Ophthalmology (Impt. parts)

Question 1

Initial eye exam

Answer 1

Occur prior to sedation in well lit area
Menace response, maze testing and evaluation of pupillary light reflex before sedation

Question 2

Downward direction of eyelashes

Answer 2

Blepharospasm
Enophthalmos
Ptosis

Question 3

Upward deviation of lashes

Answer 3

Exophthalmos or enlarged eye

Question 4

Cranial nerve evaluation

Answer 4

2-7
Assessed via menace response, pupillary light/ dazzle reflexes, globe and eyelid position sensation of ocular and adnexal structures

Question 5

Sympathetic nerve system

Answer 5

Controls dilation of pupils and other motor function of the eyes and face
Damage → Horner’s syndrome (miosis, ptosis)

Question 6

Parasympathetic nervous system

Answer 6

Edinger-Westphal nucleus (oculomotor- CN8)
Constrictor muscle of the iris
CN7- facial → lacrimation when stimulated

Question 7

Restraint

Answer 7

Detomidine HCl + lip and neck twitch if needed

Question 8

Regional nerve blocks

Answer 8

Auriculopalpebral (palpebral branch of the facial nerve)
Frontal (supraorbital) branch of trigeminal (CN5)
Akinesia and anesthesia of upper eyelid occurs

Question 9

What is the most common nerve block (motor)?

Answer 9

Palpebral branch of the auriculopalpebral nerve that innervates the orbicularis oculi muscle (strong m)

Question 10

What provides sensation to the eyelids?

Answer 10

Ophthalmic and maxillary divisions of the trigeminal nerve (CNV)

Question 11

What block is required for exam (sensory)?

Answer 11

Frontal (supraorbital) that innervates most of the central upper eyelid

Question 12

What’s used for cornea and sclera examination?

Answer 12

Diffuse and focal direct illumination with magnification then biomicroscopy (cornea) using a slit lamp

Question 13

What should be done b4 placing meds in the eye?

Answer 13

Cx (sterile dacron-tipped swabs) and Schirmer tear values

Question 14

What does cx and sensitivity aid in?

Answer 14

Dx of infectious keratitis and help determine antibmicrobial therapy
Use blunt end of sx blade

Question 15

Cytology

Answer 15

Collected after testing the corneal reflex if needed
Apply 0.5% proparacaine hydrochloride (HCl) topical anesthetic
Tools: Dacron tipped swabs, blunt end of sterile scalpel and cytobrushes and spatulas

Question 16

Seidel test

Answer 16

Used to assess the presence of anterior chamber leakage in the cornea
Screening test for corneal trauma, perforation and degernation

Question 17

Rose Bengal staining

Answer 17

For deficiency of preocular tear film
Fluorescein stain first then Rose second

Question 18

Tonometry

Answer 18

Horses with focal or diffuse corneal edema, red or painful eye, orbital trauma, hx f glaucoma, lens luxation

Question 19

Examining the lens and posterior segment

Answer 19

Mydriasis required (tropicamide)- blocks responses of iris sphincter muscle to the iris and ciliary muscles to cholingeric stimulation → dilation and pupil and paralysis of ciliary muscle

Question 20

How to test the nasolacrimal duct

Answer 20

Jones test

Question 21

Indications for a U/S

Answer 21

When view to glob obscured: cornea edema, intra-ocular hemorrhage/ pus, cataracts, chemosis, trauma

Question 22

Prep for an U/S

Answer 22

Sedation, auriculopalpebral block, topical local anesthetic agent to surface of the cornea