Avian Ophthalmology in an Egg Shell
- Part 2
Anne Gemensky Metzler, DVM, MS, DACVO
Clinical Assistant Professor
The Ohio State University
Bird’s eye view …
 Pet bird diseases
 Raptor diseases
 Avian surgery
Avian Diseases - Pet Birds
Congenital Abnormalities
 Cryptophthalmus
 Continuous eyelid skin over the orbit
 Severe form: ciliary margin not visible
 Cockatoos
 100% recurrence after surgical correction
 Ectropion/exposure keratitis
 Cockatiels
Cockatiel Cryptophthalmus
Viral Infections
 Reticuloendothelial virus - orbital LSA
 Papillomavirus - proliferative blepharoconjunctivitis (African
Gray)
 Papovavirus - blepharitis (Budgie)
 Adenovirus - conjunctivitis, renal dz (lovebirds)
 Cytomegalovirus - conjunctivitis, resp. distress (Aust.
Finches)
Avian Poxvirus
 Contagious DNA virus
 Canaries & Lovebirds
 Early clinical signs:
-10-14 days
-Epiphora, blepharitis, corneal ulcers +/- perforation +/- oral dz
 Later clinical signs:
-Lid margin scabbing
-2 bact. & fungal infxn
Avian Poxvirus
 Dx: histopath--intraepithelial vesicles, epidermal hyperplasia,
intracytoplasmic inclusions
 Tx: Vit A, topical and systemic Abx, supportive
Avian Poxvirus - Sequelae
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Lid scarring/cicatrix
Secondary keratitis
Symblepharon
Uveitis
Cataract
Enophthalmus
Phthisis bulbi
Nasolacrimal obstrxn
Bacterial infections
 Chlamydial keratoconjunctivitis +/- generalized dz (parrots)
 Mycoplasma gallisepticum and spp.
-Conjunctivitis +/- upper and lower respiratory dz (House
finches, cockatiels)
- Keratoconjunctivitis (chickens)
-Tx: Topical fluoroquinolone + oral tylosin
Bacterial infections
 Staphylococcus spp.
 Blepharitis/kerato-conjunctivitis (Amazon parrots)
 Actinobacillus sp. - conjunctivitis (waterfowl)
 Mycobacterium spp. - keratitis, orbital dz, blepharitis, TEL
granuloma
Mycotic Infections
 Opportunistic fungal infections
 Secondary to trauma, ulcer, poxvirus, etc.
 Disseminated infections
 Cryptococcosis (cockatoo)
 Aspergillosis (turkeys)
 Candida albicans - keratitis, conjuctivitis (psittacines)
Protozoal Infections
 Toxoplasma gondii - blindness in canaries due to CNS
involvment
 Choroiditis, retinal detachment, optic neuritis, periorbital
myositis
Parasitic Infections - Mites
 Knemidokoptes pilae
 CS = proliferative and hyperplastic scaly lesions in periorbital area,
on beak, vent and legs
Parasitic Infections - Mites
 Predisposing Factors: Immunosuppression and genetics
 Dx: Skin scrapings
 Tx: Ivermectin (1:8 dilution in propylene glycol) @ 200 ug/kg SQ or
PO
Parasitic Infections - Nematodes
 Thelazia spp.
 Blepharospasm, conjunctivitis (parrots)
 Tx: Demecarium bromide 1 drop topically
 Oxyspirura spp.
 Conjunctivitis, chemosis, pruritis (cockatoos)
 Tx: Ivermectin topically (0.005-0.05 mg)
Parasitic Infections - Nematodes
 Oxyspirura under TEL and TEL granuloma in a seagull
Nutritional Disease - Hypovitaminosis A
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All seed diets, liver, GI or pancreatic dz
Hyperkeratosis of conjunctiva and NL duct
Swollen eyelids, epiphora
More susceptible to secondary infxns
Tx: Parenteral or oral Vit A supplements
Canary- Hypovitaminosis A
Neoplasia
 Uncommon, but any tumor type is possible
 Case reports/series:
*Eyelid - lipogranuloma, basal cell tumor
*TEL - Xanthoma (Budgie, Amazon parrot)
*Intraocular medulloepithelioma Cockatiels (1 @ OSU)
*Pituitary adenoma - Cockatiel, Budgie
*Orbital LSA - Indian Peafowl
TEL Xanthoma
 Amazon Parrot
Corneal Degeneration
 Lipid infiltrate and superficial vascularization
 Common - 8.7% of birds in one study
 Cockatiels, Budgies, parakeets, Amazon parrots, finches
Cataracts
 Senile etiology
 Macaws (esp. >35 yrs), Amazon parrot, Mynah
 Inherited
 Canaries
 Traumatic, inflammatory
 Captive/zoo waterfowl
Trauma
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Cagemates
Children
Pets
Dropped
Sinus/periocular abscesses
 Casseous inspissated material
 Must be curettaged
 Bacterial and fungal etiologies
Avian Diseases - Raptors
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Trauma
Retinal dysplasia
Eyelid agenesis
Cataracts
 Glaucoma
 Uveitis
Raptors - Ocular Trauma
 All birds with signs of bodily trauma should have a complete
ophthalmic examination
 90% of all eye lesions in raptors are traumatic in origin
Raptor Ocular Trauma
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Hyphema = #1
Eyelid lacerations
Corneal ulcers/lac’s
Fractured scleral ossicles
Iris tear/avulsion
Lens lux/capsule tear
Retinal/choroidal/
pecten tear
Retinal tears/detachments
Retinal degeneration
Glaucoma
 Usually secondary to trauma
 Most commonly seen in owls
 Only cornea can stretch due to tight fit of globe in orbit
Avian Surgery 
Principles of Avian Surgery
 Hemostasis is vital!!!!
 Small suture sizes (6-0 to 8-0)
 During enucleation, no excess traction on globe
 Can result in optic chiasm damage & contralateral blindness
 Caution with thin orbital bone, esp. orbital septum during
enucleation
Third Eyelid Laceration
 7-0 Vicryl partial thickness
Phacoemulsification
 Successfully performed in Macaws and raptors
 No intraocular lens implant available
 Traumatic cataracts not good candidates
Enucleation
 More difficult to perform due to widening of globe posterior
to limbus and tight fit of globe in orbit
 Trans-aural approach: owls, permits histology
 Globe collapsing: precludes histology
 Evisceration: precludes histology
Trans-aural enucleation
 Pluck periocular feathers
 Stay sutures to
retract lids
 Incision from anterior auricular margin to lateral canthus to expose
globe
Trans-aural enucleation
 Incise through skin down to sclera from lateral canthus to posterior
extent of globe
Trans-aural enucleation
 Skin dissected free to expose posterior globe
 360 degree conjunctival dissection
Trans-aural enucleation
 Digital pressure applied to move globe medially
 Blade creates gap between globe and orbital bone
Trans-aural enucleation
 Tenotomy scissors transect extraocular muscles and optic nerve
 Pack orbit to
control blood loss
 Gel foam
Trans-aural enucleation
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After hemostasis, remove NM and conjunctiva
Remove 2 mm strip lid margin
Recreate anterior auricular margin
Close lid margins
Trans-aural enucleation
 Appearance after completion of closure
 Use 5-0 to 7-0 absorbable suture
Globe Collapsing Enucleation
 Pluck periocular feathers
 Wire speculum to
retract eyelids
 Incision from lateral canthus extended dorsal to the anterior
auricular margin to expose globe
Globe Collapsing Enucleation
 Cornea incised 180 at dorsal limbus
 Stay suture placed to retract cornea
 360 subconjunctival dissection
Globe Collapsing Enucleation
 Region deep to auricular skin is undermined with scissors
Globe Collapsing Enucleation
 Scissors inserted between the uvea and the sclera and scleral &
scleral ossicles are severed
Globe Collapsing Enucleation
 Forceps used to grasp & collapse cut margins of sclera inward to
expose posterior orbit
 EOM & ON are severed and globe removed
Globe Collapsing Enucleation
 Hemostasis achieved via pressure, gel foam, epinephrine
 Conjunctiva, third eyelid and eyelid margins removed
 Skin closed w/ 5-0 - 7-0 absorbable suture
Evisceration
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Cornea removed
Inner contents (uvea, lens, vitreous, retina) are removed
Sclera remains in orbit
Eyelid margins removed and closed
Questions???????