Term
| What is the least discriminatory reflex for vision assessmet? |
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Definition
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Term
| Which of the vision assessments can test individual eyes? |
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Definition
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Term
| Describe the results of a vision assessment with a blind dog. |
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Definition
-negative menace reflex
-negative tracking
-obstacle course: bumps into things and just redirects, smells objects, responds to verbal stimuli |
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Term
| Describe a neurologic vision assessment's results. |
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Definition
-negative menace reflex
-negative tracking
-obstacle course: does not bump, may demontrate obsessive.compulsive pacing behavior with altered response to obstacles, may become stuck in a corner or between obstacles and make no attempt to redirect |
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Term
| What is the purpose of the palpebral reflex? |
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Definition
| -assess the ability of the eyelids to blink |
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Term
| What is the cranial nerve for the afferent and efferent arms of the menace relfex? |
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Definition
-afferent: CNII optic nerve
-efferent: CNVI facial nerve |
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Term
| What are the cranial nerves for the afferent and efferent arms of the palpebral reflex? |
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Definition
-afferent: CNV trigeminal nerve
-efferent: CNVII facial nerve |
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Term
| When can we get a false positive palpebral reflex? |
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Definition
| -when an animal cannot blink due to facial nerve paralysis, the abducent CN VI will retract the globe to compensate |
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Term
| How do we distinguish between a real and false positive palpebral reflex? |
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Definition
| -third eyelid will raise with a false positive ONLY |
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Term
| What is the afferent pathway of the pupillary light reflex? |
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Definition
| -retina => optic nerve => optic chiasm |
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Term
| What is the efferent pathway of the pupillary light reflex? |
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Definition
| -parasympathetic fibers running with CN III oculomotor => ciliary ganglion in orbit => iris |
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Term
| What are the common lesions of the retina that affect pupillary light reflex? |
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Definition
| -detachment and degeneration |
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Term
| What are the common pathologies of the optic nerve that affect the pupillary light reflex? |
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Definition
-inflammation
-neoplasia
-degeneration: post-proptosis, glaucoma
-compression: masticatory myositis |
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Term
| What pathology affects the otpic chiasm that will affect the pupillarylight relfex? |
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Definition
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Term
| Where are the common efferent PLR areas of pathology affecting the pupillary light reflex? |
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Definition
-parasympathetic fibers running with CN III oculomotor nerve
-ciliary ganglion in the orbit |
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Term
| What commonly affects the ciliary ganglion in the orbit of the eye affecting the pupillary light reflex? |
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Definition
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Term
| What pathologies affect the iris that can affect the pupillary light reflexes? |
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Definition
-atropine
-iris muscle atrophy
-adhesions of the iris to the lens from inflammation
-infiltrative disease of the ris
-glaucoma |
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Term
| What are the components of the visual pathway? |
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Definition
-Clear media: cornea, aqueous, lens, vitreous
-retina
-optic nerve
-chiasm
-optic triacts
-optic radiations
-visual cortex |
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Term
| What are the afferent components of the PLR pathway? Efferent components? |
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Definition
-Afferent: retina, optic nerve, chiasm
-Efferent: parasympathetic fibers of CN III, ciliary ganglion, iris constrictor muscle |
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Term
| True or FAlse: A cortically blind animal will not have a normal PLR. |
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Definition
| -FALSE, a cortically blind animal will have a normal PLR |
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Term
How will a lesion in the following locations affect the pupillary light reflexes?
a) retina
b) optic nerve(s)
c) chiasm
d) visual cortex of the brain |
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Definition
a) most commonly weak but can be variable
b) max dialated pupils with absent PLR
c) max dilated pupils with absent PLR
d) normal PLRs |
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Term
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Definition
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Term
| Describe the innervation of the dilator muscle as opposed to the constrictor muscle. |
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Definition
-DIlatory muscle: under sympathetic control
-Constrictor muscle: under parasympathetic control |
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Term
| What happens to the pupil if it looses sympathetic control? WHat about if it loses parasympathetic control? |
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Definition
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Term
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Definition
| -drooping of hte upper eyelid due to loss of sympahtetic innervation to Muller's smooth muscle in the superior eyelid |
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Term
| What are the clinical signs of Horner's syndrome? |
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Definition
-miosis
-prolapsed nictitants
-ptosis
-NO BLEPHAROSPASM |
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Term
| What are the clinical signs of HOrner's syndrome in horses? |
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Definition
-ptosis
-sweating on head and neck of affected side
-increased warmth of head and neck on affeced side
-only subtle miosis and nictitans prolapse |
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Term
| What are the etiologies of horner's syndrome in dogs and cats? |
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Definition
-idiopathic (70%): Goldens
-otitis media/ interna
-aggressive ear cleaning
-thoracic mass: mediastinal lymphoma in cats |
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Term
| What are the etiologies of horner's syndrome in horses? |
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Definition
-equine protozoal myeloencephalitis
-jugular venipuncture attempts or perivascular injection |
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Term
| What diagnostics do we perform for Horner's syndrome? |
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Definition
-otoscopic exam
-imaging of tympanic bulla
-thoracic rads |
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Term
| How do we treat horner's syndrome? |
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Definition
| -no treatment: non-painful, does not affect vision |
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Term
| What are the clinical signs of favial nerve paralysis? |
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Definition
-negative palpabral reflex with normal facial sensation
-tearing over flaccid lower eyelid
-ipsilateral ear and lip droop
-may see globe retraction and nictitans prolapse |
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Term
| What are the etiologies of facial nerve paralysis? |
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Definition
-otitis media/ interna
-folowing total ear canal ablation surgery
-idiopathic (Cockers)
-hypothyroud neuropathy
-trauma: especially in equine, FA, camelids
-neoplasia |
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Term
| How do we treat facial nerve paralysis? What about in the case of exposure keratopathy? |
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Definition
-treatment not usually required
-lubricants, temporary tarsorrhapthy especially in lLA, lateral peranent tarsorrhapthy |
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