Most often in cats

Brown/black foci occurs

All of the above:

UV

Hypovitamin E

Taurine deficiency

Enrofloxin in cats

Which of these congenital defects does not have to be present at birth?

1. An optically transparent window

2. A way to focus light

3. Controls the amount of light admitted

4. An array of photoreceptors

5. A computer to appreciate the outside world

1. Neuroectoderm

2. Ectoderm

3. Neural crest mesenchyme

4. Mesodermal blood vessels

1. Outpocketing of the brain --> optic cup arises from sustained neuroectodermal proliferation at point where it touches the ectoderm

2. A double-layered cup forms:

Inner layer --> neural retina

Outer layer --> retinal pigment epithelium

3. Lens placode forms by proliferation of ectoderm in contact w/neuroectoderm until it forms a vesicle

4. Asymmetric optic cup invagination produces an inferior choroidal fissure at the bottom of the eye

Blood vessels entering the back of the eye (Hyaloid Artery) fuse w/vessels entering from the front of the eye to form the tunica vasculosa lentis.

This involutes at the end of development

1. Genetic defects

2. Teratogens (viral, toxic, irradiation, hyperthermia)

3. Nutritional imbalances

4. Toxicoses

5. Physical trauma

1. Defective organogenesis

2. Defects of a specific segment

i.e. - surface ectoderm, anterior/posterior segment mesenchyme abnormalities, neuroectodermal maldevelopment

TRUE - varies in severity

To check for presence of eyeball - check for eyelids

One eye or fused two eyes.

Often reflect basic defects in the anterior brain - secondary to notocord necrosis

A hole in one of the structures of the eye.

Can involve iris, retina, and/or sclera

Segmental anomaly affecting the surface ectoderm

(choristoma = well-differentiated tissue in the wrong place)

Part of the cornea follows a "skin" program of differentiation

Segmental anomaly of surface ectoderm

Inherited defects of lens or heat shock proteins

Focal/global injury to lens

Attachment of persistent vessels

However, some inherited cataracts develop later and thus are not congenital

Anomaly due to absence of vascular involution, anterior eye

Normal up to 6 months in dogs; Basenjis 6-8 months, but after that abnormal

Anomaly of the posterior vascular involution

Normal up to 3 wks in foals, 9 wks in puppies and kittens

Becomes Mittendorf's dot and Burgmeister's papilla

Incomplete formation of the trabecular meshwork --> aqueous humor not absorbed.

Manifestations occur later in life

Covered w/glaucoma

Anomaly in the neuroectoderm

Genetic causes: retinal folds or true dysplasia

Postinfectious: BVD, BT

Part of multiple anomalies:  Labradors and Samoyeds, with associated dwarfism

Relatively late failure of ganglion cells

Hypoplasia - failure of the ganglion cell axons to grow back towards the brain

FALSE!!

Great differences btwn affected littermates in regard to severity of phenotype

Also - any visible lesion is genetically significant, with potential transmission of a severe phenotype to next generation

Occurs in collies, shelties, Australian shepherds

A genetic test for CEA is available

1. Defect of choroidal maturation, w/posterior coloboma and choroidal hypoplasia, retinal detachment, hyphema

2. Tortuous retinal vessels

3. W/choroidal failure, there is an absence of scleral stimulation, which produces the colobomatous outpocket

Adenomas

Benign

1. Meibomian gland tumors

2. Adenomas

3. Papillomas

4. Melanocytomas

Inflammation of the conjunctiva

Probably the most common ocular condition seen by veterinarians

Common etiologies - Moraxella bovis, Mycoplasma, Chlamydophila

Allergic, including drugs put in the eye by vets

Gross reddening and exudates

1. Conjunctivitis - used in diagnosis, but is just one of many disease manifestation

2. Dacryoadenitis (tear gland inflammation) --> keratoconjunctivitis sicca

3. Retinitis

4. Optic neuritis

5. Keratitis (ferrets)

Hematocyst

Hemangioma

Hemangiosarcoma

Usually begin at limbus and spread over the cornea

Plaque --> papilloma --> carcinoma in situ --> carcinoma

Want to look at both eyes

1. Lamina fusca (varies in thickness; thin at limbus in horses)

2. Episclera

3. Lamina cribosa

1. Structural interruptions

2. Episcleritis (may be part of panophthalmitis; may be nodular)

3. Neoplasia:  melonoma (benign)

4. Melanosis

5. Hemorrhages

TRUE!

Scleral hemorrhages common

Associated lesions in other areas

Platelet consumption or coagulopathy

1. Lacrimal gland neoplasms

2. Lymphosarcoma

3. Extension of tumors from oral cavity, nasal cavity, salivary glands

4. Optic nerve meningioma may contain bone and cartilage in dogs; orbital myofibroblastic sarcomas in cats, which arise in the sclera

5. Osteosarcomas of the bony orbit

6. Non-neoplastic: mucocele or retrobulbar abscess

Keratinocytes:

Corneal epithelium

Epithelial basement membrane

Corneal stromal cells

Regular collagen spacing

Dehydrated stroma (5X)

Keeps corneal stroma dry from the inside:

1. Common in moribund neonates that don't blink or animals that can't close their eyes (exposure keratopathy/dessicatino keratitis)

2. Common w/keratoconjunctivitis sicca (reduced tear film)

Need to look for the cause of the problem!

A primary disorder of the tear film.

Can result from tear deficiency (dacryoadenitis coronavirus of rats; canine distemper in dogs), Meibomian/lacrimal gland diseae

Look at the lacrimal apparatus for pertinent pathology

Recurrent corneal erosions

Occur in middle aged dogs and horses

The cornea tries to regrow but can't stick as a result of abnormal stroma