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 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 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 Cagemates Children Pets Dropped Sinus/periocular abscesses Casseous inspissated material Must be curettaged Bacterial and fungal etiologies Avian Diseases - Raptors 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 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 Pluck periocular feathers Stay sutures to retract lids Incision from anterior auricular margin to lateral canthus to expose globe Incise through skin down to sclera from lateral canthus to posterior extent of globe Skin dissected free to expose posterior globe 360 degree conjunctival dissection
Digital pressure applied to move globe medially Blade creates gap between globe and orbital bone Tenotomy scissors transect extraocular muscles and optic nerve Pack orbit to control blood loss Gel foam After hemostasis, remove NM and conjunctiva Remove 2 mm strip lid margin Recreate anterior auricular margin Close lid margins Appearance after completion of closure Use 5-0 to 7-0 absorbable suture Pluck periocular feathers Wire speculum to retract eyelids Incision from lateral canthus extended dorsal to the anterior auricular margin to expose globe Cornea incised 180 at dorsal limbus Stay suture placed to retract cornea 360 subconjunctival dissection
Region deep to auricular skin is undermined with scissors Scissors inserted between the uvea and the sclera and scleral & scleral ossicles are severed Forceps used to grasp & collapse cut margins of sclera inward to expose posterior orbit EOM & ON are severed and globe removed Hemostasis achieved via pressure, gel foam, epinephrine Conjunctiva, third eyelid and eyelid margins removed Skin closed w/ 5-0 - 7-0 absorbable suture Evisceration Cornea removed Inner contents (uvea, lens, vitreous, retina) are removed Sclera remains in orbit Eyelid margins removed and closed Questions???????