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drraythe's version from 2016-04-30 17:24

Dzs of the Retina

Question Answer
What is RETINAL DYSPLASIA? What are the lesions like?Faulty differentiation of the retina (PHOTORECEPTOR CELLS), lesions are Rosettes of neuronal retinal cells & retinal folds
Diff btwn 1° & 2° retinal dysplasia?(1) Inherited
(2) Hypovitaminosis A, in-utero viral infxn
Who has idiopathic/spontaneous retinal dysplasia?Terriers, Spaniels & other breeds
What are 2 ways to get RETINITIS?Systemic infxn (E.g. Canine Distemper)
Choroidal infxn → Chorioretinitis → retinal detachment
RETINAL DEGENERATION → what is going on here?Formation of spaces w/in the retina & Loss of retinal neurons (↓ thickness of neurosensory retina “retinal atrophy”)
**What are some major reasons for retinal degeneration?Hypovitaminosis A → Night blindness (also keratin forming dz for derm)
Hypovitaminosis E → Lipid peroxidation + lipofuscin accumulation in RPE (also massive liver necrosis in liver path)
**Hypotaurine (CATS): Essential for membrane integrity → membrane degen (cats save their eyes w/ redbull?)
Toxicity (bracken fern) → Bright blindness (also czs acute cystitis)
Can be hereditary in dogs
Photoreceptor Dysplasia VS Photoreceptor Degeneration → What is the onset? What is the dz spread like?Dysplasia is EARLY onset & GENERALIZED
Degeneration is later onset & CENTRAL
How do the animals acquire Photoreceptor Dysplasia, what would you say about the receptors themselves & whats the pathogenesis?INHERITED disorder in Irish settlers, miniature/toy poodles, cocker span. Photoreceptors NEVER REACH MATURITY
Pathogenesis:
(1) Rods 1st (night blindness) + outer nuclear layer
(2) Progressive loss of inner nuclear layer (bipolar cells)
(3) Degen. Of pigment epithelium
(4) Eventual disappearance of retinal vessels → Total blindness
How does the animal get Photoreceptor Degeneration? What would you say about the receptors themselves & whats the pathogenesis?1° pigment epithelial dystrophy Collies, Labs, English Springers DEFECTIVE PHAGOCYTOSIS of photorecep. outer seg. → LIPOFUSCIN
Pathogensis:
(1) Pigmented epith. cells dark pigment patches (Macules)
(2) Lesion in center of eye = Periph. vision maintained
(3) Eventual disappearence of retinal vessels → Total blindness
How does Retinal Detachment occur? Why does it occur so easily?Separation of NEUROSENSORY RETINA (inner) from the Retinal Pigment Epithelium (RPE) (outer) (occurs easily bc ONLY attached @ optic disk & ora serrata)
Explain Congenital Retinal DetachmentNon-attachment of neurosensory retina (micropthalmia)
Explain Tractional Retinal DetachmentNeurosensory retina attached to vitreous is pulled away as vitreous shrinks (Contraction of Cyclitic Membrane)
Explain Exudative Retinal DetachmentFluid or inflammatory exudate accumulates w/in the sub-retinal space
Explain Rhegmatogenous Retinal DetachmentPeripheral neurosensory retina tears away from the ora ciliaris retinae → Leakage of liquefied vitreous thru retinal tears following trauma
What are the lesions of Retinal Detachment?Posteriorly directed ‘funnel’ attached to ora ciliaris retinae & optic disk
Separation of neurosensory retina from RPE (Retinal Pigmented Epi.)
Degeneration/necrosis of photoreceptor cells
Explain Hypovitiminosis A in young vs old animalsYOUNG: Inefficient osteogenesis
OLD: Night Blindness (photoreceptor degeneration). Need vit. A to make retinal pigment (Rhodopsin) → Poor night vision or night blindness due to photoreceptor atrophy/degen
Explain the cat eye & taurine situationTAURINE (in cats) essential for membrane integrity → membrane degeneration
Toxicity (BRACKEN FERN) → how does this affect the eye?Bright blindness → Degeneration of rods, cones, outer nuclear layers of the retina
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Dzs of the Lens

Question Answer
What is the medical term for "lens"Phakia
What is Aphakia?Complete absence of a lens
What is Microphakia?Abnormally small lens (abnormal development of the lens)
What is Spherophakia?Abnormally spherical shaped lens (abnormal development of the lens)
What is Ectopia lentis?Abnormal location of lens (abnormal development of the lens)
What is Lenticular coloboma?Absence of a portion of lens (abnormal development of the lens)
What is Lenticonus & Lentiglobus?Lenticonus: Coning of the lens, Conus may occur anteriorly or posteriorly
Lentiglobus: Localized bulging of the lens capsule & underlying cortex
What is a Congenital Cataract?Congenital opacification of the lens (inc opacity of the lens)
What is a Congenital Lens Luxation?Lens luxation as a result of a congenital dz, often 2° to Glaucoma (lens is developed normally, different than Ectopia lentis)
How do Cataracts form? What czs them?Cataracts Can be aquired or congenital. They are an inc lens OPACITY resulting from an inc hydration due to alterations in:
(1) Nutrition
(2) Metabolism
(3) Osmotic balance of lens
Congenital Cataracts form as a result of?Can be any inherited adherence of vascular structures to posterior lens capsule
Can be a result of Prenatal Dz → Ex: fetal infxns like BVD
Acquired Cataracts form as a result of?Systemic metabolic dz: DIABETES MELLITUS
Nutritional deficiencies (Amino Acids)
Ocular dz: Uveitis, Glaucoma, Retinal Degeneration, Lens Luxation, Trauma
Irradiation/Electric shock = ↑ membrane perm
Toxicity
Aging
*How does Diabetes Mellitus cz cataracts?Excessive glucose → SORBITOL sucks water into lens
What does Lens Luxation mean exactly?Dislocation of the lens
What are the 2 types of Lens Luxation?Subluxation: Partial dislocation of the lens
Luxation: Complete dislocation of the lens
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Check yo'self before you wreck yo'self

Question Answer
Ocular disorders of horses? (3)Equine keratomycosis (mycotic keratitis)
Eosinophilic keratitis
Equine recurrent uveitis
Ocular disorders of ruminants (cattle, sheep, goats)? (3)Infectious bovine keratoconjunctivitis
Bovine malignant catarrhal fever-associated uveitis
Squamous cell carcinoma
Ocular disorders of dogs? (9)Canine pannus keratitis (chronic superficial keratitis, Uberreiter’s syndrome)
Collie eye anomaly
Uveodermatologic syndrome in dogs (Vogt-Koyanagi-Harada syndrome)
Canine progressive retinal atrophy: Photoreceptor dysplasia/degeneration
Canine lymphocytic uveitis
Canine anterior uveal melanocytomas
Meibomian adenomas
Melanocytomas
Limbal melanocytomas
Ocular disorders of cats? (6)Feline herpetic keratitis
Eosinophilic keratitis
Feline infectious peritonitis-associated uveitis
Feline idiopathic lymphonodular uveitis
Feline diffuse iris melanoma
Feline primary ocular sarcoma (post-traumatic sarcoma)
***What are the malformations/lesions of COLLIE EYE ANOMALY? What are the sequale?Abnormal Choroid & Retina (bc optic cup didn't develop right) which leads to *Chorio-retinal dysplasia/hypoplasia. Sequale are retinal degeneration & detachment & intraocular hemorrhage (hyphema)
***MOST COMMON TUMOR OF CANINE EYELID IS???MEIBOMIAN GLAND ADENOMA
***What is a CONJUNCTIVAL DERMOID composed of? Sp diffs?SKIN elements (**HAIR & sweat glands) on the CONJUNCTIVA! Common in dogs (St. Bernard/Dalmatian) & cattle (Hereford)-inherited
The diff is:
(DOGS) LATERAL canthus & lateral limbus (the border of the cornea & the sclera)
(CATTLE) medial canthus, eyelid, 3rd eyelid
***BACTERIA which infect the conjunctiva?*IBK “pink eye” Moraxella bovis**
Mycoplasma felis/gatae
Chlamydia psittaci
***How is it that the ULCER of ULCERATIVE KERATITIS forms?Proteases/collagenases liquefy corneal stroma (keratomalacia) → ULCER
**"Melting ulcer" of the cornea is called?SUPPURATIVE KERATOMALACIA
(Sequale of Moraxella bovis infxn)
***Keratitis punctata → WHAT IS THIS?Clumps of inflammatory cells to posterior of cornea (this is under "anterior uveitis") (will see “Mutton-fat” keratic precipitates = White/yellow greasy precipitates of inflammatory cells (granulomatous response) adhere to corneal epithelium)
**Aqueous flare → WHAT IS GOING ON HERE? What are the sequale?Exudate (inflammatory cells/fibrin) in aqueous, which is altered formation of aqueous → ↓ intraocular pressure
**What is Hypopyon?Yellow/white/pink floccular sediment in the anterior chamber
***WHAT IS Hyphema??Settlement of RBCs (blood) in anterior chamber
***WHAT IS ANTERIOR SYNECHIA? POSTERIOR SYNECHIA?ANT = Adhesion of iris or cornea

POST = Adhesion of iris to lens
*Iris bombe IS WHAT?Complete posterior synechia (360°) Blocks papillary aqueous flow → ↑ posterior chamber pressure. The iris may then bow forward & also attach to the cornea
**What are the lesions youd see in Posterior Uveitis/Choroiditis?Marked exudation (choroid / vitreous)
Retinal degeneration/detachment
Atrophy/proliferation of choroidal pigment cells
**What are some major reasons for retinal degeneration?Hypovitaminosis A → Night blindness (also keratin forming dz for derm)
Hypovitaminosis E → Lipid peroxidation + lipofuscin accumulation in RPE (also massive liver necrosis in liver path)
**Hypotaurine (CATS): Essential for membrane integrity → membrane degen (cats save their eyes w/ redbull?)
Toxicity (bracken fern) → Bright blindness (also czs acute cystitis)
Can be hereditary in dogs
*How does Diabetes Mellitus cz cataracts?Excessive glucose → SORBITOL sucks water into lens
*List 4 causes of retinal degeneration(1) Retinitis
(2) Glaucoma
(3) Choroiditis
(4) Vitamin A def
*Collie Eye Anomaly is an?Inherited defect characterized by chorioretinal dysplasia
*T or F. Iridocyclitis may result in glaucoma?True
*T or F. Progressive retinal atrophy in dogs is inherited?True
*T or F. Hypopyon is the presence of neutrophils and fibrin in the anterior chamber?True
*T or F. KCS results in decreased lacrimal secretion?True
*T or F. An external hordeolum is a supurative adenitis of the Meibomian gland?False. An INTERNAL hordeolum is usppurative adenitis of the Meibomian gland
*T or F. Suppurative adenitis of the glands of Mol or Zeis is an internal hordeolum?False. Is an EXTERNAL hordeolum
*In horses, periodic opthalmia is synonymous w/?Recurrent uveitis
*Which tumor are Hereford cows most prone to? What might it look like?SCC. A white plaque on the cornea
*What is Keratomalacia & when would we see it?It is a soft cornea/melting ulcer. We see it during ulcerative keratitis when proteases/collagenases liquefy the corneal stroma
*List 5 lesions assoc. w/ Anterior Uveitis(1) Keratitis punctata (Clumps of inflammatory cells posterior to the cornea)
(2) Aqueous flare
(3) Glaucoma
(4) Hypopyon
(5) Hyphema
*What is the MAIN pathogenesis of cataracts?Sorbitol accumulates due to DM and osmotically attracts water
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