina and optic nerve (meekins)
Sudden Acquired Retinal Degeneration Syndrome
• Clinical signs:
– Acute vision loss
– Variable PLR
• Chromatic PLR
• Red light –
• Blue light +
– Fundic exam
• NORMAL initially
• Chronic cases
– Retinal degeneration
retina and optic nerve (meekins)
Retinal Detachments
small vs large
retina and optic nerve (meekins)
Rhegmatogenous retinal detachment
-
Retinal tear present which allows liquefied vitreous to enter subretinal
space - Primary ocular disorder (previous cataract surgery, inherited vitreal
degeneration, etc.)
retina and optic nerve (meekins)
Non-rhegmatogenous retinal detachment
- 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
retina and optic nerve (meekins)
Differentials for Non-rhegmatogeous RD
• 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
retina and optic nerve (meekins)
Surgical Repair of Retinal Detachments
• Only appropriate for rhegmatogenous detachments
• Laser retinopexy
– 2 rows of burns around detachment to create adhesions
– Prophylactic vs. barrier
• Retinal reattachment
retina and optic nerve (meekins)
Optic Neuritis
retina and optic nerve (meekins)
DDX Optic Neuritis
