Exotic animal Flashcards
avian orbit
incomplete
very little orbital fat
poor developed extraocular muscles
orbital lacrimal gland in ventrolateral orbit
harderian gland at base of third eyelid
Pecten
Avian adnexa
lower eyelid mobile than upper
no meibomian glands
feathers instead of eyelashes
Avian nictitans
very active
innervated by CN VI
movements controlled by pyrimidalis muscle
from dorsomedial orbit sweeps ventrolaterally
Avian globe
large-outweighs brain
sclera contains cartilage & 10-18 scleral ossicles
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
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
Avian posterior segment
no tapetum
pecten-pigmented vascular structure, protrudes into vitreous, overlies optic nerve, nutrition
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
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
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
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
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
transaural enucleation
birds
facilitates exposure and removal of the globe
owls
globe collapse enucleation
birds
incision and collapse of globe
eases removal from orbit
histopath-more difficult
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
Course of action when bird presents with blepharitis or conjunctivitis
PE
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
