Ophthalmology (Impt. parts) Flashcards
Initial eye exam
Occur prior to sedation in well lit area
Menace response, maze testing and evaluation of pupillary light reflex before sedation
Downward direction of eyelashes
Blepharospasm
Enophthalmos
Ptosis
Upward deviation of lashes
Exophthalmos or enlarged eye
Cranial nerve evaluation
2-7
Assessed via menace response, pupillary light/ dazzle reflexes, globe and eyelid position sensation of ocular and adnexal structures
Sympathetic nerve system
Controls dilation of pupils and other motor function of the eyes and face
Damage → Horner’s syndrome (miosis, ptosis)
Parasympathetic nervous system
Edinger-Westphal nucleus (oculomotor- CN8)
Constrictor muscle of the iris
CN7- facial → lacrimation when stimulated
Restraint
Detomidine HCl + lip and neck twitch if needed
Regional nerve blocks
Auriculopalpebral (palpebral branch of the facial nerve)
Frontal (supraorbital) branch of trigeminal (CN5)
Akinesia and anesthesia of upper eyelid occurs
What is the most common nerve block (motor)?
Palpebral branch of the auriculopalpebral nerve that innervates the orbicularis oculi muscle (strong m)
What provides sensation to the eyelids?
Ophthalmic and maxillary divisions of the trigeminal nerve (CNV)
What block is required for exam (sensory)?
Frontal (supraorbital) that innervates most of the central upper eyelid
What’s used for cornea and sclera examination?
Diffuse and focal direct illumination with magnification then biomicroscopy (cornea) using a slit lamp
What should be done b4 placing meds in the eye?
Cx (sterile dacron-tipped swabs) and Schirmer tear values
What does cx and sensitivity aid in?
Dx of infectious keratitis and help determine antibmicrobial therapy
Use blunt end of sx blade
Cytology
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
Seidel test
Used to assess the presence of anterior chamber leakage in the cornea
Screening test for corneal trauma, perforation and degernation
Rose Bengal staining
For deficiency of preocular tear film
Fluorescein stain first then Rose second
Tonometry
Horses with focal or diffuse corneal edema, red or painful eye, orbital trauma, hx f glaucoma, lens luxation
Examining the lens and posterior segment
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
How to test the nasolacrimal duct
Jones test
Indications for a U/S
When view to glob obscured: cornea edema, intra-ocular hemorrhage/ pus, cataracts, chemosis, trauma
Prep for an U/S
Sedation, auriculopalpebral block, topical local anesthetic agent to surface of the cornea
