Ophthalmology Flashcards
What does the menace response test
Retina Optic nerve (afferent) Optique radiation Visual cortex Cerebrocortical connections Facial nerve (efferent- orbicularis oculi)
Oculopalpebral reflex
What nerves does it test
Trigeminal (afferent)
Facial (efferent)
Oculopalpebral reflex: reduction or prevention of lid closure is caused by
Facial paralysis
Oculomotor neuropathy
Physical abnormalities (lagophthalmos, exophthalmos)
Dazzle reflex
Afferent: retina and CN II OPTIC
Supraoptic nuclei if hypothalamus and rostral canniculus
Efferent: CN VII (facial) (orbicularis oculi)
Abnormal: stress, non cortical blindness, pathology in mesencephalon, Facial n
Normal with cortical blindness
Pupillary light reflexes
Afferent: retina and optic n, optic chiasm, optic tract to EE oculomotor nucleus, pretectal zone in midbrain
Efferent: parasympathetic fibres of the oculomotor nerve and short ciliary nerves to iris constrictor
Decussation at optic chiasm
Dog - 75%
Cat - 65% (then cross back between pretectal nucleus and oculomotor nucleus) in midbrain
Corneal reflex afferent and efferent
Afferent : ophthalmic branch do trigeminal n
Efferent: facial (orbicularis oculi) and abducens (retractor bulbi)
Vestibule-ocular reflex (physiological nystagmus)
Afferent: vestibulocochlear n
Efferent: oculomotor, trochlear and abducens
Causes of horners syndrome
Cervical spinal cord
Thoracic t1-t3 spinal cord
Brachial plexus
Midbrain, middle ear, eye
Infectious causes of chorioretinitis
CDV
Canine herpes virus
FIP
FIV
Ehrlichiosis
Rocky Mountain spotted fever
Bartonella
Leptospirosis
Brucellosis (lymes)
Mycobacterium
Fungal
Protozoal - toxoplasmosis
Neosporosis
Leishmaniasis
Toxocara
Angiostrongylus
Non-infectious causes of chhorioretinitis
Neoplasia - mestastatic lymphoma or primary
Uveodermatological syndrome (akitas)
Traumatic
Immune-mediated
Idiopathic -Granulomatous meningoencephalitis
causes of optic neuritis
Neoplasia
Immune mediated
Infectious
Distemper Toxoplasmosis Ehrlichiosis Tick borne encephalitis Blastomycosis Cryptococcosis Histoplasmosis
Causes of retinal detachment
Hypertension Hyperviscosity (myeloma, lymphoma, ehrlichia) Trauma Glaucoma Lens surgery Steroid responsive Chorioretinitis (FIP, toxoplasmosis) Neoplasia
Prognosis of FeLV positive cats with ocular lymphosarcoma
Poor
Treatment of FeLV related ocular lymphoma
Chemotherapy
Radiotherapy
Topical steroids
Causes of uveitis in cats
Trauma Lens luxation Ulcerative keratitis FIP Lymphoma Toxoplasmosis Leishmania Systemic mycosis (cryptococcus, blastomycosis, coccidiomycoses, candidiasis) Idiopathic Primary uveal neoplasia FIV Larval migrants, curterebra (FeLV) Bartonella, mycobacterium, Ehrlichia, borrelia
Causes of uveitis in dogs
Trauma Lens luxation Distemper, infectious canine hepatitis Mycotic disease Ehrlichiosis and anaplasma platys Lyme borreliosis Toxoplasma, leishmania, neosporosis Parasites: dirofilaria, angiostrongylus Lymphoma,systemic histiocytosis Systemic hypertension Hyperlipidaemia Hyperviscosity syndrome Uveodermatological syndrome Hypothyroidism
Prognostic factors in cats with lymphoma
Anatomic locations -nasal and mediastinal (Siamese) better prognosis Clinical stage - unclear prognostic significance Small cell better than large cell Immunophenotype not prognostic BCS < 5/9 negative FeLV positive - negative Weight loss - negative Substage b - negative Low grade better than high grade
Poor prognostic indicators of lymphoma in the dog
Substage
Immunophenotype (B cell better than T cell)
Steroid pre-treatment
Cranial mediastinal lymphadenopathy
Location - hepatic poor prognosis, alimentary poor prognosis, rectal good, multicentric better than GI
Target lesions in liver characteristic of what?
Lymphoma and malignant histiocytosis
Why do we need biopsies for lymphoma and not just cytology
To determine grade - can’t be done on cytology
Need this for prognosis and treatment options
