Ophthalmic Exam Flashcards
(43 cards)
1
Q
What ophthalmic disease is associated with Merle coat color?
A
Merle ocular dysgenesis
2
Q
What history questions are important to ask during an ophthalmic exam?
A
- Duration of problem
- Unilateral vs bilateral
- Difficulty seeing
- day vs night vision
- Signs of pain
- squinting, rubbing at eye
- ocular discharge
- serous, mucoid, purulent
- Color change
- redness, cloudiness
- Medications
- duration, frequency, response
- General health concerns
- Other pets in the households
3
Q
What supplies are needed for an ophthalmic exam?
A
- Quiet dark room
- Magnification
- Optivisor, loupes, otoscope
- Finoff transilluminator
- Schirmer tear test strips
- Fluorescein dye/eyewash
- Direct ophthalmoscope
- Indirect lense
- 28, 20 diopter
- Proparacaine (anesthetic)
- Tropicamide (mydriatic)
4
Q
When should animals be sedated for ophthalmic exams
A
- Miosis/mydriasis (constricted/dilated pupil)
- Third eyelid protrusion/ventral globe rotation
- Decrease tear production and alter IOP
5
Q
What observations can be made about the animal without the use of ophthalmic instruments?
A
- visual vs. nonvisual behavior
- facial symmetry
- Size and Shape of the orbit/globe
- ocular discharge
- eyelid position
- Ocular opacities
- BCS
- Temperament
6
Q
What tests make up the Neuro-Ophthalmic Exam?
A
- Menace response
- Pupillary light reflex (PLR)
- Palpebral reflex
- Corneal reflex
- Dazzle reflex
7
Q
What is the Menace Response and what is it testing?
A
- Stimulus: motion of hand/fingers coming toward the eye
- Receptor: retina
- Afferent: Optic nerve (CNII)
- Efferent: Facial nerve (CNVII)
- Effector: Orbicularis oculi
- Response: Blink
8
Q
What are key points to remember about testing the Menace response?
A
- The opposite eye should be covered
- Don’t touch the facial hairs with testing hand
- Response is absent in puppies <4mo as it is a learned response
9
Q
What is the Pupillary Light Reflex (PLR) and what is it testing?
A
- Stimulus: light
- Receptor: Retina
- Afferent: optic nerve (CNII)
- Efferent: Oculomotor (CNIII)
- Effector: Iris sphincter muscle
- Response: Pupillary constriction
- Direct PLR
- Indirect/consensual PLR
10
Q
What is the PLR pathway?
A
- Optic nerve to Optic chiasm
- Optic tract
- ~20% of fibers to pretectal nuclei
- Decussation (majority of fibers)
- From Pretectal nuclei to Parasympathetic nuclei of the Oculomortor nerve (CNIII) (Edinger Westphal nuclei)
- Parasympathetic fibers of CN III synapse in ciliary ganglion
- short posterior ciliary nerves terminate in the iris sphincter
11
Q
What are some key points of the PLR pathway
A
- Direct PLR = constriction of the stimulated eye
- Indirect/Consensual PLR = Constriction in contralateral, unstimulated eye
- PLR response does not test vision
- Fibers for PLR branch off the optic tract before the Lateral geniculate nucleaus
- Animals blind from cortical disease can have normal PLRs
- Animals with negative PLRs can still be visual
- Fibers for PLR branch off the optic tract before the Lateral geniculate nucleaus
12
Q
What is the Palpebral/corneal Reflex and what is it testing?
A
- Stimulus: Touch
- Receptor: Skin/cornea
- Afferent: Trigeminal nerve (CNV)
- Efferent: Facial nerve (CNVII)
- Effector: Obicularis oculi
- Response: Blink
13
Q
What is the Dazzle Reflex and what is it testing?
A
- Stimulus: Bright light
- Receptor: Retina
- Afferent: Optic nerve (CNII)
- Interneuron: CNS/Subcortical
- Efferent: Facial nerve (CNVII)
- Effector: Obicularis oculi muscle
- Response:: Blink
14
Q
What are key points of the Dazzle Reflex?
A
- Especially useful when fundus can not be visualized
- hyphema (accumulated red blood cells (RBC) in the anterior chamber of the eye)
- Severe corneal disease
- Cataracts
- No need to test if Menace Response is positive
15
Q
How is the Orbit examined
A
- Assess orbital symmetry
- Palpation
- Globe and TEL position
- Retropulsion of globe
- Oral examination
- Pterygopalatine fossa caudal to last upper molar
- Orbital disease
- Pain on opening mouth
- Inability to open mouth
16
Q
What is the Adnexa and how is it examined?
A
- Adnexa:
- eyelids, conjunctiva, nasolacrimal system
- Variations of normal for species/breed
- Circumferential third eyelid (red arrow)
- Nonpigmented TE margin
- Haired lacrimal caruncle
- Examine Upper and lower eyelids
- General: palpebral fissure size, skin condition, discharge, blepharospasm
- Lid apposition and closure
- Incomplete = lagophthalmos
- Facial hairs contacting eye
- nasal fold, or medial canthal trichiasis
- Eylid masses
- Eyelid lacerations
- Eyelids rolling inwards (entropion)
- Eyelids rolling outward (ectropion)
- Lid Margins and underside of lids
- Distichia (eyelids arise from melbomian glands)
- ectopic cilia
- impacted melbomian glands
17
Q
What is this condition
A
- Macropalpebral fissure
- can be normal breed variation (shitzus, etc)
18
Q
How is the Nictitating membrane examined?
A
- Retropulse the globe
- examine for masses, scrolled cartilage, prolapsed glands
- Examine behind third eyelid for foreign bodies
- Topical anesthetic
- grasp w/forceps and evert or pull forward with a cotton tipped swap
19
Q
How should the Conjunctiva and sclera be examined?
A
- Conjunctiva:
- Evaluate bulbar and palpebral surfaces for injected vessels, bleeding, swelling, masses, foreign bodies, etc
- Sclera:
- evaluate for episcleral vessel congestion, masses, etc.
20
Q
A
Subconjunctival hemorrhage
21
Q
A
Nodular granulomatous episcleritis
22
Q
What should the Anterior Chamber be examined for?
A
- should be clear
- Anterior Chamber depth
- Aqueous flare
- protein in aqueous humor
- Use a focal light source
- Hyphema
- blood in anterior chamber
- Hypopyon
- WBC in anterior chamber
- Masses
- cysts, tumors
- Anterior lens luxation
23
Q
What should the Cornea be examined for?
A
- Should be clear
- Red: vessels
- Blue: edema
- White: Scar, lipid, WBC, calcium
- Brown: pigment, foreign bodies
24
Q
What should the Iris/pupil be examined for?
A
- Iris:
- color change
- Masses
- Hemorrhage
- Pupil:
- Dilated / Constricted
- Different sizes (anisocoria)
- Abnormal shape (dyscoria)
25
What should the lens be examined for?
* Position of lens
* Should be Clear
* Cloudiness from the lens hardening- Nuclear sclerosis
* can still see through!
* Opacity in the lens - cataract
* diminishes vision
26
How is the posterior of the eye examined?
* Includes: Vitreous, retina, optic nerve head
* Evaluate:
* ONH size, shape, and myelination
* Retinal vasculature
* Tapetal reflectivity
* Dilation of pupil
* 1% Tropicamide
* Cholinergic antagonist
27
What are the options for Ophthalmoscopy?
* Direct Opthlamoscopy
* Indirect Opthalmoscopy
28
What is Direct Ophthalmoscopy
* Give Real, upright image
* Higher magnification
* Monocular view
* Small field of view
* Useful for close examination of optic nerve/retinal lesions
* Dangerous w/ some patients
29
What is Indirect ophthalmoscopy
* Image is upside down and backwards
* Lower magnification
* Binocular or monocular view
* Larger field of view
* Higher diopter = lower magnification
* lower diopter = higher magnification
30
What diagnostic tests can be done on the eye?
* Culture and sensitivity
* Cytology
* Schirmer Tear Test (STT)
* Fluorescein dye
* Tonometry
* Nasolacrimal Flush
31
When/How is culture and sensitivity performed on the eye?
* Suspected infection
* \*Bacteria can frequently be cultured at low numbers form normal conjunctiva!
* *Staphylococcus spp, streptococcus spp, Cornybacterium,* and *Bacillus spp*
* Use Moistened mini-tip swabs
* Provide Topical anesthesia
* Avoid contamination of sample, and of eye
* For ulcers - culture from the periphery
* Run aerobic bacterial +/- fungal culture
32
Why is atropine not used to dilate eyes in animals?
effects are long lasting (2 weeks!)
33
How should a cytology sample be taken from the eye?
* Provide topical anesthetic
* Use: Kimura platinum spatula, blunt end of a surgical blade, or a cytobrush
* Do NOT use a cotton swab - does not transfer cells to the slide well
34
What is the Schirmer Tear Test (STT)?
* Measures aqueous component
* Basal tears
* Reflex tears
* Prior to topical anesthesia (decreases tear production)
* Remove strip after 60 sec
* Normal \> 15mm/min dog
* Do not routinely perform in Horses or cats
35
When is Fluorescein Stain?
* Corneal ulcer
* Jones test
* Tear film break up time
* Seidel test
36
How are corneal ulcers tested for?
* Water soluble dye
* Intact corneal epithelium is hydrophobic (lipophilic) and does not retain fluorescein
* hydrophilic stroma retains fluorescein
* Descemet's membrane is hydrophobic and retain fluorescein dye
* Application:
* Moisten strip with saline
* Apply to ocular surface
* Rinse
* Assess for dye retention - Cobalt blue light
37
What is the Jones test
* Evaluates patency of nasolacrimal system
* Apply fluorescein stain to ocular surface rinse
* Hold nose down and examine nostrils
* Examine oral cavity
* Normal passage \< 5 min
38
What is Tear Film Break-up Time?
* Tear quality assessment
* Moisten strip with saline and apply to cornea
* Do NOT rinse
* Blink eyelid
* Hold lids open and monitor for “dry spots”
* Normal tear break-up time \>20 seconds
39
What is the Seidel Test?
* Aqueous humor leakage
* Corneal lacerations
* Rupture ulcers
* Surgical incision
* Apply Fluorescein
* Do NOT rinse
* If leaking will create a river
40
What is Tonometry?
* Measures intraocular pressure
* Normal 15-25 mmHg
* Applanation - Tono-Pen®
* Induction-impact - Tonovet®
41
What is applanation?
* Measures force required to flatten corneal surface
* Fast and easy
* Technique - easy to falsely elevate
* topical anesthetic (proparacaine)
* Restraint
* Eyelid retraction
* Measurement:
* 5% 10% 20% or \>20% variance
* lowest reading (5% or less)
42
What is Induction-impaction tonometery
* Measures rebound action of magnetic probe as it contacts the cornea and bounces back
* Does not require topical anesthetic
43
How is a nasolacrimal flush done?
* Topical anesthetic
* cannulate superior puncta w/ flexible catheter or canula attached to a syringe
* Flush saline form superior to inferior puncta, then occlude inferior puncta w/ digital pressure and flush into the nasal cavity
