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Medicine I > Ophthalmic Exam > Flashcards

Ophthalmic Exam Flashcards

1
Q

What ophthalmic disease is associated with Merle coat color?

A

Merle ocular dysgenesis

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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
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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)
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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
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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
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6
Q

What tests make up the Neuro-Ophthalmic Exam?

A
  • Menace response
  • Pupillary light reflex (PLR)
  • Palpebral reflex
  • Corneal reflex
  • Dazzle reflex
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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
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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
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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
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10
Q

What is the PLR pathway?

A
  1. Optic nerve to Optic chiasm
  2. Optic tract
    1. ~20% of fibers to pretectal nuclei
    2. Decussation (majority of fibers)
  3. From Pretectal nuclei to Parasympathetic nuclei of the Oculomortor nerve (CNIII) (Edinger Westphal nuclei)
  4. Parasympathetic fibers of CN III synapse in ciliary ganglion
  5. short posterior ciliary nerves terminate in the iris sphincter
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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
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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
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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
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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
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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
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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
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17
Q

What is this condition

A
  • Macropalpebral fissure
    • can be normal breed variation (shitzus, etc)
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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
Q

What should the lens be examined for?

A
  • 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
Q

How is the posterior of the eye examined?

A
  • Includes: Vitreous, retina, optic nerve head
  • Evaluate:
    • ONH size, shape, and myelination
    • Retinal vasculature
    • Tapetal reflectivity
  • Dilation of pupil
    • 1% Tropicamide
      • Cholinergic antagonist
27
Q

What are the options for Ophthalmoscopy?

A
  • Direct Opthlamoscopy
  • Indirect Opthalmoscopy
28
Q

What is Direct Ophthalmoscopy

A
  • 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
Q

What is Indirect ophthalmoscopy

A
  • 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
Q

What diagnostic tests can be done on the eye?

A
  • Culture and sensitivity
  • Cytology
  • Schirmer Tear Test (STT)
  • Fluorescein dye
  • Tonometry
  • Nasolacrimal Flush
31
Q

When/How is culture and sensitivity performed on the eye?

A
  • 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
Q

Why is atropine not used to dilate eyes in animals?

A

effects are long lasting (2 weeks!)

33
Q

How should a cytology sample be taken from the eye?

A
  • 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
Q

What is the Schirmer Tear Test (STT)?

A
  • 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
Q

When is Fluorescein Stain?

A
  • Corneal ulcer
  • Jones test
  • Tear film break up time
  • Seidel test
36
Q

How are corneal ulcers tested for?

A
  • 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
Q

What is the Jones test

A
  • 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
Q

What is Tear Film Break-up Time?

A
  • 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
Q

What is the Seidel Test?

A
  • Aqueous humor leakage
    • Corneal lacerations
    • Rupture ulcers
    • Surgical incision
  • Apply Fluorescein
  • Do NOT rinse
  • If leaking will create a river
40
Q

What is Tonometry?

A
  • Measures intraocular pressure
    • Normal 15-25 mmHg
  • Applanation - Tono-Pen®
  • Induction-impact - Tonovet®
41
Q

What is applanation?

A
  • 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
Q

What is Induction-impaction tonometery

A
  • Measures rebound action of magnetic probe as it contacts the cornea and bounces back
  • Does not require topical anesthetic
43
Q

How is a nasolacrimal flush done?

A
  • 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

Medicine I (43 decks)

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