Ocular Flashcards
What are possible causes of corneal edema?
- injury to epithelium (ulceration)
- injury to endothelium (dystrophy, increased IOP, immune-mediated)
- keratitis: leaky neovascularization
What is Blue Eye?
corneal edema resulting from survival of infectious canine hepatitis infection
- immune complex deposition in corneal epithelium
What is Hyphema?
blood in the anterior chamber
What is buphthalmos?
enlarged eye due to accumulation of fluid
What is the cause of primary glaucoma?
goniodysgenesis: a detectable malformation of the trabcular meshwork
What are causes of secondary glaucoma?
anything that obstructs the pupil or trabecular meshwork
- exudate
- lens luxation
- posterior or anterior synechia
- compression of filtration angle
What is cataract?
- most common disease of the lens
- swelling/degeneration of lenticular fibers leading to opacity
What is lenticular sclerosis?
- a senile change, not a cataract
- light can still come through
- lens fibers continue to differentiate throughout life
What are the indications of retinal degeneration and atrophy?
- decreased vascularity
- optic disc atrophy
- changes in tapetal reflection
What are the causes of retinal degeneration and atrophy?
- senile change
- inherited metabolic defect of photoreceptor cells
- toxicity
- metabolic deficiencies (taurine, vit A)
- increased IOP
- retinal detachment
What are the causes of retinal detachment?
- choroiditis, retinitis
- hemorrhage
- neoplasm
- trauma
What are the gross features of conjunctivitis?
- hyperemia
- swelling/edema
- discharge
- chemosis
- pigmentation
What are primary pathogen causes of conjunctivitis in cats?
- Herpesvirus
- Chlamydophilia
- Mycoplasma felis
What are the corneal responses to injury?
- edema
- epithelial regeneration
- neutrophil mediated stromal lysis
- nevascularization
- stromal fibrosis
Describe healing if the eye is only eroded
epithelial regeneration is very rapid
Describe healing if the eye is ulcerated
stromal repair must proceed epithelial regeneration
Describe healing if the eye has a chronic/persistent injury
- cutaneous metaplasia may occur
- cannot see out of the eye
What are possible etiologies of keratitis?
- trauma
- bacterial (Pseudomonas aeruginosa, Moraxella bovis)
- Chlamydia/Mycoplasma
- viruses: IBR, MCF, EHV-1
- fungi: aspergillosis, mucormycosis
- drying and desiccation: keratoconjunctivitis sicca
- idiopathic
What is keratomalacia?
- melting ulcers
- necrosis of corneal epithelium and stroma usually from leukocytes
What is corneal sequestration?
- localized necrosis of the epithelium and anterior stroma from severe corneal injury
- affected area gets infiltrated with dark pigment present in tear film
What is keratoconjunctivitis sicca?
Describe the pathogenesis
- dry eye
- immune-mediated injury to lacrimal glands > decreased tears and/or change in composition of tears > drying out of conjunctiva/cornea > chronic irritation
What is affected in anterior uveitis?
iris and ciliary body
What is affected in posterior uveitis?
choroid
What is affected in endophthalmitis?
uvea, retina, and vitreous
What is affected in panophthalmitis?
cornea and sclera
What are some causes of uveitis?
- hypersensitivity: feline idiopathic lymphoplasmacytic uveitis, equine recurrent uveitis
- infectious
- lens-induced
What are some consequences of uveitis?
- synechia
- preiridal fibrovascular membrane
- iris bombe
- cataracts
- lens luxation
- glaucoma
- retinal detachment
- phthisis bulbi
Define dyscoria
abnormal shape of pupil
What is the most common cause of blindness in equines?
equine recurrent uveitis
What is lens-induced uveitis?
What are the two types?
inflammatory response to lens proteins
- phacolytic: leakage of lens proteins from hypermature cataract
- phacoclastic: rupture of the lens
What are some causes of retinitis?
- extension of choroiditis or encephalitis
- neurotropic viral infections
- visceral larval migrans
What is collie eye anomaly?
What are the ophthalmoscopic findings?
- scleral ectasia
- retinal vessel tortuosity
- choroidal and tapetal hypoplasia
- optic nerve coloboma
- retinal separation with intraocular hemorrhage
What is a cause of cyclopia/synopthalmos?
ingestion of veratrum californicum on day 14 of gestation
What is microphthalmia?
when the globe is too small so the eyes do not open completely
What is corneal dermoid?
haired skin develops on the conjunctiva or cornea
What is a coloboma?
notch-like defects of optic disc, retina, and/or uvea as a result of defective closure of the embryonic fissure of the eye
Features of Feline diffuse Iris Melanoma
- most common intraocular neoplasm
- most are malignant: raised lesions, velvet surface, distortion of pupils/iris
- rate of glaucoma high
- rate of metastasis low
Features of Ciliary Adenoma/Carcinoma
- more often in dogs than cats
- most are benign
- discrete nodules in posterior segment
Features of intraocular sarcoma
- unique to cats
- arises following ocular trauma
- malignant
Features of uveal lymphoma
- most common metastasis involving the eye
- thickening/pallor of the uvea
- exudate in anterior chamber
