Download pdf - Exotic Animal Ocular Pathology Laboratory Animal Ocular ......Exotic Animal Ocular Pathology Laboratory Animal Ocular Pathology Dick Dubielzig. Vertebrate Evolution. Shark & Ray Eyes

Exotic Animal Ocular PathologyLaboratory Animal Ocular Pathology

Dick Dubielzig

Vertebrate Evolution

Shark & Ray Eyes• Cartilaginous sclera, but no bone• No muscle in the ciliary body• Smooth muscle attached to the ventral lens• Double cornea (scleral and skin) • No shading of outer segments by the retinal

pigment epithelium (RPE)

“Eye Sucking”

Sharks and RaysDouble cornea

No shading of the photoreceptorsby the RPE

Evolution of the Fishes

Higher Teleosts

• Cartilage and sometimes bone in sclera• Retractor lentis muscle (smooth muscle)

accommodation• Vascular rete called “choroidal gland”• RPE melanin has photomechanical movement• Some fish have a retinal fovea• Trichromatic vision• Double cornea (skin and scleral)• Papillary process supplies blood to the retina

Higher Teleosts

Walls. The Vertebrate Eyeand its Adaptive Radiation. 1942.

Double cornea

Choroidal gland

Round lens

Higher Teleosts

Annular ligament

Choroidal gland

Retractor lentis

Higher TeleostsFalciform process &

accommodation

Retractor lentis muscle

Walls. The Vertebrate Eye and its Adaptive Radiation. 1942.

Higher TeleostsRetinal Variations

Photomechanical Movement

Guanine in the Retinal Tapetumof the Walleye

Fish Bubble Disease (Popeye)

FishMycobacterium Granulomas

Diplostomum spathaceum

Teleost Primitive Neuroectodermal Tumor (PNET)

Fairy Basslet

Thanks to:Marie Pinkerton

Blind Cave Fish

Paraffin Block

Amphibian Eyes

Walls

Features of Amphibian Eyes

• Cartilaginous sclera, but no bone• Trichromatic vision• Photomechanical motion in the RPE• Minimal amount of accommodation with smooth

muscle• Double cornea only in the tadpole• No annular pad in lens• Retractor bulbi muscle and eyelids

Features of Amphibian EyesFrogs and Toads

Smooth Muscle

Cartilage

Cornea

BullFrog

Features of Amphibian EyesFrogs and Toads

Retina

Tadpole Eye

Cornea

AmphibianCorneal Lipidosis

Reptiles

Turtle Eyes

Annular Lens Pad

Turtle Eye

Skeletal Muscle

Lesions of Sea Turtle EyesFibropapilloma

Schistosome Eggs in the Choroid

Lizards• General features of lizard eyes

– Scleral bone and cartilage– Annular pad in lens– Skeletal muscles for accommodation– Trichromatic vision or more– Fovea– Avascular retina with special adaptations for blood supply – Special considerations by group

• Tuatara, the most primitive of the extant lizards– Lacks a conus papillaris

• Iguana, Chameleons, Monitors• Gecko

– Ecdysis– Spectacle

• Snakes are treated separately

General Features of Lizard Eyes

Walls

Features of Lizard Eyes

Conus papillaris

Features of Lizard EyesAccommodation

Chameleon Magnifying(?) Lens

Features of Lizard EyesConus Papillaris

Gecko

Ch Chameleon

Features of Lizard EyesRetina & Cornea

Iguana Shallow Fovea

Gecko Shallow Fovea

Gecko Cone-rich Retina

Cornea

Gecko Ecdysis Complications

Basilsk Lizard Corneal Epithelial Dystrophy

Chameleon Eyes

Features of Snake Eyes

• Snakes are closely related to the lizards and are thought to have lost ocular features in a degenerative process

• No cartilage or bone• No annular lens pad• Smooth muscle in iris, none in ciliary body• Vessels on the inner surface of the retina• Some snakes have a conus papillaris• Photomechanical movement in the RPE• Spectacle in front of cornea

Features of Snake Eyes

Features of Snake EyesSpectacle *Subspectacular SpaceCorneaCuticle *

Schlemm’s canalCiliary roll

Ecdysis

Transparent cuticle over the eye

Cuticle

Snake Retina

Inflammation of theSubspectacular Space

Ecdysis Failure

Surgical Drainage of the Subspectacular Space

Surgical Drainage of theSubspectacular Space

Damaged Cornea

Surgical Drainage of theSubspectacular Space

1

2

3

4

Day 1 Day 7

Day 7 Day 21

Avian Eyes

Features of Bird Eyes• Cartilage and well-developed ossicle

– Some birds have a tubular eye shape• Skeletal muscle in iris and ciliary body• Annular lens pad• Photomechanical movement in the RPE• Pecten oculi• Fovea common - some birds have two fovea• Corneal accommodation• Trichromatic vision or more

Features of Bird Eyes

Loon Eye

Ferry Bird

Avian Accommodation

Corneal accommodation

Accommodation in Diving BirdsLoons, Puffins, Penguins, Cormorants

Muscular Iris

Anterior Attachmentof Ciliary Process

The Double Fovea

Dr Jim Ver Hoeve

The temporal fovea is bilateral visionThe central fovea is used by just one eye

Pecten Oculi

Blunt Trauma

Cyclodialysis in Owl Retinal Avulsion in Hawk

Retinal Lenticular Metaplasia

Caroline Zeiss

West Nile Virus in Hawks

CataractWestern Scrub Jay

Features of Mammalian EyesMarsupials and Placental Mammals

• No bone or cartilage in sclera• No skeletal muscle• No photomechanical movement in RPE• Dichromatic vision (except Old World

primates)• No fovea (except Old World primates)• Most have blood vessels within the retina• Accommodation limited by passive action

of lens capsule on lens

Features of the Mammalian Eye

Lion Eye Rhinoceros Eye

The Nocturnal Eyefrom Walls

The Nocturnal Mammal

Springhaas

Retinal Atrophy in Albino Laboratory Rodents

Phototoxic RetinopathyNormal

Lipofuscinosis in Rescued Asiatic Black Bears

The Diurnal EyePrimate

Orangutan

Fovea

Mandrill Diabetes and Hypertension

Bilateral Optic Atrophy in Rhesus and Cynos

Normal Affected

Diurnal EyeGround Squirrel

Underwater EyeCetacean

Dolphin

Operculum

Underwater EyePinniped



Pinniped Ocular Disease

• Cataract• Lens luxation• Corneal opacity

Pinniped Ocular Disease

Cataract

Amyloid

Endothelial/Descemet’sDegeneration

Microphthalmia in Whitetail Deer Fawns

• Born blind with small, partly pigmented corneas• Come from central Wisconsin• The mother was not seen• Negative for:

– BVD titer– Hemorrhagic fever titer– Negative for heavy metals– Negative for organic chlorides– Vit A & D levels same as controls– Sites of origin indistinguishable from controls




The Tapetum Lucidum• Fibrous Tapetum: Herbivore

– Equine/Tapir/Hippo– Ruminant: not Camelid– Cetacean

• Cellular Tapetum: Carnivore– Canine type

• Mustelids• Pinniped• Bears

– Feline type• Hyena

• Fibrous Tapetum in other groups– Springhaas: Rodent

• Cellular Tapetum in other groups– Fat-tailed Lemur: Primate

• Retinal Tapetum: American Opossum

Dolphin Fibrous Tapetum

Cellular Tapetum LucidumCarnivore

Nontapetal Tapetal Tapetal

Eye Shine - Canine

Cellular Tapetum LucidumFeline

Melan-A

Autofluorescent

Fibrous Tapetum LucidumUngulates & Cetaceans

Equine

Dolphin

Impala

Tapiror

Hippo

Retinal TapetumNorth American Opossum

*

Capillary blood vessels in the ourter nuclear layer

Encephalitozoon cuniculi: Rabbit Lens Inflammatory Disease

Gram Stain Acid-fast Stain