Exotic animal Flashcards by Jessica Ernst

avian orbit

incomplete

very little orbital fat

poor developed extraocular muscles

orbital lacrimal gland in ventrolateral orbit

harderian gland at base of third eyelid

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Pecten

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Avian adnexa

lower eyelid mobile than upper

no meibomian glands

feathers instead of eyelashes

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Avian nictitans

very active

innervated by CN VI

movements controlled by pyrimidalis muscle

from dorsomedial orbit sweeps ventrolaterally

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Avian globe

large-outweighs brain

sclera contains cartilage & 10-18 scleral ossicles

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avian globe shapes

globose-passerines, raptors, Anterior-posterior diameter simialr to equatorial diameters

flat-aquatic birds, flattened cornea, shortened AP diameter

tubular-owls, goatsuckers, longest AP diameter

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Avian anterior segment

striated iris muscles-PLR still present but need neuromuscular blockage for mydriasis

annullar pad-accommodation, compressed by Brucke’s and Crampton’s muscle to deform lens

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Avian posterior segment

no tapetum

pecten-pigmented vascular structure, protrudes into vitreous, overlies optic nerve, nutrition

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avian retina and optic nerve

avascular retina (anagiotic)

Four retinal visual pigments-increased color spectrum including UV light

densely packed PR, thicker retina-increase visual acuity and processing

double cone with oil droplets-act as light filter to enhance color vision, reduce chromatic aberration and glare

rapid flicker fusion rate-can detect more rapid movement in more detail

Fovea-in spp with high acuity vision, high conc of PR, mono vs bi

complete decussation at optic chiasm-direct PLR only

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avian ophtho exam

menace response absent

Direct PLR only

Tonometers not validated

STT, use phenol red in smaller sp

examination without mydriasis

optic nerve most often not visible due to overlying pecten

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avian trauma clin sxs

blepharitis, eyelid lacerations

conjunctivitis, hemorrhage

ossicle fx

corneal ulceration-ant uveitis, hyphema

secondary cataract formation

penetrating injury to lens, lens (sub)luxation

choriorentitis, retinal tears or detachment

pecten avulsion

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avian trauma course of action

evaluate and stablize systemic injuries

ophtho exam

manage uveitis-topical or systemic NSAIDs

topical abx if corneal ulcer present

assess px for return to vision

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avian enucleation

traditional techniques not poss due to ossicles and large globe volume within orbit

attention to hemostasis

avoid traction on optic nerve

smaller sutures

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transaural enucleation

birds

facilitates exposure and removal of the globe

owls

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globe collapse enucleation

birds

incision and collapse of globe

eases removal from orbit

histopath-more difficult

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blepharitis and conjunctivitis in birds

most common reason for presentation in captive birds

clin sxs: blepharoedema, conjunctival hypermia, chemosis, ocular d/c, exophthalmos, corneal ulceration

everything causes this

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Course of action when bird presents with blepharitis or conjunctivitis

thorough hx, incl hsubandry and housing

conjunctival cyto, bx

conjunctival C&S

Chlamyophila PCR

skin scrapings

reptilian ocular anatomy

very similar to birds

Hardedrian gland, poorly developed extraocular muscles, +/- third eyelid

+/- NDL or puncta

eyelids-similar to birds except spectacles on snakes

reptilian globe and anterior segment

cornea and sclera-cartilage in sclera

anterior uvea-striated muscle in iris and ciliary body

lens-annular pad

reptilian posterior segment

most do not have tapetum

conus papillaris-like pecten but less developed

retina-anangiotic, cones with oil droplets, foveate

complete decussation

reptilian ophtho exam

meance response absent

direct PLR only

normal values for STT & tonometry not known

exam with mydriasis

optic nerve not visible due to overlying conus papillaris

reptilian ocular disease

usually attributes to husbandry practices

corneal ulcers common-tx similar to mammals

conjunctivits-dx an tx similar to birds

retained spectacle

dysecdesis-abnormal shedding of skin and spectable, insufficient humidity

appearance-dry, wrinkled opaque spectacle

tx: increase humidity to 50-60%, soak in water, rarely surgical removal req

pseudobuphthalmos

obstruction of nasolacrimal duct

accumulation of Harderian secretions in subspectacular space

subspectacular abscess

infection within subspectacular space and accumulation of purulent debris

obstruction of NLD

stomatitis infection create drainage

hypovitaminosis A

due to unbalanced diet squamous metaplasia of ductal epithelium and subsequent ductal occlusion clin sxs: blepharedema, conjunctivitis, narrowed palpebral fissure tx: early dz: diet change, more advanced-req vit A supplementation

fibropapilloma

green sea turtles involving eyelids and conjunctiva herpes virus? tx: sx removal +/- strontium radiation tx

Rabbit orbital anatomy

laterally laced globes venous sinus extending from globe equator to orbital apex lacrimal gland, acessory lacrimal gland, Harderian gland, third eyelid gland

Rabbit lacrimal system

ventral punctum only tortuous NLD route through lacrimal and maxillary bones areas of narrow diameter adjacent to apices of maxillary molars and incisors

rabbit retina and optic nerve

merangiotic fundus retinal vessels and myelin radiate horizontally from optic disc nearly 100% decussation of optic nerve

Rabbit ophtho exam

menace response absent Direct PLR only STT value variable PRT more useful

rabbit blepharitis

very common-differentiate from dacryocysitis causes: Pasteurella & Staph, trauma, environmental irritants, viral dx: conjunctival cyto, C&S, bx tx dictated by cause

pseudopterygium

bulbar conjunctiva grows centripetally over cornea but is nonadherent unknown cause tx: trim excessive conjunctiva, tack leading edge to conjunctival fornix, topical cyclosporine A

Dacryocystitis in rabbits

inflm of nasolacrimal sac tortuous NLD, sudden narrowing or proximity to tooth roots predisposes to obstruction dental disease, secondary bacterial inf clin sxs: conjunctivitis, purulent ocular d/c expressed from puncta dx: clin sxs, negative jone's test, skull rads/CT, C&S tx: treat dental disease, Flush NLD, systemic abx

exophthalmos in rabbits

orbital dz retrobulbar abscess due to pasteurella multocida-secondary to dental dz less common: parasitic cyst, orbital neoplasia, thymoma

retrobulbar abscess in rabbit

dx: clinical appearance, skull rads/CT, CBC-heterophilia aggressive medical management-parenteral penicillin, many need exenteration-caution with vascular plexus recurrence common

encephalitozoon cuniculi

obligate intraocular protozoa vertical transmission in utero causes neurologic dz ocular dz: iris granuloma secondary to lens capsule rupture, phacoclastic anterior uveitis, cataract dx: clin sxs, serology, PCR lens tissue tx: uveitis therapy, phacoemulsification, albendazole

ferret anatomy and exam

very similar to dogs and cats-more laterally places, retrobulbar venous sinus STT and IOP indirect ophthamoscopy

ferret conjunctivitis

common usually ocular manifestation of systemic dz-k9 distemper, Human influenza, mycobacteriosis, salmonellosis dx: clin sxs, PE, conjunctival cyto, C&S, bx, serology, PCR tx-underlying disease

ferret exophthalmos

first sign of lymphoma dx: PE, CBC, Chem, UA, Thoracic rads, Abdominal u/s