Ophthalmic Examination

Question 1

Examination Setting

Answer 1

• Quiet dark room
• Magnification
  
  • Optivisor , loupes, otoscope
• Finoff transilluminator
• Schirmer tear test strips
• Fluorescein dye/eyewash
• Direct ophthalmoscope
• Indirect lens
  
  • 28, 20 Diopter
• Proparacaine (anesthetic)
• Tropicamide (mydriatic)

Question 2

Restraint

Answer 2

• Examination table
• Important to steady the head
• Less is often more!!! (especially in cats)
• To sedate or not to sedate?
  
  • Miosis/mydriasis
  • Third eyelid protrusion/ventral globe rotation
  • Decrease tear production and alter IOP

Question 3

how far should light be

Answer 3

Bright focal light held an arm’s length distance

Question 4

Menace Response

Answer 4

• Stimulus: Motion
• Receptor: Retina
• Afferent: Optic nerve (II)
• Efferent: Facial nerve (VII)
• Effector: Orbicularis oculi
• Response: Blink
• Keys to remember
  
  • Cover opposite eye
  • Don’t touch facial hairs
  • Learned response (~4 months+)

Question 5

optic pathway

Answer 5

Question 6

Pupillary Light Reflex (PLR)

Answer 6

• Stimulus: Light
• Receptor: Retina
• Afferent: Optic nerve (II)
• Efferent: Oculomotor (III)
• Effector: Iris sphincter muscle
• Response: Pupillary constriction
  
  • Direct PLR
  • Indirect or consensual PLR

“indirect left to right” = light shining in left eye

Question 7

PLR Pathway

Answer 7

• Optic nerve to chiasm
• Optic tract
• ~20% of fibers to pretectal nuclei
• Decussation (majority of fibers)
• Parasympathetic nuclei of the oculormotor nerve (CN III)
• Parasympathetic fibers of CN III synapse in ciliary ganglion
• Short posterior ciliary nerves terminate in the iris sphincter
• Constriction of stimulated eye= direct PLR
• Constriction in contralateral, unstimulated eye=indirect or consensual PLR
• PLR ≠ Vision
• Fibers for PLR branch off optic tract before LGN
  
  • Animals blind from cortical disease can have normal PLRs
  • Eyes with negative PLRs can be visual

3 synapses: 1) pretectal nucleus, 2) edinger westphal nucleus, 3) ciliary ganglion

Question 8

Palpebral/corneal Reflexes

Answer 8

• Stimulus: Touch
• Receptor: Skin/cornea
• Afferent: Trigeminal nerve (V)
• Efferent: Facial nerve (VII)
• Effector: Orbicularis oculi
• Response: Blink

Question 9

Dazzle Reflex

Answer 9

• Stimulus: Bright light
• Receptor: Retina
• Afferent: Optic nerve (II)
• Interneuron: CNS/subcortical
• Efferent: Facial nerve (VII)
• Effector: Orbicularis oculi muscle
• Response: Blink
• Especially useful when fundus can not be visualized
  
  • Hyphema , severe corneal disease, cataracts
• No need to test if menace response is positive!!!!

only use if think they are blind!

does not involve visual cortex

Question 10

Examination of Orbit

Answer 10

• Assess orbital symmetry
  
  • Palpation
  • Globe and TEL position
  • Retropulsion of globe
• Oral examination
  
  • Pytergopalatine fossa caudal to last upper molar
  • Orbital disease
    
    • Pain on opening mouth
    • Inability to open mouth

only if think there is orbital disease

Question 11

Adnexal Examination

Answer 11

Question 12

Examine upper and lower eyelids

Answer 12

• General: palpebral fissure size, skin condition, discharge, blepharospasm
• Lid apposition and closure
  
  • Incomplete = lagophthalmos
• Facial hairs contacting eye?
  
  • Nasal fold or medial canthal trichiasis
• Eyelid masses
• Eyelid lacerations
• Eyelids rolling in (entropion)
• Eyelids rolling out (ectropion)
• Examine lid margins and underside of lids
  
  • Distichia , ectopic cilia, impacted meibomian glands

Question 13

Nictitans Examination

Answer 13

• Retropulse globe
  
  • Examine for mass, scrolled cartilage, prolapsed gland
• Examine behind third eyelid for foreign bodies
  
  • Apply topical anesthetic, grasp with a forceps and evert or pull forward with cotton tipped swab

Question 14

Conjunctiva and Sclera Exam

Answer 14

Question 15

color of cornea → why

Answer 15

Question 16

Examination of Anterior Chamber

Answer 16

should be completely black (shouldn’t notice it)

Question 17

Examination of Iris/Pupil

Answer 17

Question 18

Examination of the Lens

Answer 18

Question 19

Posterior Segment Exam

Answer 19

Question 20

Ophthalmoscopy

Answer 20

Question 21

Answer 21

Question 22

Culture and Sensitivity

Answer 22

Question 23

Cytology

Answer 23

Question 24

Schirmer Tear Test (STT)

Answer 24

Question 25

Fluorescein Stain

Answer 25

* Corneal ulcer * Jones test * Tear film break up time * Seidel test

Question 26

Corneal Ulcer

Answer 26

Question 27

Jones Test

Answer 27

* 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

Question 28

Tear Film Break-Up Time

Answer 28

* Tear quality assessment * Moisten strip with saline and apply to cornea * Do NOT rinse * Blink eyelids * Hold lids open and monitor for “dry spots” * Normal tear break up time \>20 seconds

Question 29

Seidel Test

Answer 29

* Aqueous humor leakage * Corneal lacerations * Ruptured ulcers * Surgical incisions * Apply fluorescein * Do NOT rinse * If leaking aqueous humor will create a “river”

Question 30

Tonometry

Answer 30

* Measures intraocular pressure * Normal 15-25 mmHg * Applanation * Tono-Pen® * Induction impact * Tonovet ®

Question 31

Tonopen®-applanation

Answer 31

* Measures force required to flatten corneal surface * Fast and easy to use

Question 32

Tono-pen®

Answer 32

Question 33

TonoVet®-induction-impaction

Answer 33

Question 34

Nasolacrimal Flush

Answer 34

* Topical anesthetic * Cannulate superior puncta with flexible catheter or canula attached to syringe * Flush saline from superior to inferior puncta, then occlude inferior puncta with digital pressure and flush into the nasal cavity