Internal Ocular Pathology Flashcards
Hypopyon
Purulent inflammation in anterior chamber
Intra ocular inflammation
Anterior uveitis - inflammation of iris and ciliary body
Posterior uveitis - inflammation of choroid
- if retina involved too = chorioretinitis
Panuveitis - inflammation of all 3 components of uvea
Endophthalmitis - inflammation of uvea, retina, ocular cavities
Panophthalmitis - inflammation of entire globe including cornea and sclera
Anterior uveitis
- inflammation of iris and ciliary body
Posterior uveitis -
inflammation of choroid
- if retina involved too = chorioretinitis
Panuveitis -
inflammation of all 3 components of uvea
Endophthalmitis -
inflammation of uvea, retina, ocular cavities
(Anterior /posterior chamber, vitreous chamber)
Panophthalmitis -
inflammation of entire globe including cornea and sclera
Uveitis
Most cases reflect uveal involvement of systemic disease
- hematogenous bacterial infection
- immune mediated uveal inflammation
Indications for Canine uveitis
Idiopathic
Phacolytic uveitis
Trauma
Foreign body
Blastomycosis
Phacoclastic uveitis
Diseases of uvea
Lens induced uveitis
Systemic mycoses
Uveodermatologic syndrome
Feline uveitis
Equine uveitis
Phacolytic uveitis
Leakage of lens protein through the lens capsule - highly anti genetic
Occurs secondary to cataracts*
Phacoclastic uveitis
Release of lens protein through ruptured lens capsule
- traumatic rupture of lens capsule
- rapidly progressing diabetic cataracts*
Systemic mycoses
Blastomyces - common in dogs
Cryptococcosis - common in cats
Lesion: Pyogranulomatous endophthalmitis
Exudate accumulates in choroid and sub retinal space
Uveodermatologic syndrome aka VKH
“Vogt-koyanagi-harada syndrome”
Common in akitas, Siberian huskies, samoyeds
Immune mediated disease targeting melanin
- bilateral granulomatous uveitis (1st lesion)
-depigmentation of facial skin (2nd lesion)
Indications for Feline uveitis
Idiopathic
Cryptococcosis
Feline infectious peritonitis
FIP
Mutated enteric coronavirus
Pyogranulomatous inflammation in multiple organs
Causes immune mediated uveitis in eye
Equine uveitis
Equine recurrent uveitis (moon blindness)
Equine recurrent uveitis (moon blindness)
Repeated bouts of anterior uveitis occurring at unpredictable intervals; increases in severity over time
One of the most common causes of blindness in EQ
Proposed path of moon blindness
Hypersensitivity reaction to
- leptospira antigen
- onchoncerca cervicalis microfilaria
Genetic susceptibility
- Appaloosa, German warm blood
Diseases of lens
Lens luxation
Cataract
- diabetic cataract
-secondary cataract
-age related cataract
Glaucoma - primary/secondary
lens luxation
Complete dislocation of lens
Can fall into anterior chamber or remain in posterior
Anterior luxation predisposed to glaucoma - mechanical obstruction of aqueous fluid (pupillary blockage)
causes of lens luxation
Primary - no known trauma or other ocular disease
Could be congenital or aquired (spontaneous)
Secondary - blunt trauma, glaucoma
Cataract
Lenticular opacity
Diabetic
Secondary - uveitis, glaucoma, neoplasia, advanced retinal degeneration
Age related
Diabetic cataract
Bilateral cataracts are common (70%) in diabetic dogs
^ glucose in aqueous -> shunts to sorbitol synthesis -> excess sorbitol osmotically attracts water -> swelling & degeneration of lens fibers -> cataracts
Glaucoma
Sustained increase intraocular fluid pressure
-damages retina and optic nerve
- leads to vision loss
- results in impaired outflow of aqueous* (uveitis, inflammatory blocks outflow)
Common development of glaucoma
Dogs > cats > horses
Most common reason for enucleation in dogs & cats
primary glaucoma
Goniodysgenesis
Incomplete atrophy of ciliary cleft mesenchyme
Abnormality of development
Delayed onset of clinical glaucoma (5+ yr)
Open angle glaucoma
No primary histo logic lesion
Secondary glaucoma
Any primary lesion that obstructs aqueous flow through the pupil or trabecular mesh work (ciliary cleft)
Pupillary block in secondary glaucoma
Obstruction of aqueous through pupil
Anterior lens luxation
Lens capsule rupture
Trabecular occlusion in secondary glaucoma
Neoplasia
Preiridial fibrovascular membrane
Mechanical compression
- cataracts, posterior chamber neoplasms
Lesions of glaucoma
Result from increased intraocular pressure regardless of cause
Depend on degree of pressure elevation, duration & quickness of onset
Gross lesions of glaucoma
Buphthalmos
Buphthalmos - stretching of globe secondary to increased intraocular pressure - can prevent eyelids from closing = corneal Dessication
Gross lesions of glaucoma
Corneal edema
Pressure induced injury to corneal endothelium
Gross lesion of glaucoma
Atrophy
Atrophy of iris and ciliary body
Chronic pressure induced ischemia
Late in course of disease
Microscopic lesions of glaucoma
Atrophy of nerve fiber layer & ganglion cell layer
Loss of neurons from inner nuclear layer
Collapse of trabecular mesh work
Optic nerve atrophy
Optic disc cupping
Corneal edema
Cararacts
Ocular neoplasia
Uveal neoplasms - dogs, cats, horses
Uveal melanocytoma - dog
Most common primary intraocular tumor in dogs
Almost always benign
Can cause secondary glaucoma
iridociliary adenoma - dogs
Almost always benign
Uveal neoplasms - cat
Diffuse iris melanoma
Iridociliary adenoma
Primary ocular sarcoma
Ocular neoplasms - horses
Uveal melanocytoma
Topic nerve tumors
Neoplasms metastatic to globe
Diffuse Iris melanoma
Cat
Starts as unilateral hyperpigmentation - progresses to diffuse Iris involvement
Iridociliary adenoma
Primary ocular sarcoma
Cat
Post traumatic sarcoma
Spindle cell sarcoma that develops secondary to lens rupture
Uveal melanocytoma- horse
Common in gray horses
Similarly to uveal melanocytoma in dogs
optic nerve tumors
Meningiomas
Most common in dogs
Metastasis is uncommon
Neoplasms metastatic to globe
Lymphoma
Carcinomas
